4160 & 480 Volts Switchgear Testing Types

Perform Ductor Test Randomly on The Main Bus Joints

Check The Annunciation Indications for Alarms (Transformers And Relays) and Remote Indications , Check Target LED Indication on The SEL Relay.

Partial Differential Function Check 4160 Switchgear.

Partial Differential Function Check 480 Switchgear.

Wrong Partial Differential Function Check.

Tie Breaker Lock Out Functional Check at Less Than 80 % Bus Voltage.

This function happens when any one of the buses voltage is zero and the other healthy incoming source voltage is less than 80 % thus the signal will be passed from healthy incomer SEL relay to dead bus incomer SEL relay through ether net cable to block the Out Put command “102- U/V Xfer “ for Tie Breaker Closing.

Note: if ether net cable is not healthy , this transfer will take place even the voltage is less than 80 % .so please check this cable cautiously.

Transformer CT Stability Test ( Applicable to 34.5 /4.16 KV , Above 3.75 MVA Transformer )

1 . 4.16kv Breaker side line A ,B, C Bus-Bar shorted
2 . Apply primary voltage with respective Required secondary current.
3 . Check Stability current in SEL-787.
4 . SEL-787 0 Current its ok stability.
5 . SEL-751A will the display transformer secondary current.

Check The Breaker Open Operation When Main and Tie Breaker Closed Manually And Bus Voltage is Dead. All Breaker Remain on Close stat.

1. Synchronized
2. Parallel MTM
3. Fail line or bus (PT )voltage
4. All Breaker remain on closed

Check The Breaker Tripping On Relay Protection Functions.

Check ATS and Synchronization Operation

ATS Functional Test

Synchronization Check

Transformer Function Checks (OTI, WTI, PRV, Rapid Pressure, LLG, Fan Operation By Activating The Electromechanical Devices.

Transformer Function Checks (OTI, WTI, PRV, Rapid Pressure, LLG, Fan Operation By Activating The Electromechanical Devices.

Applicable 5 MVA Above

63 – Rapid Presser Rise Relay Device.
49T – Dial Hot Spot Thermo Meter.
26Q – Thermometer , fan start 70 ⁰C & Alarm cont. 80° C.

71Q – Liquid Level Gauge , Alarm cont. ( low level ).
63P – Pressure Relief Device Alarm.

Note :- 63X RELAY power supply 125V DC from SEL-787 Circuit.

63X – Rapid Presser Rise Relay Panel TO Trip 86T (SUDDEN PRESSURE).

45M – Hydra C1 Monitor

GAS HI . GAS HI- HI , SYSTEM Failure

45 S – Hydran 201Ti Transmitter

26Q – Thermometer , fan start 70 ⁰C & Alarm cont. 80° C

71Q – Liquid Level Gauge , Alarm cont. ( low level )
63P – Pressure Relief Device Alarm.

27S-1 – Loss of fan power supply contactor coil 208 volts AC
43 -1 – Fan switch AUTO/ Manual
4 -1 – Fan contactor 120V AC
8-1 – Fan power Breaker , 6amp , 2 pole
8-2 – Hydran power Breaker 6 amp , 1 pole (if applicable)

BR/DR – Breather Drain

SH-1 – Space Heater
HS-1 – Heater Switch
TH – Humidstat /Thermostat

Earth Pit Resistance Check for Main Switchgear Body.

Battery Charger And Battery Bank Commissioning And load Test By Vendor.

Following topics are helpful to understand for Installation, commissioning and testing of Switchgear.