Neutral point grounding protection equipment Neutral point earthing resistance complete set Small/low current earth-fault line selection device Includes: 1.Transformer neutral point grounding resistance cabinet 2.Generator neutral point grounding resistance cabinet 3.Low-voltage grounding resistance cabinet 4.Transformer neutral point intermittent earth fault protection complete set 5.Small current grounding fault line selection device

Transformer neutral point grounding resistance cabinet

In a cable-powered system, the grounding capacitor current is large. In order to achieve the impact and requirements on the reliability of equipment operation, equipment insulation and protective measures, the neutral point grounding through the resistor can limit the fault current to a moderate size. On the one hand, the relay protection has sufficient sensitivity and selectivity. At the same time, it can only cause local minor damage to the fault point, limit the transient overvoltage to less than 2.6 times the normal line-to-neutral point voltage, prevent the arc from re-ignition, avoid the arc grounding overvoltage to damage the main equipment and expand the accident. At the same time, the resistance damping has a significant effect on preventing ferromagnetic resonance overvoltage.

Generator neutral point grounding resistance cabinet

When a single-phase grounding occurs in the generator circuit of a power plant, and the fault current reaches a certain value, it may cause the occurrence of "intermittent" arc grounding over voltage to have specific "critical" conditions, which cause the generation of arcing grounding over voltage. The withstand voltage level of the generator is weak, and its insulation is easily damaged. If the grounding fault current is too large, the core of the generator will be burnt, and a higher mechanical pressure will be applied to the generator and its circuit.

Therefore, high-resistance grounding is usually used at the neutral point of the generator. When single-phase grounding occurs in its circuit, arc grounding overvoltage is limited to reduce burns to the iron core and reduce mechanical pressure on the generator and its circuits.

Low-voltage grounding resistance cabinet

The low-voltage grounding resistance cabinet is a complete set of resistors for grounding in 0.22KV~0.66KV low-voltage systems. In order to improve the power supply quality of 0.66/0.38/0.22 (KV) low-voltage power systems and reduce equipment outages caused by grounding faults, the low-voltage power system in the main plant of the power plant should use high-resistance grounding, which not only avoids to trip immediately when the phase is grounded not necessary, reduce the probability of burnout when the electrical equipment is running when fuses are used as protective appliances.

After a neutral point grounding resistance cabinet installed, when non-metallic grounding occurs, the current flowing through the grounding point and the neutral point is significantly reduced by the influence of the grounding point resistance, and the non-fault phase voltage rise is also significantly reduced. Zero sequence voltage value is about half that of a single-phase metallic grounding.

Transformer neutral point intermittent earth fault protection complete set

Transformer neutral point intermittent earth fault protection complete set adopts zinc oxide arrester and intermittent parallel operation protection mode, which is suitable for the neutral point of 110KV, 220KV, 330KV power transformers, it not only can protect the transformer neutral point insulation from damaging by lightning overvoltage and power frequency transient overvoltage, but also realize the free switching of two different operation modes of transformer neutral grounding operation or un-grounding operation.

Transformer neutral point intermittent earth fault protection complete set (main transformer neutral point grounding combined equipment) is widely used in power plants and power stations such as thermal power, hydropower and wind power, substations of the state grid corporation, coal mining, steel metallurgy, petrochemical and other large industrial and mining enterprises.

Chongqing Enrich Engineering and Technology Co., Ltd

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