RD4000 Product Training

RD4000

Locator Product Training

Phill Hembery

Technical Support Engineer

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RD4000 Product Training

Think SAFETY at all times !



A safe system of work has four basic elements:

• Planning the work• Plans• Cable and pipe locating

devices• Safe digging practices



Result of a cable strike.

Burns to the back of a man’s

leg.



Result of a cable strike.

Burns to a man’s upper

body.



• Locators do not locate cables or pipes, they locate the magnetic field around the line.

• The magnetic field is created by an alternating current flowing along the line.

• This magnetic field forms a cylindrical shape around the line and is known as the ‘signal’.

• Principle known as electromagnetic induction.

What are we locating ?



Two Types of Location Methods

Passive:

These occur naturally on lines and pipes as an effect of 50/60Hz electric power energy or VLF energy.

• The main purpose is for avoidance• Quick• No need for a transmitter• Relatively easy



Passive Location

• 50/60 Hz signals induced into ground.

• These signals travel along metallic cables or pipes.

• Enables most, but not all power cables to be located passively.

POWER



Passive Location

• Very low frequency (long wave) radio waves from distant transmitters.

• Ground provides return paths for energy.

• Metallic lines form preferred paths.

• Signals strong enough to be located in most parts of country.

RADIO



Passive Location - Practical Implications

• Cannot be identified - same signal may appear on any conductor.

• If the line is live at high voltage and load switched off, there is no current flow.- No magnetic field so no detectable signal.but it remains a potential danger.

• Single phase cables generally easy to locate, 3 phase cables canbe difficult to locate.- High voltage are better balanced and cancel their fields.- Radio mode valuable complement to Power mode.

• All passive signals can change without warning.



Active:

A signal produced by a transmitter and actively applied to a pipe or cable that can be located and traced with a receiver.

• The main purpose is for tracing and identifying• Measuring depth• Measuring current• Confirmation



Active signals - Connection



Active signals - Induction



Active signals - Signal Clamp



Peak Response

• The response is related to the orientation of the aerial core relative to the field direction, it is also related to line direction.

• This type of aerial gives position and direction information.

• Gives peak or maximum response.

Horizontal aerial - peak response

Horizontal aerial - peak responseHorizontal aerial - peak response

Horizontal aerial



Null Response

• The null or minimum signal is easier to detect than a peak response.

• However, it is more prone to interference and therefore less accurate.

• No direction information.• Good for cross checking peak

mode accuracy.

Vertical aerial



Low Frequency

• Less likely to bleed off.• They carry further than that

of high frequencies.• Also, unlikely to couple onto

other nearby lines.• Will not jump insulated

joints.• Difficult to apply to telecom

cables

High Frequency

• More likely to bleed off.• They do not carry as far as

low frequencies.• More likely to couple onto

other nearby lines.• Easier to apply, especially by

induction.• Will jump insulated joints.

Frequency Selection



• There is an optimum signal frequency for successfully locating and tracing each different type of pipe or cable.

• Surface area of pipe or cable in contact with ground will affect signal leakage to ground.

• Ability of ground to pass current -wet/dry soils.

• Earth return.



Why do we need CM ?

The diagram shows the conventional locator response for the same signal on three adjacent conductors buried at different depths. It is only when CM is used that the correct target line can be identified.

Current Measurement



Any Questions ?



Basic Locating

• The first step to successful locating is to obtain as much information about the site before the locator is even turned on.– Obtain utility maps or drawings– Observe the site– look for physical evidence, i.e. covers, poles, pedestals,

splices etc.



• Set the gain to maximum.• Holding the receiver

vertical at all times, sweep the area with a steady and deliberate motion.

• If necessary adjust the gain to keep the bargraph on scale.

Basic Location - Step 1



• When a signal is detected continue along the search route until signal reduces, then move back to where the signal is strongest, (Peak).




• To determine the direction of the target line, rotate the receiver again looking for the strongest signal.

• The receiver handle will now be aligned with the target line.




• Mark position• Measure depth • Measure current




• Another method of finding buried conductors is to use the induction sweep method.

Active Induction Sweep



• Locators do not find Cables or pipes, they find magnetic fields.

• Therefore anything that affects the magnetic field radiating from a buried conductor will cause a problem or result in some form of error.

- Commonly the main problem is distortion.

Location Problems



• A distorted field appears to come from a different point.

Location Problems



• Field distortion can be checked by verifying the agreement of peak and null responses.

Location Problems



• Null response in an area of congested plant is often useless.

• Peak response is more reliable.

Location Problems



• Reinforcement bars pick up and re-radiate signals.

• Raise receiver 0.5M.• Reduce sensitivity.

Location Problems



• Changes in direction can be a problem.

• If the signal disappears within a short distance, move back to a position where it can be located.

• From this position walk in a circle until the signal is found again.

Location Problems



• Changes in target line depth can cause problems.

• Walk in a circle from the last locatable position until the signal is found again.

• If the signal is not found, turn the receiver gain up until it can be.

Location Problems



• Ends of lines can be a problem.

• Repeat steps for change of direction or change of depth.

• If no signal is found, the target line may have been cut or reached an end.

Location Problems



• Do not measure depth near a bend.

Location Problems



• Do not measure depth near another line.

Location Problems



• Do not measure depth near a change in target line depth.

Location Problems



• Do not try to locate or measure depth too close to an inducing transmitter.

Location Problems



• Plastic or concrete pipes, ducts and drains cannot be located electromatically, unless a tracer wire is inserted or laid along pipe.

• Sonde - self contained transmitter.

• Frequency can be chosen to match receiver.

• Size dictates detection distance - transmitting power.

Tracing Non-Metallic Pipes



• Sondes produce a different field.

• Locator should be in line with sonde

• Locate ghost signals• Depth can be calculated

approximately

A B

D = 0.7AB



• Current Direction recognition is a Radiodetection technique for increasing the information available at difficult locates.

• How does it work?– CD works by comparing

the phase relationship of two frequencies that are applied to the line at the same time.

Current Direction (CD)



• If this signal couples to another adjacent conductor, there will be a change in the phase relationship between the two frequencies.

• The receiver compares the signal with its reference and decides if it matches.

Current Direction (CD)



Fault Find (FF)



RD4000 Accessories



1. On/Off2. Frequency Select3. Gain Paddle4. Depth & Current5. Antenna Select6. Signal Strength7. Antenna Type8. Left/Right Arrows9. CD Arrows10. Line Select11. Sonde Select12. Battery Level13. Numeric Display14. Frequency Selected15. Volume Level16. Radio Mode17. Power Mode18. Volume Level19. Accessory20. EMS Option21. dB Gain22. A Frame

Receiver Display



1. On/Off2. Frequency Select3. Measurement key4. Down key5. Up Key6. Battery Level7. Power Output8. Measurement Display9. Live Cable10. Measurement Indicator11. Induction Mode12. Transmitter Indication13. Clamp Indicator14. Direct Connection15. Text Display16. Frequency display17. Hi Volts18. Volume Level19. External Power

T10 Transmitter Display



Web Enabling Features



Depth Calibration Check



Radiodetection Website - www. radiodetection.com

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