母线PT开关柜内为什么需要装一次消谐装置呢?
因为在6-35KV中性点非有效接地电网中的电压互感器有以下两个相关问题需解决:
Because voltage transformers in 6-35KV neutral non-effectively grounded power grids have the following two related problems to be solved:
1、电压互感器的铁磁谐振产生的过电压常使设备内绝缘击穿、外绝缘放电,且常因事故处理不及时或事故扩大而造成大面积停电;
1. Overvoltage caused by ferroresonance of voltage transformer often causes insulation breakdown and external insulation discharge in equipment, and often causes large-scale power outage due to untimely handling of accidents or enlargement of accidents.
2、电网中的弧光接地使电压互感器频频烧毁。使用消谐器可有效地解决上述问题:消除或阻尼PT非线性励磁特性而引起的铁磁谐振过电压,这种谐振过电压会导致系统相电不稳定;能有效抑制间隙性弧光接地时流过压变绕组的过电流,防止压变烧毁;限制系统单相接地消失时在压变一次绕组回路中产生的涌流,这种涌流会损坏压变或使压变熔丝熔断;当系统发生单相接地后可较长时间保护压变免受损坏。
2, the arc grounding in the power grid makes the voltage transformer burn down frequently. The above problems can be effectively solved by using harmonic eliminator: eliminating or damping ferroresonance overvoltage caused by PT non-linear excitation characteristics, which will lead to electrical instability of the system; effectively suppressing overcurrent of overvoltage transformer windings in gap arc grounding to prevent voltage variation from burning out; limiting the disappearance of single-phase grounding of the system The inrush current generated in the primary winding circuit of the voltage transformer will damage the voltage transformer or cause the voltage transformer fuse to fuse. When the system is single-phase grounded, the voltage transformer can be protected from damage for a long time.