The synchronization device is a device used to control motors, generators or other electrical equipment. It judges whether the two sides of the circuit breaker meet the synchronization conditions, so as to decide whether to perform closing and grid connection. By adjusting the amplitude, frequency, phase, etc., the equipment can be connected to the grid safely. It collects the electrical quantity information on both sides of the circuit breaker in real time, performs calculation and comparison, determines whether the current state allows closing, and identifies the optimal closing time.

△ Relaystar-Z70 Handheld Analog-Digital Integrated Relay Protection Tester

The synchronization test function module of the Relaystar-Z70 Handheld Analog-Digital Integrated Relay Protection Tester can test the operating voltage, operating phase angle and operating frequency of synchronization relays or synchronization devices, and conduct automatic quasi-synchronization adjustment tests. The following describes how to use the Relaystar-Z70 to complete the preventive test of the synchronization device and verify whether it meets the synchronization closing conditions.

Test Wiring

1) Voltage Wiring

Single-phase voltage: Connect the side to be synchronized to UA of the Relaystar-Z70, and connect the system side to Ua.

Three-phase voltage: Connect the side to be synchronized to UA, UB, UC, and connect the system side to Ua, Ub, Uc.

2) Input Contact Wiring

Connect the "boost", "buck", "up-frequency", "down-frequency" output signals of the synchronization device to the input contacts A, a, B, b of the Relaystar-Z70 respectively; connect the closing action output signal to the input contact R of the tester. Short-circuit the other ends of the above output signals of the synchronization device and connect them to the common terminal (red terminal) of the input contacts of the tester. If each output contact of the protection is an active contact, connect the positive power supply of each output contact to the common terminal of the input contacts of the tester.

Test Method for Synchronization Voltage Value

Open the main interface of the Relaystar-Z70 and select the synchronization test module.

First, set the voltage V1 of the side to be synchronized to 90V, which does not meet the synchronization conditions. Set the frequency F1 and phase Φ1 of the side to be synchronized to meet the synchronization conditions—for example, set the frequency close to that of the system side (e.g., 49.9Hz) and set the phase arbitrarily. Meanwhile, set a specific voltage step size.After starting the test, press the voltage increase/decrease buttons step by step to adjust the voltage until the synchronization device operates.

During the test:

If the frequencies on both sides are unequal, switch to the "test data" interface and wait for the angle in the "side to be synchronized" and "difference value" columns to change continuously. If you press the "synchronization indicator" button, you can observe in the pop-up synchronization window that the voltage vector of the side to be synchronized is rotating continuously and its length is changing.

If the frequencies on both sides are equal, the voltage vector of the side to be synchronized will not rotate, but only change in length.

When the three synchronization conditions (voltage, frequency and phase angle) are all satisfied—that is, the voltage vectors of the side to be synchronized and the system side are close to the allowable range—the synchronization device will send an output signal. The tester will record the voltage difference, frequency difference and phase angle difference at the moment of operation.

Note: The frequency of the system-side voltage is a fixed value of 50Hz, the phase angle is 0°, and the default voltage is 100V, which can be adjusted.

The above is the test method for the synchronization voltage value; other synchronization-related tests can be completed in this module.When conducting the synchronization test, press the start button of the synchronization device to initiate the test. Before the test, find the synchronization start signal input terminal on the device and lead out two wires. After starting the test, short-circuit the two wires to activate the synchronization device. In addition, some synchronization devices allow setting a synchronization time limit. If the synchronization process exceeds this time limit during the test, the device will block the closing operation of this synchronization and send an alarm signal. In this case, press the synchronization start button again or short-circuit the above two wires to activate the synchronization device once more.