EXERCISE 7

INTRODUCTION TO LVSB DESIGN

EXERCISE 7

INTRODUCTION TO LVSB DESIGN LEARNING OUTCOME

1. To familiarize & identify the main parts of the Low Voltage Switch Board.

2. To read and interpret circuit and schematic diagram.

3. To locate wiring referred to the drawings.

CONTENT

7.1 THEORY

This is a standard industrial LVSB, specially adapted to function as a training unit. It enables switchgears, instruments and protective gears used in industrial switchboard to be demonstrated and their functions explained. It is an excellent practice unit for students to study its circuitry, dismantle and reassemble component parts, rewire, fault simulations and trouble-shooting. Unit is mobile with heavy duty castors. Compartment doors/covers are hinged and can be opened manually by finger-operated screws. TECHNICAL SPECIFICATIONS: Input: 240/415VAC, 35A, 3 phase, 50Hz. Output: Power = 1 x 100A TPN (MCCB). = 2 x 60A TPN (MCCB). = 1 x 30A TPN (MCCB)

Figure 7.1: Low Voltage Switch Board. Main Switchboard

i. 3 x Current Transformer chamber for Kwh meter, 150/5A, class CTs. ii. 1 x 640A, TPN, 415V, 50Hz, draw out Air Circuit Breaker iii. 1 x combined Over Current and Earth Fault Relay with digital display. iv. 1 x 0-500V Voltmeter c/w selector switch. v. 1 x 0-150A Ammeter (with Maximum Demand Indicator) c/w selector

switch. vi. 1 x Power Factor meter. vii. 3 x Indicating Light (Incoming). viii. 3 x Indicating Light (Outgoing). ix. 8 x 6A Instruments Fuse. x. 4 x Current Transformer 150/5A, class 10P10, 15VA. xi. 4 x Current Transformer 150/5A, class 1, 15VA. xii. 1 x Heater c/w thermostat & switch. xiii. 1 x Electronic surge protection device. xiv.4 x Bus Bar 640A TP&N.

A. Automatic Power Factor Correction Panel

i. 1 x 6 step Digital power Factor Regulator. ii. 6 x 5kvar, 415V, 3 phase Capacitor Bank. iii. 1 x 100A TPN MCCB. iv. 1 x 0-500V Voltmeter c/w selector switch. v. 6 x Indicating Light. vi. 6 x 6A Instruments Fuse. vii. 6 x 15A TPN MCB. viii. 1 x Ventilation fan. ix. 7 x Busbar Coupler Panel

B. Construction

i. Physical Size : Approx. 2230H x 1375 x 760D in mm. ii. Console : Galvanized sheet steel. iii. Finish : Baked epoxy powder in grey. iv. Mounting : Unit is mobile with heavy duty castors. v. Marking : Engraved labeling plate.

C. INPUT POWER REQUIREMENT :

240/415VAC, 35A, 3 phase via isolators.

D. OUTPUT :

i. 1 x 100A TPN MCCB, c/w shunt trip coil, & Earth Fault Relay. ii. 1 x 60A TPN MCCB, c/w shunt trip coil & Earth Leakage Relay. iii. 1 x 60A TPN MCCB. iv. 1 x 30A SPN MCCB.

E. OPERATING PROCEDURES :

i. To operate, first ensure that all breakers and switches are in the ‘OFF’ positions.

ii. Energize unit via input cable to input socket. Indicating lights colored red, yellow and blue mounted directly above the panel should indicate that unit input is available.

iii. Charge the closing springs of Air Circuit Breaker until the charging indicator shows ‘Charged’. The closing springs are charged by pumping the charging.

iv. Handle with the full stroke 10-13 times. Then push the close button. The Air Circuit Breaker should be heard on closing. The on-off indicator show ‘On’ and the charging indicator show ‘Discharge’. Indicating lights colored red, yellow and blue mounted at the top centre of the unit should indicate that unit bus-bars are energized.

v. Check supply voltage by operating the voltmeter selector switch. Check supply frequency as indicated by the frequency meter. Readings should be as follows :

Voltmeter : 415VAC between phases (approx.) Frequency : 50Hz.

vi. Output (Single Phase – Lighting). Connect any appropriate single phase load and switch ‘ON’ the desired circuit breaker(s).

vii. Output (Three Phase – Power) Connect any appropriate 3 phase load and switch ‘ON’ the desired circuit breaker(s) at the power DB.

viii. Meters With the single phase and three phase loads in the circuits, ammeters power factor meter and maximum demand indicator should be in operation.

ix. Emergency Trips Isolators are provided to simulate typical remote emergency trips. The Air Circuit Breaker should de-energized the supply to the bus-bars.

x. Shut Down/Open Breaker/Trip Breaker Push the ‘Off’ button and breaker is tripped or opened. The ACB should be heard on opening. The ‘On-Off’ indicator shows ‘Off’. Next switch ‘Off’ the isolator at the distribution boards.

7.2 EQUIPMENT LIST 7.2.1 Low Voltage Switchboard 1 unit ACTIVITIES Activity 1 (Switchboard Design) :

Figure 7.2: Low Voltage Switch Board.

1. Label the Switchboard panel with a complete labeling of the components. 2. Based on the component figures given in attachment and schematic

diagram in Figure 7.3 until 7.5. Explain the function of all components and compile the technical specification/model/brand required for the LVSB in Table 7.1 below:

Table 7.1: Component list of switch board panel.

No Component Brief Technical

Spec. Model / Brand Function Qty

1 2 3 4 5 6 7 8 9 10

Kwh Meter Indicator Light Heater Air Circuit Breaker IDMTL (Overcurrent & Earth Fault Relay) Ammeter (analogue) Power Factor Meter (analogue) Voltmeter (analogue) Earth Fault Relay Earth Leakage Relay

V = I Ratio = Freq = V = 240 Volt I = 14 mA Freq = 50 Hz V = 240 Volt I = 3A Freq = 50 Hz V = In= Freq = V = CT Ratio = Freq = I(scale)= CT Ratio = Freq = V = I = Freq = V(scale) = Freq = V = CT Ratio = Freq = V = CT Ratio = Freq =

Telemecanique ZBV-M6 Daiichi Denko CH 24080

1 6 1 1 1 1 1 1 1 1

Figure 7.3: Schematic Control Diagram For Main Incoming.

Figure 7.4: Schematic Control Diagram For Outgoing Feeder C/W Earth Fault

Relay.

Figure 7.5: Schematic Control Diagram For Outgoing Feeder C/W Earth Leakage

Relay.

Figure 7.6: Schematic Control Diagram of Power Factor Correction Capacitor

Bank. 3. Record three(3) different videos with detail explanations of : i- The Switchboard panel with a complete explanation of the components. ii- The schematic diagram of Figure 7.3. iii- The schematic diagram of Figure 7.4 and 7.5. Give the link of the recorded video in the lab report.

Activity 2 (Questions)

1. Briefly explain the function of Power Factor Correction Capacitor Bank.

2. Briefly explain the function of Moulded Case Circuit Breaker (MCCB).

3. Briefly explain the function of Ammeter Selector Switch and Voltmeter Selector switch.

Activity 3 (Conclusion)

Please elaborate the detail conclusion from the experiment.

REFERENCE

1. Paul Gill; Electrical Power Equipment Maintenance & testing; Taylor & Francis (1998).

2. Robert W. Seaton; William H. Ubert; Switchgear & Control Handbook (3th Edition); McGraw Hill (1998).