PDA Coupler Installation Guide

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Installation Guide

With optional Tape InsulationWith optional 25kV Mounting Brackets

PDA Coupler

EPOXY Mica Sensors

This document is a guideline only. It is not a machine-specific detailed instruction.

The installation of PDA couplers must be directed by an IRIS specialist or performed by a persontrained in the installation procedure to ensure that the integrity of the system is not impaired. Acompanion document, the Iris Verification Guide, provides guidance on how to validate theinstallation.

Iris Power LP cannot take responsibility for installations performed by others.

Iris Power LP


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The information contained in this document is the property of Iris Power LP, andis to be considered proprietary material. No part of this document may be

reproduced or transmitted in any form or by any means, electronic or mechanical,including photocopying and recording, for distribution to a Third Party without the

express written permission of Iris Power LP

PDA Coupler Installation Guide -Version 2.9

Feb 2009 Version 2.9 [Figure 1]Mar 2008 Version 2.8 [Figure 18]Mar 2008 Version 2.7 [Company Address]Mar 2006 Version 2.6 [Company Name]Nov 2005 Version 2.5

Apr 2001 Version 2.4May 2000 Version 2.3May 1999 Version 2.2May 1999 Version 2.1

! Iris Power LP, 2008. All rights reserved


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ATTENTIONRead Before Starting Installation

WARNING: Installations are often carried out in conjunction with rewinds orremedial work on a machine. It is possible to have an installation partiallycomplete but interrupted for AC Hi Pot testing. Refer to 0 for technical guidance.

NOTE: The Epoxy Mica Capacitor (EMC) should be kept clean during theinstallation. Painting or coating the EMC with foreign materials may degrade theelectrical tracking resistance of the couplers. The surface of the EMC may be

cleaned with cloth moistened with alcohol or approved solvents. If in doubt of thecompatibility of the solvent with the EMC, contact Iris Field Service TechnicalSupport [ref. Section 5.1].

The 6.9kV and 16kV EMCs may be mounted in any position, vertical, horizontalor suspended - where there is sufficient electrical clearance using the suppliedmetal clamps. When using the standard metal clamps, supplied with the couplerkit, the 25kV couplers can only be mounted in the vertical position. For horizontalor tilted mountings involving 25kV couplers, refer to 0 for technical guidance.

Special mounting plates for installing EMCs within the iso-phase bus duct oncurved surfaces are optional and can be supplied upon request.

When routing the coaxial cables from the EMCs to the Iris coupler terminationbox, the coaxial cables must be run along a grounded metallic surface. Insidethe generator, the coaxial cable can be routed and secured in place beside theRTD cables or circuit ring supports until they exist the generator housing into aconduit.


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Do’s and Don’ts

Do

" Pay attention to electrical clearances, both phase to phase and phase toground.

" Solidly ground the coupler termination box.

" Ground the conduit to the coupler termination box and ensure that this isthe only point of grounding.

" Follow IRIS installation procedures.

Don’t

" Don’t ever use adhesive backed cable tie anchors unless secured bymechanical means to secure the coaxial cables in place.

" Don’t run coaxial cables over top of the high voltage components wherethey could eventually fall onto those HV components.

" Don’t ever connect iso-phase bus duct sheaths together, or ground acrossinsulated supports, using solid runs of metal conduit. (Use non-conductingspacers, conduit, or insulators to maintain isolation between phases andground).

" Don’t bend HV cables to a radius less than 7 times the cable diameter.

" Don’t mount 25kV couplers in any orientation other then upright unlesscorrect mounting brackets are used.

" Don’t mount the EMC’s suspended by the centre post.


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1. Introduction

1.1 EMC Couplers

PDA couplers are high frequency sensorsused to detect partial discharges (PD)occurring within stator windings of motorsand generators. The sensors are oftenreferred to as Epoxy Mica Capacitors orEMCs [Figure 1]. Sensors can be used withthe portable instruments PDA-IV Lite™ andTGA-P™, or continuous monitoring systems

HydroTrac™ and HydroGuard™

1

, hereafterreferred to as the Iris instruments.

The couplers or sensors are permanentlyinstalled inside the generator with the highvoltage end connected directly to thegenerator winding.

Typically only two couplers per phase areinstalled on a winding regardless of thenumber of circuits per phase.

Figure 1. EMC Couplers

6.9kV, 16kV and 25kV

Note: For information about the instruments or systems, please refer tothe appropriate users manual.

For units with multiple circuits, depending on the size and importance attached toa unit, couplers may also be installed on some or all the circuits within a winding.See Section 2.2 for coupler locations. As the most common installation involvestwo couplers per phase, all references in the manual will refer to a two couplerper phase installation unless specifically stated.

During installation, the coaxial cable lengths connected to the couplers areadjusted such that a pulse originating from the system will travel through thecircuit rings to the connected EMC couplers, pass through the couplers andtravel down the coaxial cables to the termination box. Signals arriving at thecoupler termination box at identical times are classified as noise pulses. Pulsesthat originate at the C1 or C2 couplers will arrive at different times and beclassified as C1 or C2 PD pulses, respectively.

1 PDA-IV Lite, TGA-P Lite, HydroTrac and HydroGuard are products of Iris Power

PDA Coupler Installation Guide Introduction - 1


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It is this ability to separate the machine PD from system (or noise pulses) whichallows for accurate assessments of the PD data obtained during testing.

Note: For information about verification please refer to the IrisVerification Guide.

1.2 Description of EMC CouplersEpoxy-Mica Capacitor (EMC) couplers are made from track resistant high qualityelectrical grade epoxy, fully-rated for 25kV, 16kV or 6.9kV phase-to-phase classinstallations [Figure 1].

The epoxy encapsulates an internal epoxy-micacapacitor stack having a capacitance of 80-pF +/-4 pF for25kV couplers and 80-pF +/-3 pF for 16kV and 6.9kV

couplers [Figure 2]. The EMCs have a minimum partialdischarge extinction voltage of 25kV, 16kV and 6.9kVrms respectively, at 3pC sensitivity, tested according to

ASTM D1868 and IEC 60270.

Iris capacitor couplers are proof tested for 1-minute acvoltage as follows:

" 15kV for 6.9kV

" 33kV for 16kV

" 51kV for 25kV

The EMCs resemble post type insulators and, exceptfor the high voltage termination, require no further insulation to be applied in thefield.

Figure 2. EMC Coupler

Figure 1 shows the three EMC coupler sizes offered by Iris, they are:

Voltage ratings Height Diameter

6.9kV 95mm (3.75 in) 89 mm (3.5 in)

16kV 130mm (5.1 in) 89 mm (3.5 in)

25kV 205mm (8.1 in) 89 mm (3.5 in)

All three-voltage classes have imbedded brass terminals, top and bottom, to

which the electrical connections are made [Figure 2]. The low voltage terminal isrecessed into the bottom of the epoxy and contains a 3/8-in stainless steel plug,which is drilled and tapped to accept the small slotted screw to which the centreconductor of a 50-ohm coaxial cable is attached. The brass terminal on the highvoltage end (top) of the coupler is drilled and tapped to accept a 3/8-in brass bolt.The high voltage cable supplied comes with an “L” shaped ring lug crimped onone end, which is suitable for bolting to the top of the EMC.



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1.3 Installation Schedule A typical PDA coupler installation can take from 2 to 4 days for a six-couplerinstallation depending on the unit, mounting locations, amount of pre workperformed and the number of people assigned to the job. For a typical installation

supervised by an Iris specialist, the customer should provide 3 to 4 people,based on the complexity of the installation, to support the Iris specialist on-site.

The EMC coupler installation procedure is divided into several discretecomponents. However, some aspects of the various components areinterdependent and should be done in a logical order to avoid repeating work.The schedule below assumes that the unit is sufficiently dismantled, isolated andgrounded prior to the start of the installation.

With this in mind, a suggested order is as follows:

Day 1

" Safety Training and Site Orientation" Verify isolation and grounding points, pull (establish) required

permits/locks

" Open unit sufficiently to enable work to be performed

" Select the locations for mounting the EMC couplers and termination box.Select routing for any conduit.

" Review list of materials required (conduit lengths, mounting hardwaretooling required etc.).

" Start to layout, drill and tap the holes for the EMC mounting plates –

design and fabricate any mounting bracket supports required.

" Start removing insulation for the EMC HV connection from areas identifiedas the connection point.

Day 2

" Install the coupler termination box.

Note: The coaxial cable must run along a grounded metal

surface. Typically inside the generator, the coaxial cable can berouted and secured in place beside the RTD cables or circuitring supports.



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" Install metallic conduit (rigid or flexible) between the couplers andcoupler termination box where required. If the conduit spans isolatedcomponents or different ground planes, it is imperative that theconduits not bridge the gaps in order to avoid circulating currents (see0).

Conduit must be used once the coaxial cable exits the generatorframe to the Iris termination box. When routing the coaxialcable inside a protected enclosure, it may not be necessary torun in conduit.

" Calculate the required coaxial cable lengths

" Cut and prepare coaxial cable ends.

" Attach the HV cable to the coupler and install the insulating boot (or

insulate for the required voltage class if tapes are to be used).

" Connect the coaxial cables in the appropriate manner to the couplers.

Day 3/4

" Mount the couplers in the required locations and run the coaxial cablesto the coupler termination box.

" Connect the HV lead from the coupler to the copper bus

" Perform initial calibration and trim coaxial cables to their final lengths.

" Hard wire (solder) the coaxial cables in the coupler termination box.

" Perform final calibration/verification

" Insulate the HV/copper connection point of the EMC to the winding asrequired and secure the coaxial cables.

NOTE: The HV end of the coupler must be insulated, even ifinstalled in an area of all bare bus.



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2.2.1 Single Circuit – Directional PDA

With a single circuit machine, for each phase, one coupler (C1) is mounted asclose to the high voltage terminals as possible and measures the partialdischarge (PD) originating within the machine stator winding. The secondcoupler must be installed a minimum distance of 2m (6ft) from the “ C1” coupler

and is referred to as the “C2” coupler . This second coupler permits the Irisinstrument to recognize system noise and ensure that it is not counted as unitPD. System noise and PD are recognized and classified by the Iris instrumentbased on time of arrival.

Install the C1 coupler at the main leads (or as close as possible) formaximum sensitivity to machine PD.

On small single circuit machines the couplers are installed external to themachine, with the C1 coupler installed at the generator main lead/bus connectionpoint and the C2 coupler installed on the phase bus. This is referred to asDirectional PDA.

Single circuit with coup lers externalto machine

Single circuit machine with circu it rings allowing bothcouplers to be installed inside the generator

The “ C2” couplers are typically installed within the generator main bus duct or

iso-phase bus duct. In some cases the coupler may be installed in the voltagetransformer (VT) cubicle or in the circuit breaker cubicle. Please contact IrisField Service Technical Support if the either coupler is to be placed on a tap offof the main bus (Section 5.1). If there is no VT cubicle, then the system endcouplers can be fitted into the circuit breaker cubicle, provided the verification forinstallations involving taps has been satisfied [See the Iris Verification Guide].

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It is desirable that there be no feeders, splits, CTs, VTs, etc. located between thecoupler pairs on a given phase. The presence of such between the couplers canlead to signal distortion, and imperfect noise reduction. If necessary, it is betterto install the pair of EMCs on either side of the CTs rather than to have the CTs

between the stator winding and the “C1” coupler.

In some cases surge capacitors are present near the machine terminals. In thissituation, it may be necessary to install either the C1 or C2 coupler on the busnear the surge capacitors. Do not connect the EMC to the top of the surgecapacitor or after the cable connecting the surge capacitor to the bus, connectthe EMCs directly to the bus.

2.2.2 Two Circuit Connections

The circuit ring design may incorporate any one of the following configurations.

" Split ring - One ring per each circuit

" One common circuit ring with both circuits connected to it

2.2.2.1 Split ring

In most two-circuit designs, thereis sufficient distance betweencircuits that both the C1 and C2couplers are installed as close tothe line coil as possible. There aresome machines where there is

insufficient circuit ring length (lessthan 1m (3ft)) to install one or bothof the couplers, in which case itmay be necessary to install thecouplers in a directional PDAconfiguration [see Section 2.2.6].



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2.2.2.2 One common ring

For two circuits on a common ring, ifthe unit is small to medium in size, thena two coupler per phase “directional”installation would be the probablechoice [see Section 2.2.1]. If the unit islarge, or the customer insists on fullcoverage, then it is possible to install 3couplers per phase as shown. The C1(C3) coupler would be the commoncoupler paired with C2 (C1) and C3(C2). An alternative name schema isalso shown in parentheses.

If both circuits on a phase are within2m (6ft) there is no advantage to

installing a coupler on each circuit.

(Coupler C3)

(Coupler C2)

(Coupler C1)

2.2.3 Three-Circuit Connections

Regardless of the circuit ring design, there will be a single circuit on one side ofthe mains and two circuits on the other. The circuit ring with the single circuit willalways be the C1 coupler circuit. The typical configurations will be:

" Two couplers per phase

" Three couplers per phase

2.2.3.1 Two couplers per phase

When installing two couplers on athree-circuit machine: the C1coupler will be installed on thecircuit ring (or side) with the singlecircuit. The C2 coupler will beinstalled on the circuit farthest awayfrom the main leads.

Remember that each circuit ringmust be longer than 1m (3ft). If not,refer to Section 2.2.6.



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2.2.3.2 Three couplers per phase

The C1 coupler will be installed onthe side containing the single circuit.

The C2 coupler will be the circuitfarthest away from the main lead andthe C3 coupler will be the circuitbetween the C1 and C2 circuits(closest to the main leads on the twocircuit side). The circuit ring buslength to the C3 coupler must be >1m(3ft) in length, in order for the C3 toproperly function.

C1 will be the common coupler,paired with both the C2 and C3

sensors. Note: verify C1 and C2 firstand then match C3 to the C1 circuit.

2.2.4 Four Circuit Connections

It is common to install only one coupler pair (two couplers) per phase on a multi-circuit machine. However, in order to have the ability to further identify on whichpath the partial discharges are occurring, a customer may choose to installmultiple pairs, usually two, per phase.

Installing couplers on a four-circuit machine is identical toinstalling two – two circuitinstallations (Section 2.2.2).Typically, the last two circuitson each ring (farthest fromthe main leads) will be pairedtogether and be labelled theC1 and C2 couplers. Thetwo circuits closest to themain leads will be labelledC3 and C4. This will be the

same, regardless of thenumber of circuit rings.

All the circuit rings on whichan EMC coupler is to beinstalled must be must be>1m in length.



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2.2.5 Other Circui t Ring Configurations

Any time there are an unequal number of circuits, the common coupler will be onthe side of the main leads containing the fewest number of circuits. Pair up thecouplers as per a normal installation, for the odd number circuit pick acorresponding circuit to act as the common circuit.

To avoid long lengths of coaxial cable, the common circuit selected should be inthe same relative position on the winding. Never pair two circuits that are on thesame side of the main leads.

Note: it is very rare to install more than 4 couplers per phase and allthe circuit rings on which an EMC coupler is to be installed must be>1m in length.

Some windings (wave wound) will have all the circuit rings for a given phaserunning in the same direction. If the unit is a small diameter, the couplers should

be installed external of the machine in a directional PDA configuration [seeSection 2.2.1].

2.2.6 Insufficient Circuit Ring

When there is insufficient circuit ring, that is less than 1m (3ft) for a directionalPDA install, there are two typical configurations to consider:

" Directional PDA

" Couplers on the bottom of the winding

2.2.6.1 Directional PDA

Often the circuit rings will be


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system will not be detected by the couplers. Note: When calibrating, do notconfuse the ringing pulse as the calibrating pulse.

For bars, the couplers can be installed on the series clip connecting the line barto the second bar in from the line end. There are two possible configurations,using the original series clip and an extended series clip.

Original Series Clip

Figure 4. Stud Brazed to Bottom

Stud brazed to the bottom of aseries clip and the series capmodified to allow the connectionof the EMC HV cable. Thedifficulty with this configuration isto adequately insulate over topof the stud and HV cable.



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Extended Series Clip

Figure 5. Extended Series Clip

2.3 High Voltage Connection

The high voltage (HV) side of the EMC coupler is connected to the generatorcircuit ring/terminals/bus using the supplied HV cable. For optimal noise

separation, the HV connection should be made within 1m (3ft) of the connectionbetween the high voltage coil/bar and the circuit ring.

The HV cable is fully insulated for 15kV or 25kV classes of operation (accordingto machine voltage rating) and is unshielded; therefore, no stress relief isrequired. The cable should be kept as short as possible and should be routed soas to maintain adequate electrical clearances to ground or other phases for thevoltage class of the machine (see Section 2.4).

Remember, the 6.9 kV and 16kV couplers may be mounted in any orientation;however, the 25 kV style couplers should only be mounted upright unlessoptional mounting clamps are used [see 0]. Refer to Section 2.4 for Coupler

Mounting considerations.

In order to determine where the high voltage connections can be made, theremust be some understanding of the unit construction, type of insulation usedalong with coil and circuit ring design. The most common windings encounteredare the roebel bar and multi-turn coil with an internal transposition, but there areother coil designs that may be encountered. Depending on the design, certain



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installation methods can be successfully performed on one machine and lead toa potential failure on another machine.

2.3.1 Coil Jumper

In order to ensure the integrity of thetransposition for multi-turn coils, Irisrecommends that the high voltageconnection to the couplers be madeat either the jumper between the 1st coil and the circuit ring, or directly tothe circuit ring. If consideringanother placement, please contactthe winding manufacturer or IrisTechnical Support (Section 5.1) forassistance.

Figure 6. HV on Jumper

2.3.2 Circuit Ring

Depending on the type of circuit rings, the connection point can be via a drilledand tapped hole, through-drilled (not as good as a tapped hole), brazed on tab orfabricated clip.

2.3.2.1 Rectangular Copper Bus

Where the circuit rings are made of flat,rectangular copper, and of sufficient crosssectional area, a hole can be drilled andtapped through the copper and the highvoltage cable connected directly to the bus.

Figure 7. Tap into Circuit Ring



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Figure 8. Tab on Circuit Ring

Figure 9. L-shaped Bracket on Circuit Ring

If the rings are of insufficient cross-section, it may be necessary to braze orfabricate a clip using the supplied copper strap. Where the circuit rings are madeof large diameter copper tubing, it is possible to drill and tap directly into thetubing. When using this method, a flat spot should be filed in the ring to

accommodate the ring lug to ensure a solid electrical connection.

2.3.2.2 Stranded Circuit Rings

Where the circuit rings are made ofstranded copper, (typically found onolder coil windings), it is best to look fora bulge in the insulation where thecircuit ring tap is connected to the coillead. This is usually a brazed(slugged) connection at which point a

small copper tap can be brazed, or acopper clip fabricated that encircles thecircuit ring when tightened with a bolt.

Figure 10. Brazed Connection

Caution: If the strands are individually brazed and insulated from each other, itis probable that the winding has an external transposition and the EMC’s willhave to be mounted external to the machines in a directional PDA configuration.This type of winding is now quite rare, normally found in older European

designed generators, but can also be found in North American designs as well.For this style of winding, the couplers must be installed external to the winding ina directional PDA configuration. [Section 2.2.1]



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Figure 11. Two piece fabricated clip for a rectangular, stranded circuit ring

NOTE: the supplied copper strap is hard, un-annealed copper. To soften(anneal) the copper, heat with a torch until the copper is a dull red colour,allow it to cool slowly. Quenching or over-working will case harden copper.

Steps for preparing the HV cable:

Determine how the high voltage cable will connect to thegenerator winding, the installation kit provides theappropriate brass hardware in both imperial (3/8”-16NC) and

metric (10mm). Two copper straps are also provided tofabricate tabs or clips on site.

" Whether the high voltage cable will connect to the circuit ring or the jumper between the 1st coil and the circuit ring

" Whether using a brazed or fabricated copper strap

" When connecting the insulated high voltage cable directly to the circuitring/circuit ring tap, drilling and tapping is the preferred method,although drilling a through hole and using a bolt and nut are alsoacceptable.

Temporarily attach a high voltage cable to the EMC and selectthe most suitable mounting location. See Section 2.4 forCoupler Mounting Considerations, specifically couplerorientation and electrical clearance requirements.



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" Ensure bend radius of cable is not less than 7 times cable diameter. It ispreferable that the HV cable be oriented to curve back across the top of theEMC once installed.

" Ensure main clearances phase-to-phase and phase-to-ground are notcomprised. [Section 2.4]

" Where possible do not “reach” over top of an adjacent phase. If this isnecessary, use an insulated spacer block (Dacron felt and glass block)saturated with epoxy and secure in position. This will ensure that thehigh voltage lead does not come in contact with another phase.NEVER simply arch it over a live point. It may sag over time.

If the installation is being performed on a unit that has been inservice, in all probability, insulation will have to be removedfrom the EMC high voltage connection area.

Figure 12. Scarf Joint

Prior to cutting into the insulation, verifythe location of the coupler to insure thatthe coupler can be installed in that area.Only qualified personnel should removeand reapply insulation. If unsure of thesite, before removing insulation, use siteverification couplers (SVCs) to measurethe response to a coupled signal. (Seethe Iris Verification Guide).

A taper (scarf) must be cut in theinsulation to facilitate the re-insulation ofthe joint. A 13.8kv machine should haveminimum of a 1-inch scarf joint.

A standard two-piece metal mounting bracket is used to securethe EMC coupler in position. The mounting bracket slidesinto a machined groove at the base of the EMC and it hasfour slotted holes to accommodate 6mm (¼ in) bolts forsecuring the brackets in place. Using the template in 0,layout and drill the holes for the EMC mounting brackets. Holes can be through drilled using a 7mm (5/16-in) drill bit,

or if the hole is to be tapped, a 5mm (13/64-in) drill bit isrequired.

Assuming the insulated HV lead (supplied) is to be connected tothe EMC, determine the length of cable required to connectthe top terminal of the coupler to the selected spot on thebus or connector. Allow sufficient length so the cable will notbe under tension. Remember to make some allowance for



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thermal movement of circuit rings. Trim the HV cable to suitand crimp on the straight ring lug supplied, or one suitablefor the installation.

Note: Where there is minimum separation, $2m (6ft), between the

C1 and C2 couplers, the high voltage connection leads must be cutto identical lengths for each coupler pair.

If the supplied HV cable is not used then a cable of equivalentrating (unshielded)—must be used and kept to a minimumlength. IRIS recommends a maximum of 60cm (2 ft).

If a copper strap is used, a 10mm (3/8-in) hole should be drilledin one end of the copper strap to accommodate the couplertermination lugs (supplied) and the brass bolts (supplied).The other end can be drilled to accommodate the bolt sizeassociated with the circuit ring and/or terminal connectors, orbrazed as a tab if desired. This copper strap will requireinsulation on site as required.

NOTE: The EMC should be kept clean during the installation.Painting or coating the EMC with foreign materials may degrade theelectrical tracking resistance of the couplers and must be avoided.The surface of the EMC may be cleaned with a cloth moistenedwith alcohol or approved solvents. If in doubt of the compatibility ofthe solvent with the EMC, contact Iris Field Service Technical

Support (Section 5.1).

For re-insulating the connection area, a “Y” connected joint[Figure 13] is much easier to tape than a “T” connection[Figure 14] as shown below. When re-insulating using micatape, the tape width should be no less than 2cm (¾in) andno wider than 2.5cm (1in).



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Figure 13. Y-joint Figure 14. T-joint

For class F windings, an epoxy or polyester resin must be used as a binderand applied between every layer of insulation. If the winding is a class Binsulation, an air-dry varnish can be used. All taped joints will require at least

one layer of glass or Dacron tape be applied as a protective layer for the micatape.

Caution: Follow all standard safety procedures for winding repairs whenworking within a winding. This includes cleanliness and proper insulation.

2.4 Coupler Mounting ConsiderationsWhen selecting the location for mounting the couplers, ensure there is sufficientspace to install the couplers without compromising the high voltage integrity ofthe winding or output bus. There must be adequate voltage clearance betweenthe low voltage portion of the EMC coupler and coax cable to any high voltagecomponent. Similarly the high voltage portion of the EMC coupler and thecoupler HV leads must be a safe distance from any grounded structures andother phases.

The recommended and absolute minimum distances in air between insulatedhigh voltage and low voltage components are:

Rated voltage Recommended Minimum

6.9kV 25 mm (1 in) 6mm (0.25 in)

16kV 50 mm (2 in) 20mm (0.75 in)

25kV 150mm (6 in) 63mm (2.5 in)

Each EMC is clamped into place on a suitably flat surface using a 2 piecemounting clamp, fabricated for this purpose and supplied as part of theinstallation kit. The 2-piece mounting clamp should fit snugly and securely in themachined groove at the base of the EMC. If this is not the case, please contactIris Field Service Technical Support. The 6.9kV and 16kV coupler may bemounted in any position, vertical, horizontal or suspended - where there issufficient electrical clearance, using the supplied metal clamps. The 25kV



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couplers can only be mounted in the upright position with the conventionalbracket.

For installations requiring mounting the 25kV EMC in the horizontal or suspendedposition, Iris Power can, as an option, supply special support blocksmanufactured for that purpose. Where necessary, Iris can supply, as an option,

mounting support brackets fabricated to “tilt” the EMC at no greater than a 45# angle to accommodate an installation. See 0 for further information, or contactyour Iris Sales Representative.

Iris also supplies special steel mounting plates forinstalling EMCs within the iso-phase bus duct orother curved surfaces as shown in Figure 15. Please contact your Iris Sales Representative forfurther information.

The plate is used to give the EMC a flat mounting

surface inside the iso-phase bus. The length wiseorientation of the plate and mounting bracketsalong the duct allows for the maximum clearanceand stability to reduce mechanical stress on theEMC. Figure 15. “ Curved” mounting

arrangement

Figure 16. Fabricated mounting plate

In some situations, a plate to which thecouplers will be secured may need to befabricated and installed on-site. Anexample is shown in Figure 16.

If necessary, drilling new holes throughthe supplied support clamps is allowableonly when the EMC is sitting on a flatsmooth surface. The clamp should notbe modified if the EMC is to be mountedin the horizontal position or mountedupside down.



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When installing in the horizontal position,the EMC brackets should be alignedvertically (12 and 6 o’clock positions) formaximum support of the EMC as shown inFigure 17.

Figure 17. Horizontal mounting

2.5 Insulating the EMCIt is recommended that the HV connection at the top of the EMC be insulatedregardless of the location selected for the installation. The only exception iswhere the EMC is installed inside an Iso-Phase bus and there is insufficient roomfor the insulation.

Iris provides a pre-formed silicone rubber mould, orBoot, which seals tightly over the high voltage cable andthe first shed of the coupler. For customers who prefertape insulation, please refer to 0.

The Boot and these tapes are designed for normal

operating temperatures,


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trim off the smaller diameter “neck”. Care must be taken when cutting off the16kV “neck” to ensure that the remaining part of the boot is not damaged.Use a sharp knife or razor knife for trimming the boot.

Take the boot in hand and collapse the boot like anaccordion. The boot will be installed over top of the“L” ring lug. If desired, to assist installation, take theHV cable and smear a light coat of Siliconeapproximately 7cm (2in) up the HV cable from thering lug. The Silicone will act as a lubricant. Therecommended silicone is Clear Guide, a wire pullinglubricant or SU5005RTV silicone adhesive, which isboth a lubricant and a sealant.

Carefully insert the ring lugthrough the neck of the boot.

Push the boot high enough thatthere is sufficient clearance toinstall and tighten the boltthrough the ring lug to the EMC.

5. Bolt the HV cable to the top of the EMC;check the orientation of the cable beforetightening to ensure that the cable will arcover top of the EMC. Place a small dab ofloc-tite on the brass bolt and tighten in place,

but do not over tighten to the point where thelock washer starts to spread.



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Start the lip of the boot over the firstshed of the EMC, place hands oneach side and gently stretch and rollthe boot to the front of the EMC usinga slightly downward pressure. Thiswill force the boot over the shed andsnap into place. Unfold the boot andsnap into place over ONLY the firstshed of the EMC. No lubrication orsealing is required on the EMC.

7. Once the boot is positioned over the EMC,straighten the HV cable and position the neckof the boot so that it is in a relaxed position asshown.

8. Wipe off any excess silicone.

If RTV silicone adhesive is being used; allow itto set for ½ hour, then the EMC will be readyfor installation.

9. To remove the boot from the EMC - withboth hands hold the rim of the boot andgently pull it away from the EMC and atthe same time peal it back towards theHV cable.

Caution: Do not paint the siliconeboot or EMC.



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NOTE: In the unlikely event the boot is aloose fit over the 16kV cables, it isrecommended that two half-lap layers of

Silicon Guideline tape (provided by customer)be wrapped around the top of the boot/cable.This will seal the top of the boot to the cablepreventing the ingress of moisture andcontaminants. Recommended are a full layer(i.e. the width of the tape) of SiliconeGuideline tape on the boot and a full layer onthe HV cable as shown.



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3. Termination Box Installation

3.1 Overview

Figure 18. Termination Box

The coupler termination box contains theBNC jacks/terminal board to which thecoaxial cables from the EMC sensors areterminated. The BNC connections areused for all Iris portable instruments andcontinuous monitoring systems usingcapacitive type sensors.

RG 58 (50 ohm) coaxial cables are usedto connect the couplers to the terminationbox. The termination box contains a1500 ohm resistor and 75 V surgearrestor on each connector termination.The arrangement ensures that the normal60 Hz (or 50 Hz) voltage from the 25 kVEMC couplers will be less than 600 mVand less for lower voltage couplers andlimits voltage rise under abnormalconditions.

The continuous monitoring systems, or

Tracs, use a junction box rather than atermination box. Please refer to theappropriate Trac installation guide fordirections regarding the installation of the

junction box.

3.2 InstallationThe coaxial cables on a given phase are usually different lengths; but often

selecting a central location between the coupler pairs to mount the terminationbox will minimize the total length of coaxial cable required and the amount of

excess cable that will have to be stored. This is usually directly opposite (180#)from the incoming phase leads into the generator. If it is not possible to centrallylocate the termination box, approximately 11m (36 feet) total of excess cable canbe stored in an open loop inside the termination box. A second box may berequired to store longer lengths of coaxial cable if required. The termination boxis mounted with the door hinge at the bottom and the locking clips at the top.

PDA Coupler Installation Guide Termination Box Installation - 24


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The standard coupler termination box is a NEMA 4X corrosion resistantfibreglass box with no knockout provision for coaxial cable access (Iris has anoptional stainless steel box for special applications and when placed in highlycorrosive environments, but this would have to be specified at the time of order).The coaxial cable access location (top, bottom, sides or back) and hole size is

determined at the time of installation and punched or drilled before mounting.The termination box can be mounted on any vertical surface, such as a wall, theside of a cubicle, structural I beam or generator terminal box. It should beinstalled at approximately eye level and have reasonable access to a 110/220 Vpower outlet. The termination box itself does not require power; power is onlyrequired when performing online testing with the Iris portable instruments.However, the Iris continuous monitoring systems do require permanent power.

Steps for Installing the Termination Box:

1. Determine a suitable location for the Termination Box.

2. Remove the internal circuit board from the box, and set aside forsafekeeping.

3. Drill out the appropriate size hole for the coaxial cable conduit at thedesired location in the Termination Box and install a suitable adapter. Usean appropriate drill bit, hole saw or hole punch. [See Section 4.2 forinformation about conduit sizes]

4. Using the template in 0, mark the holes for attaching the box.

5. Mount the Termination Box by drilling and tapping, or using bolts asnecessary.

6. Run the #4 copper wire (supplied, green jacket) from the ground bolt onthe right side of the termination box to a permanent station groundlocation. This bolt is used to ground the components inside the terminationbox and also the metallic conduit. This should be the only point where theconduit is grounded to minimize risk of circulating currents due to differingground potentials.

PDA Coupler Installation Guide Termination Box Installation - 25


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4. Installing Coaxial Cable

4.1 OverviewThe coaxial cable connects the low voltage terminal of the EMC coupler to thetermination board inside the coupler termination box. The coaxial cables from acoupler pair in a phase will usually be different lengths and must be routed alonga grounded metal surface from the EMC to the termination box.

4.2 InstallationTypically, inside the generator, the coaxial cable can be routed and secured inplace beside the RTD cables or circuit ring supports until they exit the generatorhousing into a conduit. Whenever the coaxial cables exit a metal enclosure,such as the generator frame, the coaxial cables must run in grounded rigid orflexible metallic conduit, preferably away from and not on open cable trays alongside power cables. Some customers may insist on using conduit inside thegenerator. If so flex conduit is preferred over rigid conduit. To minimize conduitruns, where possible, multiple coaxial cables can be run through a commonconduit.

The conduit must provide a continuous ground plane and should only begrounded at one end. Iris recommends grounding the conduit only once atthe coupler termination box. Multiple ground points along a condui t may

result in high circulating currents, which may cause the conduit tooverheat and melt the coaxial cable insulation. This is especially true inisolated phase bus arrangements.

Important: When installing conduit between various Isolated Phase Bus(IPB) components, be very careful not to inadvertently short circuit or

jumper some IPB sheath insulated gaps. An insulated nylon bushing or ashort section ~ 5-10cm (2-4 in) of PVC conduit installed at the EMCcoaxial cable exit point will be sufficient to insulate the conduit from thebus. It may also be necessary to insulate the conduit from the conduitclamps and hangers to avoid ground loops. [0].

In order to minimize installation damage, all conduit sizes should comply withlocal electrical safety codes. In absence of local codes, the minimum conduitsizes in Table 4-1 are recommended.

PDA Coupler Installation Guide Installing Coaxial Cable - 26


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Coaxial cables Condui t TradeSize

3 to 6 Coaxial Cables 2cm (¾in)

9 Coaxial Cables 2.5cm (1in)

12 Coaxial Cables 3cm (1 ¼in)18 Coaxial Cables 4cm (1 ½in)

24 Coaxial Cables 5cm (2 in)

Note: Thesemeasurements arefor rigid conduit onlyand should beincreased 1 size forthe 3 to 12 coaxial

cable installations if aflexible conduit isused.

Table 4-1

Meets or exceeds Canadian Electrical Safety Code, Part 1, Rule 12-1014

Steps for Installing the Coaxial Cable:

1. Determine the route for conduit runs from each set of couplers to the locationof the coupler termination box. Conduit is not required within the generatorand enclosures where the coaxial cable can be securely fastened

continuously against a grounded metal surface.

2. Rigid conduit is preferred and should be used when spanning between thegenerator frame and the generator pit wall.

3. Install the required metallic conduit between the coupler locations and thecoupler termination box. Since the conduit is only grounded once at thetermination box, install conduit insulators as required.

4. For each coupler, determine the path the cable. When cutting the coaxialcable, add 3 m (10’) extra to the calculated length for an adjustment

allowance. The complete path will include both that taken inside cubicles andthat running through the conduit installed in step 3 above.

5. Below is a suggestion for labelling the coaxial cables for easy identification.

Phase C1 Coupler C2 Coupler

A A-1 A-2

B B-1 B-2

C C-1 C-2



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4.3 Preparing Coaxial Cable at EMC End

Figure 19. Trimming of coaxial cable

1. Cut the outer jacket backapproximately 2.5cm (1in).

2. Carefully trim off the exposedshield flush with the jacket.

3. Trim back the centre conductorinsulation approximately9.5mm (3/8in).

Crimp on the ring lugsupplied in the kit.

Position the black

heat shrink tube,centred over thetrim area of the

jacket and centreconductor.

Using a heat gunshrink the tubinginto position toensure the coaxialshield will be

isolated fromground.

Figure 20. EMC coaxial cable connection

Caution: Overheating during the shrink process may damage thecentre conductor insulation, resulting in the centre conductorgrounding to the outer shield.



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Figure 21. Bottom of EMC

Prior to installing thecoaxial cable,check that thestainless steel plugis tight in the

bottom of theEMC.

Dab a small quantity of loc-tite on thesmall coaxterminal screw,and then wipe offany excess.

Position the ring lug atabout the 9 o’clockposition from themachined grooveand tighten thescrew. Do not exitdirectly through thegroove or try to

press the shrink-covered portioninto the groove. Ifthe EMC is to beinstalled in acausticenvironment suchas petrol-chemicalplants or subject tosevere vibration, acovering of RTV

(silicone rubber)can be appliedover the exposedbrass insert, ringlug and coaxialcable.

Figure 22. Coaxial cable connected to EMC



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NOTE: When trimming the coaxial cable ensure that the exactsame amount of coaxial cable is trimmed off each pair of cables.

Approximately 11m (36ft) of excess coaxial cable can be stored

in open loops inside the termination box. If there is anexcessive length of coaxial cable to be stored, it may benecessary to install a second box, or the coaxial cable canbe pulled back into the machine or generator terminal boxand secured in open loops there.

The excess cable should be formed into an open loop not a coil,as a coil can increase the inductance of the cable and maydistort the partial discharge pulses. If the coaxial cable ispulled back into the machine, or terminal box, ensure thatthe coaxial cable is securely fastened by mechanical

means away from the electrical components.

4.4 Coaxial Cables at Termination Board

Figure 23. Termination Board coaxial cableconnection

4. Trim the outer shield of the coaxialcable about 9mm (5/8in).

5. Carefully unbraid the shield anddivide into two equal parts and thentwist the strands together toconsolidate the loose strands.

Strip the centre conductor insulation to approximately 6mm (¼in) from thetwisted shield.



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Figure 24. Coaxial cable connected to termination board

Insert the exposed conductors into the fork terminals with the centreconductor in the middle fork and each of the shield conductors on the twoside forks.

Secure all the coaxial cables in place with the cable ties. At this point, useonly the cable tie nearest the connection to be soldered.

Note: Care must be taken during soldering to avoid overheatingthe shield conductors and melting the insulation between the shieldand the centre conductor. Do not try to solder all 3 points on a

given cable in quick succession.

Solder the connections.Soldering the same terminal oneach of the coaxial cables insequence will allow sufficient timefor the insulation to cool beforesoldering the next terminal.

Trim the excess strands flush withthe solder terminal.

Figure 25. Trimmed and solderedconnection



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Figure 26. Securing coaxial cable with cableties

Inspect the soldered joints toensure proper soldering and nomissed or cold (dry) soldered

joints.

Check that no stray strands areshorting out the terminals.

Position the coaxial cables anduse the last remaining cable tieson the board to secure the threecables in a bundle.

Secure the excess coaxialcable neatly inside thetermination box.

For most installations, theexcess coaxial cable can bestored in an open loop inside thefibreglass termination box.

By using “sticky backs” andnylon cable ties, approximately atotal of 11m (36ft) of coaxialcable can be stored inside thetermination box. Secure theexcess cable as described inSection 4.3 steps 15 and 16.

Finish the coaxial cableinstallation with a final TDR,verification and resistance checkas described in the IrisVerification Guide. Figure 27. Securing excess coaxial cable

in termination box



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5. Customer Support Services

5.1 Technical SupportIf you require additional technical support, please contact Iris’s Field ServiceTechnical Support at e-mail [email protected] or fax 1-416-620-1995or telephone 1-416-620-5600 from 9:00 a.m. to 3:00 p.m. Eastern StandardTime.

5.2 SalesIf you would like to obtain additional installation materials, please contact Iris’sSales Department at 1-416-620-5600, 9:00 a.m. to 3:00 PM Eastern StandardTime.

Please check our website http://www.irispower.com/ for the latest productinformation, available services and software updates.

5.3 Product Updates, New ProductsFor firmware upgrades, software upgrades, product updates and new products,visit our website, www. irispower.com regularly. Contact our Sales Departmentat 1-416-620-5600, 9:00 a.m. to 3:00 p.m. Eastern Standard Time for moreinformation.

PDA Coupler Installation Guide Customer Support Services - 35

mailto:[email protected]://www.irispower.com/http://www.irispower.com/http://www.irispower.com/http://www.irispower.com/mailto:[email protected]


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PDA Coupler Installation Guide Customer Support Services - 36


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Template Guides

Coupler Mounting Bracket

Mounting clamps arrangement & dimensions.

PDA Coupler Installation Guide Appendix A – Template Guides - 37


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Termination Box Mounting

E n

d V i e w

B o

t t o m

V i e w

S i d e

V i e w

0 . 1

2 "

( 3 m m )

8 . 5

" ( 2 1 6 m m )

0 . 4

1 "

1 0 m m

6 . 0

"

( 1 5 2 m m )

6 . 0

"

( 1 5 2 m m )

# 1 0 - 3 2

P a n H e a d

0

. 3 1 "

0 . 5

0 "

8

m m

1 3 m m

x

S l o t

1 . 3

1 " ( 3 3 m m )

1 0 . 9

4 " ( 2 7 8 m m )

1 0 . 5

" ( 2 6 7 m m )

9 . 1

2 " ( 2 3 2 m m )

4 . 9

4 "

( 1 2 5 m m )

1 0 . 5

" ( 2 6 7 m m )

Q u i c k - R e l e a s e C o v e r E n c l o s u r e

N o

t e s :

1 ) M o u n

t i n g

f e e

t a r e

0 . 1

6 " ( 4 m m

) t h i c k

.

2 ) Q u

i c k

r e l e a s e c

l a m p s n o

t s

h o w n

i n " E n

d V i e w

" .

3 ) T h e g

r o u n

d i n g s

t u d M U S T b e c o n n e c

t e d t o s

t a t i o n g r o u n

d .

D r a w n B y : D a v e P r o s s e r

D a t e D r a w n : J u

l y 9 ,

1 9 9 9

A p p r o v e d B y :

D a t e A p p r o v e d

:

c t b - d i m s . c d r

D r a w i n g # : I S O

- 0 3 9

R e v i s i o n # : 0 0

I R I S

P O

W

E

R

E

N

G

I N

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E

R

I N

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I r i s P o w e r E n g i n

e e r i n g

1 W e s t s i d e D r . , U n i t 2

E t o b i c o k e , O n t a r i o ,

C a n a d a M 9 C 1 B 2

t e l ( 4 1 6 ) 6 2 0 - 5 6 0 0 ,

f a x ( 4 1 6 ) 6 2 0 - 1 9 9 5

C o u p l e r

T e r m i n a t i o n B o x M o u n t i n g D

i m e n s i o n s

3 / 8 “ N C

G r o u n d i n g S t u d

Coupler termination box dimensions.

PDA Coupler Installation Guide Appendix A – Template Guides - 38


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lnstallation Materials

The following list (next page) is typical of the materials supplied by Iris to install aset of PDA couplers. PDA coupler sets may be composed of 6 EMC couplers, ora higher multiple of 3. The table shown provides information on quantities for afull 6-coupler installation kit. Any variations of these installation types wouldinclude only the appropriate components of these lists. Other materials may besubstituted provided that the materials used are intended for electrical use andare compatible with the electrical installation.

Note: Additional items, NOT SUPPLIED by Iris but which may berequired to provide a complete installation, are shown on the nextpage of this Appendix.

Six EMC Coupler set - supplied

Item Quantity Product Description

Epoxy - Mica Capacitor 6Epoxy type coupling Capacitors, fitted with coaxial cablecrimp ring lug and screw at base

High Voltage Cable 6 pieces16kV or 25kV jumper cable 60 cm (24 in) with L- shapedcoupler end ring lug installed

Ring Lug 6 pieces Burndy #2 AWG - 1/2 in. for jumper cable, straight

Copper Strap 2 piecesStrips 60 cm (24 in) x 2.5 cm (1 in) x 0.32 cm (1/8 in) - toprovide termination points for coupler cable lugs to bus.

Bolts/washers/lockwashers

12 sets

For connecting Epoxy - Mica Capacitor cable ring lugsto high voltage connection point6 sets - 3/8in x 1in imperial thread6 sets – 10 mm

Insulated Boot 6Preformed high voltage insulating boot for coupler HVconnection

Clamps 6 sets Hold-down clamps for Epoxy - Mica Capacitors

Coaxial Cable 150 m (500 ft) RG58 C/U 50 ohm coax cable

Polyolefin Shrink Tube 6 pieces2.5 cm (1 in) to insulate coaxial cable, coupler endshield braid

Termination Box 1 Termination of coupler output coaxial cables

Insulated Wire - #4 3 m (10 ft)600 V insulated wire for grounding coupler terminationbox. (Green)

PDA Coupler Installation Guide Appendix B – Installation Materials - 39


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Optional Materials and Hardware


25kV EMC HorizontalMounting Kit

2 pc block designed for mounting the 25 kV couplers inthe horizontal or suspended positions

Angled Support Bracket Designed for tilting the 25 kV couplers at a 45# angle toaccommodate an installation

Iso-Phase Bus MountingBrackets

For mounting the EMC couplers on a curved surface

SAP Tape - 5 cm (2 in)wide++

2 rolls** Self-Amalgamating Polymeric Tape. Black in colour,used to insulate. ROTUNDA 2501

Silicone Rubber Tape - 2.5cm ++ (1 in wide)

2 rolls** Self Fusing - Orange in colour ROTUNDA Protectivecover over SAP tape

Electrical Putty - 5 cm (2 in)wide++

8 strips Electrical Putty to mould around connections to be taped.Supplied in strips 33 cm (13 in) long

**Note: Insulating materials supplied are sufficient for insulatingthe EMC; additional quantities of tape may be required.

++Note: Only required if boot is NOT used.

Additional MaterialsFor a complete coupler installation, depending on bus coupler installation

configuration and layout, additional materials may be required.

Note: These additional materials are supplied by the customer anddo not form part of the Installation Kit supplied by Iris.

These additional materials may include some or all of the following:

Materials Required - Condui t

Metallic Conduit Rigid or flexible may be usedConduit should have continuity over the length and may requiresimple point grounding to avoid ground current circulation.

Ground at the termination boxRecommended conduit sizes for:6 coaxial cables – 2.5cm (1in)12 coaxial cables – 3cm 1¼in)

Miscellaneous Conduit Fittings To run conduit from the EMC to the termination boxNote pull boxes are recommended ~ every 15 feet

Conduit Mounting Brackets Insulated clamps/brackets may be required to avoid circulatingcurrents in the conduit.



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Materials Required – Typical Hardware

Nuts, bolts, lock & platewashers ¼-20 x 1in

Termination Box – Qty 4EMC Mounting Brackets

3 couplers Qty 126 couplers Qty 24

Miscellaneous Hardware Depending on installation, additional hardware and materials forfabricating mounting brackets may be required

Cable ties and clamps Required to fasten the coaxial cables into place.No adhesive backed fasteners can be used, unless alsosecured mechanically.

Materials Required – Miscellaneous

Miscellaneous hand tools

Electric drill, drill bits, and taps

Vacuum

Crimping tool for Burndy #2 AWG – ½ in ring lug

Razor Knives, wood chisels, files

Loc-tite, RTV, epoxy



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Segregated IPB Systems

Important: When installing conduit between various Isolated Phase Bus (IPB)components, be very careful not to inadvertently short circuit or jumper some IPB

sheath insulated gaps. An insulated nylon bushing or a short section ~ 5-10cm(2-4 in) of PVC conduit installed at the EMC coaxial cable exit point is sufficientto insulate the conduit from the bus. It may also be necessary to insulate theconduit from the conduit clamps and hangers to avoid ground loops.

IPB Configurations

Figure 28

Figure 29, and Figure 30 illustrate three (simplified) typical ISO phase Busconfigurations, showing insulated bus support mounts and insulated bellows withsegregation at the Generator (Figure 28) or Generator Transformer (Figure29Figure 28and Figure 29 show systems where each phase is insulated

separately and Figure 30 where they are common.

The KEY factor is that the phase buses are grounded at ONE point only toensure that circulating currents within the system are prevented.

Generator

InsulationInsulated Bus mounts

Gen Tx

Figure 28

Insulation

Generator

Gen Tx

Insulated Bus mounts

Figure 29

PDA Coupler Installation Guide Appendix D – IPB Installs - 43


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Figure 30

Ground Loop

Figure 31 illustrates the effects of a ground loop in a ISO phase bus.

The dotted line indicates the circulating currents in the ISO phase should it begrounded at both the Generator and Generator Transformer.

The dotted/dashed line indicates the effects of a conduit or metallic pipe that isgrounded and attached to the ISO phase bus.

It should be note that 1000’s of amps could flow and any pipe introducing asecond ground on the ISO phase bus system will eventually melt and causedamage to internal cables.

Potential circulating currents due to grounding atboth ends of IPB – 1000’s amps can flow

GeneratorGen Tx

conduit

Insulation

Generator

Gen Tx

Insulated Bus mounts

Figure 31



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Typical Conduit Runs with IPB Systems

Figure 32 and Figure 33 illustrate typical conduit runs with insulated conduitsupports and an insulated bushing at the connection of the conduit to the ISOphase bus (Figure 35). Note the Conduit is Grounded at the Term box only.

Figure 34 illustrates an alternative method where flexible plastic conduit is usedat the connection between the ISO phase bus and the conduit, and the conduit isnot in a continous run. Insulated bushings are installed to break up the conduitrun, each section of conduit is grounded indididually so as to prevent circulatingcurrents.

NOTE: Both for safety and measurement, the conduit MUST begrounded. It is essential that the coax runs in grounded metalconduit or against a grounded plane to reduce unwanted noise.

Figure 32

Term

Box

Insulated supports& Spacers

Insulated NylonBushing

IPB

Generator



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Figure 33

Term

Box IPB’s mounted oninsulated expansion mounts

Conduit run insulated from IPBas well as ground

Generator

TermBox

Insulated supports

Flexible PlasticConduit

InsulatedSpacers

IPB

Figure 34



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Metal Conduit

Nylon insulated Bushing

Coax Cables

Outer shield of Coax –isolated from Ground and nconnected

ot

GeneratorEnclosure

Figure 35



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Glossary

Terms Definitions

Angle Plate Offsets the coupler at a 45 deg angleBar Half coil, typically roebeled, full coil consists of 1 bottom bar and 1 top bar.

HydroGuardContinuous PD monitoring system using PDA couplers as the sensors with theability to trigger off of operating conditions based on analog inputs

HydroTracContinuous PD trending system using PDA couplers in a double-endedinstallation as the sensors

Cable Coupler Old style 80pF capacitor made from wire shielded high voltage cable

Circuit Rings

/Collector Rings

Copper bus or cable which connects the line coils to the generator terminals.Depending on the machine design, each circuit may have a dedicated ring ormay have multiple circuits on each ring.

Coaxial Cable RG 58 Coaxial cable, normally 152m (500ft) supplied

Coil Multi-turn, full coil

Coupler Pair The two couplers on a given phase which are paired together as C1 and C2

CTs, VTs Current or Potential transformers used to monitor machine parameters.

Differential Install

Typically installed on Hydro machines – Couplers are connected to the linecoils/circuit rings on each circuit in a phase. There must be a minimum of 1m(3ft) of circuit ring on each circuit. Noise separation is done by time pulse timeof arrival.

Directional PDAInstallation

Where there is insufficient circuit ring length, couplers are installed external ofthe unit on the bus (same as a bus installation) but calibrated as a PDA.

EMC Coupler Epoxy Mica Capacitor – 80pF

EMC MountingClamp

Standard two piece clamp used to secure the coupler in place

Feeders, splits Taps on bus bar to auxiliary circuits.

Ground Cable Green 10’ cable used to ground the Iris termination box to a station ground.

Guideline TapeRed silicone rubber tape used for environmental protection – has excellenttracking properties

HV Cable A 2-foot length of HV cable, which connects the HV side of the EMC to thegenerator winding. Requires cutting to length.

Insulated Boot Moulded silicon rubber boot – designed to replace the Sap and Silicone tapes

Line Coils The last coil in a circuit having the highest voltage in the circuit

Mounting block Used to mount 25 kv couplers in any position other than Vertical

PDA IV Instrument required to perform the on line testing

Rise time Time required for a pulse to increase from 10%-90% of its pulse magnitude.

Sap TapeBlack 1.5inch wide HV insulating tape, requires 30% stretch to selfamalgamate.

TGA-P LiteTurbo Generator Analyser – portable instrument to measure PD using PDAcouplers as the sensors.

PDA Coupler Installation Guide Appendix E – Glossary - 48


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Tape Insulation for the EMC

In some circumstances the customer may prefer to use tape insulation as

opposed to the pre-fabricated silicone rubber boot. These materials are suppliedat additional cost OR to be sourced by client.


SAP Tape – 5 cm (2 in)wide++

2 rolls** Self-Amalgamating Polymeric Tape. Black in colour,used to insulate. ROTUNDA 2501

Silicone Rubber Tape –2.5 cm ++

(1 in wide)

2 rolls** Self Fusing – Orange in colour ROTUNDA Protectivecover over SAP tape

Electrical Putty – 5 cm (2

in) wide++

8 strips Electrical Putty to mould around connections to be taped.

Supplied in strips 33 cm (13 in) long

Figure 36

Tooling and materialsrequired to insulate the

EMC with tapes

There are three basic materials as part of the insulation system [Figure 37]:

" Wrapfast that is used to form a cone around the connection to facilitate

taping" Self-almagamating (SAP) tape that provides the dielectric strength

" Silicone rubber (Guideline) tape to provide protection from electricaltracking and some dielectric strength

PDA Coupler Installation Guide Appendix F – Tape Insulation for EMC- 49


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Right angle ring lug

High Voltage Cable

Minimum insulation overlap 1"

Tapes should only cover the first skirt of the EMC

The putty should be formed into a

cone shape

2" wide black SAP tape

Number of layers depends

on the voltage class

2 half-lap layers ofsilicone rubber tape

(Guideline)

Figure 37

" Prior to insulating the EMC, position theEMC on the unit and determine which waythe EMC brackets will be mounted and theposition where the coaxial cable will exitthe EMC in relationship to the EMC

clamps.

Figure 38

" Because of the nature of the HV cableconnection to the top of the EMC, thecable will be offset from the centre andmay influence a preferred orientation withrespect to the coaxial cable. Therefore,when installing the high voltage cable,ensure that the slot for the coaxial cableexit at the bottom of the EMC is orientatedin the right direction.

" Tighten the brass bolt, but do not over tighten, to the point where the lock washerstarts to spread. It is preferable that the HV cable be oriented to come back acrossthe top of the EMC once installed. It is easier to insulate if you can secure thecoupler to a stable surface as shown in Figure 38.

" Warming the wrapfast putty first will soften the material making it easier to form.



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" Apply the electrical putty (wrapfast) aroundthe top connection to the EMC. Theaccompanying photo shows the wrapfastmoulded into a cone shape. This shapecreates a smooth taping surface over top

of the EMC.

" The wrapfast should extend out or close tothe edge of the EMC, but not over theedge. Once the wrapfast has beenapplied, the coupler is now ready forinsulating.

Figure 39

" The first layer of tape to be applied is the SAP tape, which is a stretchable, self-amalgamating tape. This tape requires a 30% stretch to properly bond the tapelayers. The tape comes with a vinyl layer that must be removed during the taping.

" If insufficient stretch is applied, the tape layers will not bond creating a bulky, poorlyinsulated joint. Overstretching will cause thinning or tearing of the tape, reducing theelectrical value of the insulation and causing the tape to “creep” or roll afterapplication.

" The number of layers applied depends on the voltage rating of the machine

Machine Voltage Number of half lap layers

Up to 7 kV 4 layers

Up to 11 kV 5 layers




Figure 40 Figure 41



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" As this is a stretch tape, it is important to “lock” the tape within the topgroove on the EMC to prevent the insulation from rolling over the rim.To lock the tape in the groove, position the tape so that 2/3 of the tapeis inside the top groove of the EMC [Figure 40]. Apply two turns ofinsulation in this position and then continue to tape up the EMC [Figure

41]. Each successive layer of tape must be locked within the topgroove.

" The final step is the application of two half-lap layers of Guideline tape over top of theSAP tape. Start the tape inside the groove,covering all the black SAP tape as shownin Figure 42.

" Guideline tape is self-amalgamating anddoes not require a stretch to bond thelayers. A slight stretch will allow the tape to

lay flat and bond properly. If the tape isstretched too much, the tape will roll ortear, be difficult to apply, and the electricalproperties of the tape will be compromised.

Figure 42

" This Guideline tape, along with

having very good electrical insulatingproperties, also has excellenttracking resistance.

" Once finished, the coaxial cable canbe attached and the EMC mountedon the machine



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25kV EMC Brackets

Due to its weight and length, the largest (25kV) coupler can only be mountedvertically upright, using the standard metal clamping plates. Special (optional)horizontal mounting blocks are used when the 25kV couplers require mounting inany position from the vertical. The blocks may be assembled directly to the unitin the horizontal or suspended positions, or mounted to an angle-mountingbracket.

Horizontal Mounting BracketThe Labadie2 Block was designed forease of retro-fitting existinginstallations where the conventionalIris mounting brackets were used.

While physically larger, the slottedmounting holes are drilled to the samecentres as the conventional steelmounting brackets.

Mounting Kit: 2-piece machinedmounting block, Two clamping bolts, 4mounting bolts and epoxy (not shown).

Selecting Mounting Location

" Temporarily assemble 1 set ofcomponents to be used for layingout the mounting positions for theEMC and drilling the mounting holes

Figure 43

" When selecting location for mounting, ensure that there is sufficient roomfor the mounting block and adherence to all electrical clearances [Section2.4].

2 This specialized mounting block was designed for the Ameren UE, Labadie Power Plant.

PDA Coupler Installation Guide Appendix G –25kV Mounting Brackets - 53


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Assembling the Components

1. Trial fit the EMC couplers to theLabadie Block. Due to machine

tolerances it may be necessary totry several EMC’s in a givenblock to achieve the best fit.Once properly fitted, the EMCshould contact the block in twopositions. The space betweenthe two mounting blocks sectionsshould be equally spaced. Thebottom of the EMC should beflush with the mounting block.

Once the EMC has been paired with theblocks, disassemble and apply a bead ofepoxy around the machine mating surfacesof the block, as shown in figure 2. The epoxyis used to fill the voids where the EMC is notin contact with the Labadie Block.

The epoxy has a working life ofapproximately 20 minutes so prepare theassemblies one at a time.

Match the coaxial cable duct machined in theLabadie Block with the cut–out on the EMC.This is extremely important since there must bea channel for the cable. Once the epoxy sets, itwill be impossible to adjust the base.

Bolt the assembly together applying equalpressure on each bolt. Once tight, the spacingshould be equal on each side and the facesparallel.

Note: When tightening the bolts, only sufficientpressure should be applied so that the EMC cannotbe rotated within the block. Over tightening maydamage the EMC. Loc-ti te must be used.



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After tightening, wipe off the excessepoxy that has been extruded out andallow to set.

If the base of the EMC is not flush withthe bottom of the mounting block, file thebottom of the EMC using a medium fileuntil flush.

Assemble the coaxial cable [Section 4]. A small amount of epoxy can be appliedinside the cutout to secure the coaxialcable in place. The counter sunk boltholes should be filled with epoxy topositively lock the mounting hardware

Insulate the top of the coupler asdescribed in Section 2.5 for the pre-formed boot and 0 for tape insulation.

The assembled coupler is now ready tobe mounted on the unit.



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PDA Coupler Installation Guide

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