In accordance with the power grid operation reliability requirements, for power supply systems with two or more incoming lines, when a line loses power and cannot restore supply within a short period, the system shall switch to another line to resume power supply. 110kV automatic transfer switching is divided into two types: incoming line BATS and sectional bus BATS.

 

Incoming Line BATS

Under normal conditions, one of the two power incoming lines on the busbar is in service while the other is on standby. When the in-service line trips due to a fault and causes busbar voltage loss, the BATS device operates to automatically switch in the standby line.

 

Sectional Bus BATS

Under normal conditions, both busbar sections are energized and the sectional circuit breaker is open, with the two busbar sections serving as backups for each other. When one busbar section loses voltage due to an incoming line fault, the BATS device operates to close the sectional circuit breaker.

 

The following describes the sectional bus BATS test for the NR Electric PCS-9653 BATS device using the Relaystar-7000 Digital-analog Integrated Relay Protection Tester.

1 Test Wiring

The PCS-9654 is a BATS device for smart substations, which adopts direct sampling for current and voltage, and GOOSE communication for switch input and output signals. Therefore, the wiring shall follow the conventional method for current and voltage connections, and optical fibers shall be connected for GOOSE signals.

 

△ Wiring Diagram

After completing the wiring, enter the IEC61850 Settings of the Relaystar-7000, set the output mode to power amplifier output, and connect the optical fiber signals to the GOOSE output ports of the BATS device. Configure the GOOSE parameters and map the trip output of Circuit Breaker DL1 (Line B) to Output 1, the trip output of Circuit Breaker DL2 (Line C) to Output 2, and the output of the sectional circuit breaker to Output 3. After the configuration is completed, the IEC61850 Settings can be closed.

2 Setting Values and Control Words

For sectional bus BATS, attention shall be paid to the time setting values. In addition to the time settings, enable the GOOSE Receive Soft Press Plate and the BATS Function Soft Press Plate in the function soft press plate configuration.

Setting Item	Value
Voltage Loss on Busbar & Master Trip Signal Transmission Delay	0.3s
Delay for Tripping the Main Supply Unit	2.0s
Circuit Breaker Trip Waiting Delay (Dynamic Time)	1.0s
BATS Success Judgment Waiting Delay (Dynamic Time)	2.0s
BATS Function Soft Press Plate	1 (Enabled)

3 Test Procedure

 

After completing the wiring and device setting configuration, set the state sequence of the Relaystar-7000 as follows:

1. Initial State

Set both busbar sections to be energized, and both incoming lines to be energized. At this time, Circuit Breaker DL1 (Line B) is closed (Output 1 = Closed), Circuit Breaker DL2 (Line C) is closed (Output 2 = Closed), and the sectional circuit breaker is open (Output 3 = Open). Set the trigger mode to key trigger and wait for the BATS device to complete charging.

 

2. Voltage Loss on Line B & Busbar Section I
   Set the incoming line B and Busbar Section I to lose voltage. At this time, the protection device trips Circuit Breaker DL1, but the position of DL1 remains closed (Output 1 = Closed). Circuit Breaker DL2 remains closed (Output 2 = Closed), and the sectional circuit breaker remains open (Output 3 = Open). Set the trigger mode to time trigger with a duration longer than the setting value, which is set to 3s.

 

3. Voltage Restoration on Busbar Section I
    

   

   
   
   Set Line B to remain without voltage, and restore normal voltage to both busbar sections. At this time, the BATS device issues a command to close the sectional circuit breaker, but the sectional circuit breaker DL3 remains open (Output 3 = Open). Circuit Breaker DL1 is open (Output 1 = Open), and Circuit Breaker DL2 remains closed (Output 2 = Closed). Set the trigger mode to time trigger with a duration longer than the setting value, which is set to 2s.

 

4. Sectional Circuit Breaker Closing & BATS Success

Set both busbar sections to maintain normal voltage and Line C to remain energized. At this time, the sectional circuit breaker DL3 is open (Output 3 = Open), Circuit Breaker DL1 is open (Output 1 = Open), and Circuit Breaker DL2 is closed (DL2 = Closed). Setthe time trigger duration to 3s. At this point, the BATS operation is successful.

 

4 Test Results

This BATS device test is implemented based on GOOSE output for smart substations. For BATS devices in conventional substations, the switch input/output signals shall be connected to the trip outputs of the three circuit breakers respectively to complete the test. If the test requires linkage with actual circuit breakers, manually close DL1 and DL2 and open DL3. This allows the BATS test to be completed without connecting the physical switch signals.