13.8kv CORONA SOUND

A corona sound was continuously coming from 13.8 kV Bus Tie side.

The complete showdown was taken for investigation. Incomer and Bus tie breakers are 3500A capacity rated and Fan is provided for reduce the heat developed in the breaker during full load condition.

The Fan wire was slightly touch the bus.

HIGH VOLTAGE CABLE TEST

1.CABLE TEST MANUAL

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2. CABLE CROSS BONDING CONNECTION

 DRAWING

When current is flow through the cable a induced current will develop in the cable sheaths. This induced current will oppose the cable current. The cross bonding connection is used to neutralized the induced current. The cross bonding connection is explained in the above drawing. Cable sheath is terminate in various places and connected as cross connection 'R' sheath to "Y" sheath and 'B' sheath to 'R' sheath through resistors. Three phase voltage is applied in one end of cable and other end of cable is grounded. Short circuit current will flow through the cable and induced current in sheath will be measured by clam meter. If the current is zero in all three phase and cross connection ok .

3. FIELD TEST REPORT

1. ELECTRICAL TEST 

2. HV TEST 


Related Photos 

CABLE SHEATH CROSS BONDING CONNECTION

HV TEST READING FOR 115KV XLP CABLE TEST 

CABLE CONNECTION POINT FROM GIS 

CABLE CONNECTION POINT FROM INSIDE GIS 

CABLE CONNECTION POINT FROM CABLE SIDE

Generator Field current controller. During cable short circuit test ( Cross bonding verification) generator current increase and voltage decrease. This equipment used to control the output generator voltage by control the generator field current.

This equipment used for low voltage level cables. Very low Frequency ( VLF) method of HV test.

                                                 SEC STANDARD FOR CABLE HV TEST  

 

                                             

LINE CHARGEING & CHARGING CURRENT

Substation 2 is energized from Substation -1. The current measured in Sub -1 side is 350 Amps in both Line differential relay and Metering panel.

The current measured in Sub -2 side is 270 Amps in Line differential relay and 350 Amps in Metering panel.

The difference in the primary current in both side relays due to underground cable in the line.

Relay measure the line current and cable charging current separately.

RED 670 -ABB will shows both current in the measurement display.

Micom 546 consider charging current as a differential current.

One End current 

Remote End current 

Differential and Charging current 

Note : 

The power direction

Import should be (-ve)
Export should be (+ve)

If Micom 546 shows Export MW as a -ve value go to MEASURE'T SETUP - MEASUREMENT MODE and SET '0'