How does General Used Current Transformer protect the power system?

1. Provide fault current signal
1. Overcurrent protection:
When an overcurrent fault (such as short circuit, overload, etc.) occurs in the power system, the primary current will increase sharply. General Used Current Transformer converts the large current on the primary side into a small current on the secondary side in proportion for use by the overcurrent protection device.
When the protection device detects that the secondary current exceeds the set threshold, it will act quickly to cut off the fault circuit to prevent equipment damage and the expansion of the accident.
2. Quick-break protection:
Quick-break protection is a fast-acting protection method used to quickly cut off the fault. General Used Current Transformer can quickly respond to changes in primary current and transmit the fault current signal to the quick-break protection device.
When it is detected that the fault current exceeds the action value of the quick-break protection, the protection device immediately acts to cut off the fault circuit.
2. Realize differential protection
1. Transformer differential protection:
In transformer differential protection, General Used Current Transformer is installed on the high and low voltage sides of the transformer to collect current signals on both sides respectively.
The protection device determines whether there is a fault by comparing the magnitude and phase of the current on both sides. If the difference between the currents on both sides exceeds the set value, it means that there is a fault inside the transformer or in the lead, and the protection device trips.
2. Bus differential protection:
Bus differential protection is used to detect bus faults. General Used Current Transformer is installed at the outlet of each connecting element (such as line, transformer, generator, etc.) on the bus to provide current signals to the bus protection device.
When a bus fault occurs, the protection device determines the fault location based on the current signal provided by each current transformer, and trips all the connecting elements on the faulty bus.
3. Grounding protection
1. Single-phase grounding fault detection:
In a neutral point grounding system, General Used Current Transformer can be used for grounding protection. When a single-phase grounding fault occurs, the grounding current flows into the earth through the grounding device.
General Used Current Transformer detects the change in grounding current, and the protection device determines the fault type based on the magnitude and phase of the grounding current, and trips.
4. Overload protection
1. Prevent equipment from overload operation:
Overload protection is used to prevent electrical equipment from being damaged due to long-term overload operation. The General Used Current Transformer converts the current signal on the primary side into a small current on the secondary side for use by the overload protection device.
When the current exceeds the rated current of the equipment and lasts for a certain period of time, the protection device will operate, send out an alarm signal or cut off the power supply.
V. Failure protection
1. Circuit breaker failure detection:
Failure protection is a backup protection method. When the main protection is activated and the circuit breaker fails to operate correctly for some reason, the failure protection determines whether the circuit breaker has failed by detecting the current signal provided by the General Used Current Transformer.
If the circuit breaker failure is detected, the failure protection will operate, expand the power outage range, cut off the faulty equipment, and prevent the fault from further expanding.
VI. Distance protection
1. Fault distance judgment:
The distance protection uses the current and voltage signals provided by the General Used Current Transformer and the voltage transformer to calculate the electrical distance between the fault point and the protection installation.
When the fault distance is detected to be within the protection range, the protection device will operate and cut off the faulty line.
VII. Protect the safe operation of the power system
1. Isolate the primary high-voltage circuit:
General Used Current Transformer isolates the primary high-voltage circuit from the secondary low-voltage circuit to ensure the safe operation of the measuring and protection equipment.
Prevent high-voltage electricity from breaking through the measuring equipment or protection device to ensure the safety of personnel and equipment.
2. Improve the reliability of the protection device:
General Used Current Transformer can provide accurate and stable current signals to ensure that the protection device can correctly determine the fault type and location.
Improve the reliability of the protection device and reduce false operation and refusal to operate.