What is the function of the arc suppression coil according to the operation regulations of the arc s

Arc suppression coils. It is a compensation device used for small current grounding systems. When a single-phase ground fault occurs in the system.

, the arc suppression coil generates an inductive current to compensate for the ground capacitance current.

The current passing through the grounding point is lower than the current required to generate an intermittent arc or maintain a stable arc, which plays a role in eliminating the arc at the grounding point.

It can be seen that the arc suppression coil has a certain role in overvoltage protection.

When a single-phase grounding fault occurs in the three-phase line, the inductance current is generated to compensate for the capacitance current of the line to the ground, so that the fault will not cause continuous arcing, so that the fault range will be expanded, and the safety and reliability of the power supply system will be improved.

As the name suggests, the arc suppression coil is arc extinguishing, and the arc suppression coil that adopts manual turn fixed compensation in the early stage is called the fixed compensation system. The arc suppression coil belongs to the moving core structure, and the arc suppression coil is widely used in the resonant grounding system of LOKV-6KV level. Due to the oil-free tendency of substations, many arc suppression coils below 35 kV are now dry cast types.

The function of arc suppression coil is to prevent the occurrence and expansion of arcs, protect equipment and extend the life of equipment, ensure the safety of personnel, and improve the reliability of the power system.

1. Prevent the occurrence and expansion of arcs.

The main function of arc suppression coil is to quickly detect and cut off arc faults that occur in the power system or electrical equipment, and reduce the damage caused by arcing. When an arc occurs in the system, the arc suppression coil can quickly detect the arc signal and separate the arc area from the power supply by means such as control switches, so as to prevent the further development and expansion of the arc.

2. Protect the equipment and prolong the life of the equipment.

Arc is a high-energy, high-temperature discharge phenomenon, which will produce strong ionization, thermal radiation and shock waves and other harmful filial effects, causing serious damage to power equipment. The function of the arc suppression coil is to quickly cut off the arc current when the arc occurs, and take corresponding measures, such as reducing the voltage and limiting the current, to protect the equipment from arc damage and prolong the service life of the equipment.

3. Ensure the safety of personnel.

Arc accidents are a high-risk scenario that can cause serious personal injury such as fire, **, electric shock, etc. The trace widening function of the arc suppression coil is to quickly cut off the current when the arc occurs, and reduce the damage degree of the arc.

The arc suppression coil reduces the hazards of thermal radiation, ionizing radiation and shock wave of the arc to the surrounding environment and personnel, and provides a safer working environment. The arc suppression coil can also provide the right value of overvoltage and overcurrent protection, so that the staff can be safely evacuated in the arc accident, reducing the injury and loss caused by the accident.

4. Improve the reliability of the power system.

Arc faults in the power system can lead to equipment failures, power outages, or short-circuits in the grid, which can have a serious impact on normal power supply and production activities.

The function of the arc suppression coil is to reduce the failure rate and fault duration, and ensure the reliability and stability of the power system. By quickly detecting and cutting off arc faults, arc suppression coils can reduce the scope and duration of faults on the power system and improve the reliability of system operation. Arc suppression coils are widely used in power systems and electrical equipment to improve the safety and reliability of the working environment.

Function: When a single-phase grounding fault occurs in the power grid, the arc suppression coil provides inductance current compensation to reduce the fault point current to less than 10A, which is conducive to preventing the arc from re-igniting after crossing zero and achieving the purpose of arc extinguishing; Reduce the probability of high amplitude overvoltage and prevent further expansion of accidents; When the arc suppression coil is properly tuned, it can effectively reduce the probability of arc grounding overvoltage, minimize the thermal damage effect of the fault point and the voltage of the grounding grid.

The arc suppression coil structure is characterized by electronically controlled stepless continuous adjustable arc suppression coil, full static structure, no moving parts inside, no contact, large adjustment range, high reliability and fast adjustment speed. By applying DC excitation current to change the magnetic resistance of the iron core, thereby changing the reactance value of the arc suppression coil, it can adjust the inductance value with high voltage at the speed of milliseconds.

When the compensation system is single-phase grounded, the continuous operation time of the arc suppression coil should generally not exceed 2h.

In order to expand the range of compensation current adjustment, the gear of the on-load adjusting arc suppression coil is set to 9 18 gears, and the compensation current ratio can reach 5:1. The increase in the adjustment gear reduces the interval current difference and improves the compensation accuracy, with the detuning degree being less than 5% and the residual current being less than 5A.

The controller samples and calculates the relevant detection parameters of the power system in real time, and when a single-phase grounding fault occurs, the microcomputer controller can quickly respond to the fault within 10ms and deal with it accordingly, and the response to the fault is improved from "seconds" to "milliseconds".

The on-load switch adjustment time of the general arc suppression coil in China is 12 15 seconds, and we use a unique "switching technology" to improve the on-load adjustment time to 6 7 seconds, so that the adjustment speed is not doubled.

The controller adopts 80C196 or PLC or industrial computer to control the Songzao as the core (for users to choose), with fast operation speed, high integration, strong anti-interference ability, multi-channel acquisition input signal and output instruction are fully isolated, and the outlet is controlled by dual addresses. Eliminate measurement errors and malfunctions caused by interference.

The software system realizes automatic re-entry when disturbed, and the redundancy check and BCH code verification are used for important data, and the data chaos caused by interference can be automatically recovered, which completely solves the problem of "crash".

An arc suppression coil is a type of inductive coil with an iron core. It is connected between the neutral point of the transformer (or generator) and the ground to form an arc suppression coil grounding system. During normal operation, no current passes through the arc suppression coil.

When the power grid is struck by lightning or single-phase arc grounding, the neutral point potential will rise to the phase voltage, and then the inductive current flowing through the arc suppression coil and the capacitive fault current of the single-phase grounding cancel each other out, so that the fault current is compensated, and the residual current after compensation becomes very small and not enough to maintain the arc, so as to extinguish itself. In this way, the ground can be quickly eliminated without causing overvoltage.

The function of the arc suppression coil is that when a single-phase grounding fault occurs in the power grid, the capacitance current flows through the fault point, and the arc suppression coil provides inductor current to compensate, so that the fault point current is reduced to below 10A, which is conducive to preventing the arc from re-igniting after crossing zero, achieving the purpose of arc extinguishing, preventing the probability of high amplitude overvoltage, and preventing the further expansion of the accident.

Arc suppression coil controller.

When the arc suppression coil is properly tuned, it can not only effectively reduce the probability of arc grounding overvoltage, but also effectively suppress the radiation value of overvoltage, and also minimize the thermal damage effect of the fault point and the voltage of the grounding grid. The so-called correct tuning, that is, the inductor current is grounded or equal to the capacitance current, and the degree of detuning v is used to describe the degree of tuning.

The neutral point is grounded by the arc suppression coil, that is, an inductive arc suppression coil is connected between the neutral point and the earth. When a single-phase grounding fault occurs in the power grid, the grounding current is greater than 30A, and the arc generated often cannot self-extinguish, resulting in an increase in the probability of arc grounding overvoltage, which is not conducive to the safe operation of the power grid. To this end, the inductance current of the arc suppression coil is used to compensate for the capacitance current to the ground, so that the current passing through the fault point can be reduced to the range of self-extinguishing arc.

Through the operation of the arc suppression coil no-load tap-changer, it can achieve over-compensation operation within a certain range, so as to reduce the grounding current. This allows the grid to run continuously for a period of time, which in turn improves the reliability of the power supply.

Generally, there are three different modes of operation for arc suppression coil compensation, namely undercompensation, full compensation, and overcompensation.

Undercompensation: The inductor current after compensation is less than the capacitance current.

Overcompensation: The inductor current after compensation is greater than the capacitor current.

Fully compensated: The inductor current after compensation is equal to the capacitance current.

When fully compensated, a high voltage is felt by the arc suppression coil due to series resonance, regardless of the size of the asymmetric voltage. Therefore, it is necessary to avoid the occurrence of the fully compensated operation mode, and use the overcompensated mode or the undercompensated mode, but in fact, the overcompensated operation mode is generally adopted, and the main reasons are as follows:

When an undercompensated power grid fails, it is prone to high overvoltages.

During the normal operation of the undercompensated power grid, if the three-phase asymmetry is large, there may be a large ferromagnetic resonance overvoltage. This overvoltage is caused by ferromagnetic resonance of the undercompensated arc suppression coil (its WL>1 3WC0) and the line capacitance 3C0. If the overcompensated operation method is adopted, this ferromagnetic resonance phenomenon will not occur.

Power systems tend to evolve and expand, and the grid's ground capacitance will increase accordingly. If overcompensated, the original arc suppression coil can still be used for a period of time, at most from overcompensated to undercompensated operation, but if the original undercompensated operation mode is used, the capacity must be compensated immediately as soon as the system develops.

Because the inductive current flows through the grounding point during overcompensation, the voltage recovery speed of the fault phase after arc extinguishing is slow, so the grounding arc is not easy to rekindle.

When overcompensation is used, the reduction of the system frequency can only temporarily increase the degree of overcompensation, which is no problem during normal operation; Conversely, if undercompensated, the system frequency decreases to bring it close to fully compensated, resulting in an increase in the neutral displacement voltage.

In the past, when Huatian Electric Power did the test, this is to avoid the series resonance that occurs after the line trips, the arc suppression coil should be overcompensated, but when the capacity of the compensation equipment is insufficient, the under-compensation operation can be used, the detuning degree is 10, and the general current does not exceed 5 10A