Ground Fault Temporary Overvoltages in MV Networks: Evaluation and Experimental Tests
Ground Fault Temporary Overvoltages in MV Networks: Evaluation and Experimental Tests
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DOI：
10.1109/tpwrd.2012.2192456
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发表时间：
2012-05
影响因子：
4.4
通讯作者：
A. Cerretti;F. Gatta;A. Geri;S. Lauria;M. Maccioni;G. Valtorta
中科院分区：
文献类型：
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作者：
A. Cerretti;F. Gatta;A. Geri;S. Lauria;M. Maccioni;G. Valtorta
在具有隔离中性点的大型径向中压网络中，单相接地故障可能会导致大量的暂时过电压（tov），甚至超过3pu。相接地。谐振中性点接地将这些过电压限制在1.8 p.u.，但可靠的接地装置故障可能会触发高达2.4 p.u.的tov。本文介绍了意大利20kv ENEL配电网络的接地故障研究。在中性点接地安排的大参数范围内的分析评估，包括隔离中性点和ENEL谐振接地与并联电阻，作为2.4 p.u的证据。tov中性点隔离，1.8 p.u.谐振接地，超过2.0 p.u.部分补偿。给出了在同一网络中分段的地面故障记录，分析预测与实验测试之间表现出良好的一致性。测试证实，在隔离中性点的情况下，tov超过2.3 p.u.，有时演变成跨国故障（可能解释了不可预见的电缆故障率），并且ENEL中性点接地实践在抑制这些tov方面的有效性。
Single-phase-to-ground faults may cause substantial temporary overvoltages (TOVs) in large radial medium-voltage networks with isolated neutral, even over 3-p.u. phase to ground. Resonant neutral earthing limits these overvoltages to 1.8 p.u. but credible earthing apparatus failures might trigger TOVs up to 2.4 p.u. This paper presents the ground fault study of an Italian 20-kV ENEL Distribuzione network. Analytical evaluations in a wide parametric range of neutral earthing arrangements, include isolated neutral and ENEL resonant earthing with parallel resistance, as evidence of 2.4-p.u. TOVs with isolated neutral, 1.8 p.u. with resonant earthing, and more than 2.0 p.u. with partial compensation. Recordings of ground faults staged in the same network are presented, showing excellent agreement between analytical predictions and experimental test. The tests confirm TOVs of more than 2.3 p.u. with isolated neutral, sometimes evolving into cross-country faults (possibly explaining unforeseen cable fault rates), and the effectiveness of the ENEL neutral earthing practices in suppressing these TOVs.