The function of arc suppression cabinet

When the circuit short circuit arc grounding, quickly transformed into metal grounding. Metal grounding, non fault phase voltage on the immediate stability of the equipment in the system can run safely in this voltage; because the arc is extinguished, overvoltage is limited to the level of security, fault will not continue to develop. Within the energy index of over voltage energy to reduce overvoltage protector allowed, avoid the explosion of voltage protector; bus voltage is limited at low level, can avoid the excitation ferroresonance overvoltage. Petersen cabinet, is actually in the power system generation method arc grounding is no longer using the traditional consumer the compensation current of arc extinguishing coil, but with the high voltage contactor cabinet bus arc grounding phase, reliable grounding, so as to achieve the purpose of arc extinguishing cabinet. The rise in recent years, the cost is lower than the arc suppression coil, can be The voltage transformer is PT, which is used to collect the voltage value, it is similar to the small transformer, generally the high voltage to low voltage arc suppression and elimination of harmonic line selection and overvoltage protection equipment (arc suppression cabinet)

YHXG arc suppression and harmonic line selection and overvoltage protection devices for 3 ~ 35 medium voltage power system, the product widely used in 3 ~ 35kV neutral point grounding, neutral via arc suppression coil grounding or neutral point connected to a power system with high resistance, of the system in all kinds of overvoltage restrictions, effectively improve the system operation safety and reliability of power supply.

Overview of current arc suppression technology

Occur in (, line voltage of power grid in the grid for a long time, our country 3 ~ 35kV (including 66kV) most of the neutral point grounding operation mode. This kind of single-phase grounding, the non fault phase voltage will rise to the line voltage (UL), but the system remains the same, so China's national standards 3~35KV 66kV grid single-phase fault allowed in a short time with fault operation, thus this kind of grid of all kinds of electrical equipment, such as transformer, voltage / current transformer, circuit breaker, circuit and a device to ground insulation level, should meet the long-term bear line voltage without damage.

The traditional concept that 3~35KV (including 66kV) belong to power in low voltage distribution network, the Internal Overvoltage such power grid in absolute value is not high, so the threat to network security level is not a major factor internal insulation voltage, but atmospheric overvoltage (namely the lightning overvoltage), and thus for a long time to take over voltage protective measures is only to prevent atmospheric overvoltage of equipment damage. Main technical measures only installed in all kinds of lightning arrester, lightning arrester discharge voltage for phase voltage of more than 4 times, according to avoid internal overvoltage design. Therefore, only the protection of lightning damage to effective for Internal Overvoltage does not play any protective effect.

However, operating experience has proved that when the grid development to a certain scale, the internal overvoltage, especially power grid single-phase intermittent arc grounding arc grounding over voltage and under special conditions of ferromagnetic resonance over voltage has become this kind of operation of the equipment and the safety of the power system a threat, which in single phase arc grounding overvoltage is most serious.

With the large-scale technical transformation, our country city and the city of rural power distribution network, have directional cable development in rural areas, the system of capacitance current increases gradually, the problem of arc grounding overvoltage is serious day and night. In order to solve the above problems, a lot of power grid using a resonant grounding mode, namely the design of arc suppression coil in the neutral point of power grid, when the system single-phase arc grounding, fault point for capacitive current is compensated by the inductive current of arc suppression coil is generated, which flows through the fault residual current is reduced, so as to achieve natural extinction. Operating experience shows that although the arc suppression coil on the inhibition of intermittent arc grounding overvoltage has certain effect but in use, also found some problems existing fire extinguishing coil.

(1) due to the stochastic nature of power grid operation mode and the diversification of arc grounding, fire arc suppression coil to the capacitive current is effectively compensated indeed difficult and arc suppression coil only compensate the capacitive current of power frequency, and the actual current grounding not only capacitive current of power frequency, and contains a large number of high frequency current and resistance current, serious when only a high-frequency current and resistive current can sustain the arc continued to burn.

(2) when the grid disconnection, non whole phase, capacitor coupled lines on the same tower non grounding fault, asymmetric power system voltage increased may result in the suppression of arc suppression coil with automatic adjustment controller error occurs in a power system grounding and action, then will be in the grid generated is very high in the displacement voltage, resulting in system in one phase or two-phase voltage rise, many that damage to other devices in the grid.

(3) arc suppression coil has large volume, high cost, high cost and complex installation, which is complicated in operation and maintenance.

(4) with the expansion of the power grid, the arc suppression coil should be replaced, which is not conducive to the future planning of the power grid.

At present on the 3 ~ 35KV power grid to take neutral directlygrounding a few domestic regions to take the grounding through small resistance, while suppressing the arc grounding overvoltage, overcome Petersen coil problems, but at the expense of the reliability of power supply. The single phase grounding a system, artificially increase the short-circuit current of the breaker action, regardless of the nature and the importance of the load, but also all the resection of the fault line can not distinguish the metal or arc grounding. So there is no arc grounding over voltage hazard metallic grounding fault line had been removed, to expand the scope of power outages and due time. Increase the fault current for arc grounding fault point is exacerbated by the loss.