文档介绍：10kv电缆配电网消弧自动补偿系统设计
摘要
电力系统中性点的接地方式是一个非常综合的技术问题,它与电网电压等级、电网结构、绝缘水平、供电可靠性、继电保护、过电压保护、通信干扰(电磁环境)、接地装置及人身安全都有十分密切的关系。过去我国10kV电网中性点运行方式主要不接地、经消弧线圈接地、经电阻接地和经电抗接地多种运行方式,而大部分城区电网的迅猛发展,特别是架空线路比例的减少和电缆大量釆用,出现了10kV电网中性点经小电阻接地方式。该运行方式先后在许多大城市如广州、上海、北京、珠海等地采用。但经多年的运行,各地普遍认为小电阻接地方式比消弧线圈接地方式的过电压水平要低,但同时反映出的运行状况却存在较大差异。上海、广州等地反映运行状况良好;珠海等地则反映运行状况存在较多的问题,主要是多项供电可靠性指标有所较大下降,且发生多起人身伤亡事件。由于大城市城区的10kV电网本身的特殊性和重要性,因此国内在10kV电网中性点接地方式的选择上出现了较大争议。争议点主要是在10kV电网接地故障的形式、消弧线圈接地的应用范围、两种运行方式供电可靠性的高低、人身安全、通讯干扰和运行维护工作量等诸多方面。
本文提出了配电网中性点新型接地方式为:当发生瞬时性单相接地故障时,利用自动跟踪的消弧线圈实现快速补偿,当发生非瞬时性单相接地故障时,能正确选出故障线路并跳闸。提出了髙短路阻抗变压器式可控电抗器的基本结构和原理,用该原理研制成功的髙短路阻抗变压器式自动快速消弧系统。具有伏安特性线性度优良、响应速度快、电流由零到最大都能无级连续调节、补偿效果好、对系统适应性强等优点。是实现新型接地方式比较理想的设备。
根据赣州地区10kV配电网的发展水平、电网结构特点,从长远的发展观点,建议选用经自自动跟踪补偿控制消弧线圈接地方式为益。
关键词: 10kv配电网;中性点接地方式;消弧线圈;自动跟踪补偿
10kv cable work arc pensation system design
ABSTRACT
The problem about neutral-point-grounding mode is an all-around technical problem which associated with not only power system reliability,insulation coordination, ic interference, but assault safety.
In China, the neutral grounding modes of the involved of none grounding, grounding by arc suppressing coils, resistance grounding or reactance grounding in the past. With the development of civic work, low resistance grounding mode was used to restrain the over voltage, particularly in Guangzhou, Shanghai, Beijing,and Zhuhai etc. It was reported that the over-voltage level of low resistance grounding mode is lower than that of arc suppressing coil mode, but the operation caried out the other way. At substations in Guangzhou and Shanghai it was found that the low resistance grounding mode is essful. But in some areas,such as Zhuhai, substations grounding with low resistance revealed some problems, including power supply reliability rapidly dropping, transmitting line often tripping; and person safety being interiorly the grounding mode selection of work was disputed, which mainly focused on the fault form of ground