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Neutral point complete equipment-main transformer neutral point gap protection-neutral point grounding combined equipment-gap protection complete equipment

The complete set of neutral point equipment,fully known as the transformer neutral point gap grounding protection complete set of equipment,is primarily used for overvoltage protection of the neutral point of 110KV,220KV,and 330KV transformers.The equipment adopts a protection method involving the parallel operation of zinc oxide arresters and gaps,and is suitable for the neutral points of 110KV,220KV,and 330KV power transformers.It not only protects the neutral point insulation of the transformer from damage caused by lightning overvoltage and power frequency transient overvoltage,but also enables free switching between two different operation modes:grounded operation or non-grounded operation of the transformer neutral point.Baoding Yinuoer Electric specializes in the production of this equipment and is the third manufacturer of gap protection in China.We welcome new and old customers to contact us for business negotiations!

Currently,the neutral overvoltage protection for 110KV and 220KV transformers primarily employs three methods:gap protection,lightning arrester protection,and parallel protection using both a gap and a lightning arrester.

The advantage of gap protection lies in its simple structure,reliability,and minimal operation and maintenance requirements.It can protect transformers under power frequency,switching,and lightning overvoltages.However,its disadvantage is that it is difficult to determine the coordination parameters for such a wide range of protection against the three types of overvoltages.The discharge dispersion is large,the protection characteristics are general,the power frequency continuous current is large,the arc-extinguishing capability is poor,and the gap action can generate chopped waves,which is detrimental to the insulation of the transformer itself.Relay protection is relied on to remove faults,which can result in large and prolonged power frequency zero-sequence current impacting the main transformer during asymmetric grounding faults in the system.

The advantages of lightning arrester protection include a flat volt-second characteristic,low discharge dispersion,excellent protection characteristics,strong ability to cut off power frequency continuous current,and minimal impact on the main transformer.However,it has disadvantages such as being unable to protect against power frequency overvoltage,and it requires protection itself under high power frequency overvoltage,posing a risk of failure.Especially when non-full-phase operation occurs or the system transitions to a neutral-point non-grounded system with single-phase grounding,the steady-state voltage at the transformer neutral point may increase,potentially damaging the valve-type lightning arrester or even causing an explosion.

For this purpose,to ensure reliable operation of the protection system against non-full-phase operation and the system's transition to a neutral non-grounded system with single-phase grounding,a gap must be used to prevent operation under lightning overvoltage.To only protect against lightning overvoltage and dampen the transient overvoltage of the transformer neutral lead-out line during normal network single-phase grounding,a zinc oxide arrester can be selected to ensure the gap does not malfunction.When lightning,power frequency,and switching overvoltages need to be simultaneously protected,a protection method combining a gap or a parallel connection of an arrester and a gap can be adopted.Under power frequency overvoltage,the gap in parallel with the arrester both protects the transformer neutral point and the arrester.

Currently,with the deepening of research on power neutral point protection,the protection method of combining lightning arresters and gap parallel protection is becoming increasingly popular in power systems and industrial and mining enterprises.

Equipment composition:lightning arrester,protective gap,isolating switch,operating mechanism,transformer,base,column,etc