EXERCISE 1

INTRODUCTION TO LVSB DESIGN

INTRODUCTION TO LVSB DESIGN LEARNING OUTCOME

1. To familiarize & identify the main parts of the Low Voltage Switch Board.(C3-LO2)

2. To read and interpret circuit and schematic diagram. (P5-LO5)

3. To locate wiring referred to the drawings. (A2-LO9)

CONTENT

1.1 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 1 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 Breakeriii. 1 x combined Over Current and Earth 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.

Figure 1.1: Low Voltage Switch Board.

3 x Current Transformer chamber for Kwh meter, 150/5A, class CTs.1 x 640A, TPN, 415V, 50Hz, draw out Air Circuit Breaker 1 x combined Over Current and Earth Fault Relay with digital display.

500V Voltmeter c/w selector switch. 150A Ammeter (with Maximum Demand Indicator) c/w selector

1 x Power Factor meter. 3 x Indicating Light (Incoming). 3 x Indicating Light (Outgoing).

s Fuse. 4 x Current Transformer 150/5A, class 10P10, 15VA. 4 x Current Transformer 150/5A, class 1, 15VA. 1 x Heater c/w thermostat & switch. 1 x Electronic surge protection device.

xiv.4 x Bus Bar 640A TP&N.

3 x Current Transformer chamber for Kwh meter, 150/5A, class CTs.

Fault Relay with digital display.

150A Ammeter (with Maximum Demand Indicator) c/w selector

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.

1.2 EQUIPMENT LIST 1.2.1 Low Voltage Switchboard 1 unit ACTIVITIES Activity 1 (Switchboard Design) :

Figure 1

1. Draw the Switchboard panel, compile a complete list of components

required for the LVSB under the following headings:

Table 1.1: Component list of switch board panel.

No Component Brief Technical

Spec.

.2.1 Low Voltage Switchboard 1 unit

Activity 1 (Switchboard Design) :

Figure 1.2: Low Voltage Switch Board.

Draw the Switchboard panel, compile a complete list of components required for the LVSB under the following headings:

.1: Component list of switch board panel.

Brief Technical Spec.

Model / Brand

Function

.2.1 Low Voltage Switchboard 1 unit

Draw the Switchboard panel, compile a complete list of components

Qty

2. Using a Multimeter, trace and sketch circuit/schematic/wiring diagrams of the Switchboard. Compare your dia1.6, 1.7 and 1.8).

3. Read and interpret circuit and schematic diagrams. 4. Labeling all the internal components of the LVSB referred to the drawings

given.

Figure 1

Figure 1

Using a Multimeter, trace and sketch circuit/schematic/wiring diagrams of the Switchboard. Compare your diagrams with those given (Figure 1

Read and interpret circuit and schematic diagrams.

the internal components of the LVSB referred to the drawings

Figure 1.3: Internal parts (front).

Figure 1.4: Internal parts (rear).

Using a Multimeter, trace and sketch circuit/schematic/wiring diagrams of grams with those given (Figure 1.5,

the internal components of the LVSB referred to the drawings

Figure 1.5: Schematic Control Diagram For Main Incoming.

.5: Schematic Control Diagram For Main Incoming.

Figure 1.6: Schematic Control Diagram

.6: Schematic Control Diagram For Outgoing Feeder C/W Earth Fault Relay.

For Outgoing Feeder C/W Earth Fault

Figure 1.7: Schematic Control Diagram For Outgoing Feeder C/W Earth Leakage

.7: Schematic Control Diagram For Outgoing Feeder C/W Earth Leakage Relay.

.7: Schematic Control Diagram For Outgoing Feeder C/W Earth Leakage

Figure 1.8: Schematic Control Diagram of Power Factor Correction Capacitor

Activity 2 (Questions)

1. Briefly explain the function of kilowatt hour meter (kWh).

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

3. Briefly explain the function of Ammeter Selector Switch.

REFERENCE

1. Paul Gill; Electrical Power Equipment Maintenance & testingFrancis (1998).

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

.8: Schematic Control Diagram of Power Factor Correction Capacitor Bank.

Briefly explain the function of kilowatt hour meter (kWh).

Briefly explain the function of Moulded Case Circuit Breaker

Briefly explain the function of Ammeter Selector Switch.

Paul Gill; Electrical Power Equipment Maintenance & testing; Taylor &

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

.8: Schematic Control Diagram of Power Factor Correction Capacitor

Briefly explain the function of Moulded Case Circuit Breaker

; Taylor &

Robert W. Seaton; William H. Ubert; Switchgear & Control Handbook (3th