亳州干式变压器：消弧电抗器的结构及注意事项

消弧电抗器的结构及注意事项 　　
中性点不接地系统发生单相接地时，非故障相电压升高为线电压，流经故障点的电流等于3倍每相电容电流。故障点的电流较大，产生的电弧不易熄灭，有时会扩大为相间短路。为此，常在系统中性点加装消弧电抗器，用电感电流补偿电容电流，使故障电弧迅速熄灭。当6kV电网大于等于30A，10kV电网≥20A，35kV电网≥10A时，就应装设消弧电抗器。
消弧电抗器的结构：消弧电抗器的外形和单相亳州干式变压器相似。内部实际上是由一只具有带间隙的分段铁心绕以线圈构成的。由于铁心带有间隙，所以感抗值较稳定，可得到较大的电感电流。电抗器设有若干抽头，以便在一定的范围内，分级调节电感的大小。消弧电抗器有一个电流互感器和一个电压测量线圈。
消弧电抗器的安装地点应考虑到，在任何运行方式下断开1—2条线路时，大部分电网不致失去补偿，同时可以保证电网主要部分的消弧电抗器过补偿运行。因此，不应将多台消弧电抗器集中安装在电网的一处，且尽量避免电网只装一台消弧电抗器。
另外，并不是任何一台亳州干式变压器的中性点都能接消弧电抗器。在选择装消弧电抗器的亳州干式变压器时，一方面要考虑和消弧电抗器串联的亳州干式变压器的阻抗，另一方面还要考虑因接入消弧电抗器而使亳州干式变压器过载的条件。消弧电抗器的电流是通过亳州干式变压器绕组的。因此，需注意以下几点：
1）对Yd绕组的亳州干式变压器，因有三角形联结绕组的存在，会产生抵消零序电流安匝的环流，所以亳州干式变压器不会受到任何不利的影响。对心式亳州干式变压器，接于中性点的消弧电抗器的大容量主要受到温升的限制。如果消弧电抗器的容量不超过亳州干式变压器额定容量的50%，那么即符合亳州干式变压器2h过载30%的规定；对Yyd联结的三绕组亳州干式变压器，消弧电杭器的容量应不超过亳州干式变压器任一绕组的容量。
2)对Yy联结的三相心式亳州干式变压器，可接消弧电抗器，但其容量受到零序电压降及外壳零序磁通损失的限制，消弧电抗器的容量应不超过亳州干式变压器额定容量的20 %—25%。
3)对Yy联结的壳式三相亳州干式变压器或者单相亳州干式变压器组，因其零序阻抗大，这种亳州干式变压器的中性点不要加装消弧电抗器。
4)在运行巡视时，要检查油温，油位是否正常，油色有否发黑。套管、隔离亳州干式变压器，绝缘子有否污损破裂、引线应牢固、接地良好。吸湿器硅胶未变色，气体继电器窗明且未渗油。消弧电抗器正常运行时无声音，系统出现接地时有“嗡嗡”声，但应无噪声。
5)运行中一但发生下列异常情况，应设法切除消弧电抗器：防爆门破裂且向外喷油，严重漏油、油位计已不见油位，且响声异常或有放电声；套管破裂放电或接地；消弧电抗器着火或冒烟；温度或温升超过极限值；分接亳州干式变压器接触不良严重；接地引线折断，隔离亳州干式变压器严重接触不良或根本不接触。
(5)消弧电抗器的调整，消弧电扰器应采用过补偿运行方式。这样，当电网因故障或其他原因断开某些线路时，不致引起串联谐振，产生危险的过电压。一般不宜采用欠补偿运行。脱谐度不宜超过10%，中性点位移度一般不大于15%（对35kV系统为3kV)。在中性点位移超过正常相电压的20%(即4000V)时，或通过消弧电抗器的电流大于5A时，禁止拉合消弧电抗器闸刀。
目前已有自动调谐的消弧电抗器。

The structure of the arc reactor and precautions

Neutral point ungrounded system to single-phase, non-fault phase voltage increased as the line voltage, current through the point of failure is equal to three times per phase capacitive current. The point of failure current arcing is not easy to extinguish, sometimes expanded to phase short circuit. For this reason, often installed in the system neutral point arc reactor, inductively current compensation capacitor current, the fault arc quickly extinguished. When 6kV Network is greater than or equal to 30A, 10kV grid ≥ 20A, 35kV grid ≥ 10A, it should be installed in the arc reactor.
Arc reactor structure: the shape of the arc reactor and single-phase transformer. The interior is actually by a band gap segment core around the coil constitutes As the core with a gap, the inductance value is more stable, available larger inductor current. The reactor has a number of taps, so that within a certain range, grading adjust the size of the inductor. The arc reactor coil of a current transformer and a voltage measurement.
Installation location of the arc reactor should take into account in any operating mode, disconnect the 1-2 lines, most of the power grid without losing compensation, while the grid to the main part of the arc reactor over compensation to run. Should not be focus on more than one arc reactor installed in a grid, and try to avoid the grid just installed an arc reactor.
In addition, it is not any one of the transformer neutral point can be connected to the arc reactor. Replace the arc reactor, transformer, on the one hand, to consider and arc suppression reactors in series impedance of the transformer, on the other hand, consider the access arc reactor leaving the transformer overload conditions. The arc reactor current through the transformer winding. Therefore, we need to note the following:
1) Yd winding transformer, due to the presence of a delta connection winding will be generated to offset the circulation of zero sequence current ampere-turns, the transformer will not be any adverse effects. The maximum capacity of the heart-type transformers, then the neutral point of the arc reactor is mainly limited by temperature rise. If the arc electrical resistance to control the capacity does not exceed 50% of transformer rated capacity of, then that is, in line with power transformers 2h had contained 30 percent of requirement; Yyd join the three-winding transformers, arc power Hang device's capacity should not exceed the transformer any of the winding capacity.
2) on the the Yy link three-phase heart-type transformers can be connected arc reactor, but its capacity is the limit of zero sequence voltage drop and shell zero sequence flux loss, the capacity of the arc reactor should not exceed the rated capacity of the transformer 20% -25%.
3) Yy-coupling shell-type three-phase transformer, or single-phase transformer unit, because the zero sequence impedance, the transformer neutral point not to the installation of the arc reactor.
4) in the inspections of the run, you want to check the oil temperature, oil level is normal, whether black oil color. Casing, isolating switches, insulators whether defaced rupture, lead should be a solid, well grounded. The breathers silicone is not color, gas relay windows and no oil leakage. The arc reactor during normal operation no sound, system grounding, "buzzing" sound, but there should be no noise.
5) run, but the following exceptions, should seek the removal of arc reactor: rupture of blast doors and out injector, a serious oil spill, oil level gauge has not se邮 箱：1262980066@qq.comen the oil level and abnormal sound or sound of the discharge; sets tube discharge or ground rupture; arc reactor fire or smoke; temperature or temperature rise exceeds the threshold value; tap poor contact serious; ground lead break isolation switch serious bad contact or no contact.
(5) elimination of the adjustment of the arc reactor arc electrical interference compensation run. Thus, when the grid is disconnected due to failure or other reasons some lines will not cause series resonance, resulting in a dangerous overvoltage. Generally should not be used undercompensation run. Off Degree not more than 10% displacement of the neutral point is generally not more than 15% (35kV system 3kV). More than 20% of the normal phase voltage (ie, 4000V) in the neutral point displacement current through the arc reactor is greater than 5A, prohibit the Lahti arc reactor knife.
At present, the automatic tuning arc reactor.

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