Manual Closing No-Voltage Integrity Test Procedure
Scope of application: Manual closing test for no-voltage synchronizing logic in integrated protection devices; this can verify local/remote control logic, synchronizing test tap logic, synchronizing opening time interlocking logic, and other related logic functions.
I. Objective of the Study
Verify the correctness of the no-voltage logic during manual closing of the testing device: in local control mode, when the no-voltage control word is activated during manual closing, the protection reliably opens the closing circuit once the side under test meets the no-voltage condition; when the device is switched to remote control mode, the synchronizing closing logic is reliably locked out; if the side under test is under voltage and the synchronizing opening time limit is exceeded, the closing is locked out, and a synchronizing closing failure alarm is reported; additionally, verify that the device correctly stores records of the closing action and events related to the synchronizing failure.
II. Pre-test Preparations
(1) Device setpoints, control words, and pressure plate settings
Quasi-synchronous voltage differential lockout: 10 V; quasi-synchronous frequency differential lockout: 0.5 Hz; quasi-synchronous acceleration lockout: 1 Hz/s; permitted closing angle: 15°; closing lead time: 0.2s; inherent phase-angle difference: 10°; synchronization opening time: 40s; synchronization phase: Phase A; PT open-circuit lockout; synchronization: Off; manual synchronization check: Off; manual synchronization check with no voltage: On; synchronization test busbar: energized/de-energized as required
(2) Secondary Wiring
Voltage circuit: connect the tester's UA, UB, UC, and UX terminals to the device's Ua, Ub, Uc, and UL terminals, respectively; closing circuit: connect the device's closing-output contacts to the tester's input terminals to capture the closing-action signal; input circuit: connect the hand-operated closing input and the local/remote control position inputs to the tester in accordance with the drawings.
(3) Precondition Requirements
The device is set to local control mode, the circuit breaker is in the open position, and the duration of the circuit breaker's open position remains greater than 30s.
III. Stepwise Trial Items
Project 1: On-site mode; the test pressure plate is energized simultaneously; the side under inspection remains de-energized; reliable closing is verified.
Confirm the status of the control word: perform simultaneous disconnection during manual closing and simultaneous energization during manual closing without voltage; then energize the synchronization test plate. The device remains in local control mode, and the switch is in the open position for a duration exceeding 30s. Tester output: Ua = 57.74 V ∠ 0°, Ub = 57.74 V ∠ -120°, Uc = 57.74 V ∠ 120°, Ux = 0 V ∠ 0°; all three-phase currents output 0 A. Close the manual closing switch and energize the synchronization input; observe the device status. When the no-voltage condition is met, the closing output operates correctly.
Project 2: On-site mode; simultaneously withdraw the test pressure plate; the side under inspection has no pressure; verify reliable closing.
Remove the test pressure plate from the同期 test; keep all other set values, control words, and circuit breaker position states unchanged. Repeat the voltage output and manual synchronization input/output operation steps described in the previous item, observe the device, and ensure that the closing output operates correctly once the no-voltage condition is met.
Project 3: Remote control mode; simultaneously energize the test busbar, ensure that the side under inspection has no voltage, and verify the closing interlock.
Apply the test pressure plate during the same period of operation, switch the equipment to remote-control mode, and maintain the switch in the open position for a duration exceeding 30s. The voltage output of the tester should remain consistent with Item 1; the Ux output should be 0 V, and the manual switch should remain closed during this period. Observe the equipment: the closing outlet should not operate, and in remote mode, the manual closing test should fail due to no voltage present.
Project 4: On-site mode; the side under inspection is energized, exceeding the simultaneous opening time; verify the closing interlock and report a failure in simultaneous timing.
The device returns to local control; the synchronizing test pressure plate is engaged, and the switch remains in the open position for more than 30s. The tester outputs: Ua = 57.74 V ∠ 0°, Ub = 57.74 V ∠ -120°, Uc = 57.74 V ∠ 120°, and Ux = 57.74 V ∠ 0°; the three-phase current output is 0 A. The manual closing function is activated, and the system remains in the closed state for more than 40s beyond the prescribed synchronizing closing time. Upon observing the device, the closing output does not operate, and the device issues a [Synchronizing closing failure] alarm.
Project 5: Event Record Verification
After all test items have been completed, enter the device event menu and verify that the closing action event and the synchronization failure event are stored correctly and that SOE records can be viewed normally.
IV. Criteria for Determining Test Compliance
First, in local control mode and when there is no voltage on the side under inspection, the device can correctly close regardless of whether the synchronizing test closing plate is energized or de-energized; second, in remote control mode and under equivalent no-voltage conditions, the closing circuit remains reliably inactive; third, when there is voltage on the side under inspection, the device locks out the closing operation after the synchronizing opening duration exceeds 40s and correctly sends a synchronizing closing failure signal; fourth, both the closing action and the synchronizing failure generate corresponding event records, which are complete and readily available for inspection.
V. On-site Precautions
Before the test, install the device's maintenance pressure plate to prevent the closing circuit from being inadvertently triggered; UL, i.e., the Ux terminal, indicates the voltage on the side under inspection for the absence of voltage and serves as the core variable of this test; do not confuse it with the busbar voltage; the simultaneous opening timer begins timing from the moment the timer is switched from the closed state to the open state; once the test has fully concluded, restore the device's original pressure plate, control word, and setting values.
💡 A note at the end
I have compiled the complete commissioning documentation for the hand-coupled synchronization test without voltage and synchronized testing, as well as a checklist of common pitfalls; it includes the test procedures for each synchronization method. If you need it, feel free to send me a private message.
