In the neutral point non-effectively grounded system, a neutral point is drawn through the grounding transformer, and the neutral point is grounded with the nonlinear resistor. The system operates normally and the neutral point is not grounded. When an intermittent arc or permanent arc ground fault occurs in a circuit of the system, the neutral point voltage of the grounding transformer rises, the non-linear resistance is turned on, and the zero-sequence loop will flow through a zero-sequence current amplified to the ground. It is sent to the main controller through the fault loop acquisition unit, and the dynamic capture monitor is used to monitor the real-time dynamic monitoring of the three-phase voltages of the entire network system A, B, and C, and to monitor the change of the voltage and the phase angle of the system to judge and analyze the fault of the system. Mutually.
When intermittent arc overvoltage occurs in the system, the voltage of the non-faulty phase can increase to 1.5-3.5 times, which seriously affects the normal operation of the system, causing the system to generate instantaneous intermittent overvoltage and develop into arc. The control system detects the voltage of the whole network After the change, let the whole network overvoltage suppressor be put into use to absorb various overvoltages and intermittent arc overvoltages generated by the system to protect the system and maintain the safe operation of the system.
When the intermittent arc overvoltage capacity is large, and it is converted into a single-phase fault grounding or a permanent single-phase grounding fault, the control system monitors the changes in the system and exits the voltage suppressor of the entire network, and switches the arc suppression input to eliminate the system arc. When the arc of the system is eliminated, the voltage suppressor of the whole network is rewashed and put into operation to eliminate the peak overvoltage of the system, maintain the parallelism of the system voltage, and stably ensure the safety of equipment power supply.
When the system has overvoltage fluctuations, high-resistance grounding or metallic grounding, instantaneous or permanent grounding faults, the system will generate low-frequency, medium-frequency or high-frequency oscillations to cause primary and secondary resonance, which seriously affects the stability of measurement and protection signals. In severe cases, the voltage transformer will be burnt, and the voltage transformer will be tripped. When the system has a primary or secondary resonance, the control system will eliminate the secondary resonance, and at the same time, send an instruction to turn on the instantaneous switch to eliminate the primary resonance and ensure the safe operation of the system.