由于故障电流微弱、电弧不稳定、故障形态多样，以及受到消弧线圈补偿电流影响等原因，小电流接地电网单相接地（小电流接地）故障选线问题一直未得到很好的解决。目前绝大多数故障仍然通过人工拉路的方法确定故障线路，给故障查找和修复带来了极大的不便。

通过深入研究故障暂态特征及暂态信号利用方式，科汇公司在小电流接地故障选线技术上取得重大突破，提出了利用故障暂态信息的选线原理，并成功研制出了基于故障暂态信号的小电流接地故障选线及监测装置。

与传统利用故障稳态信息的方法相比，暂态选线技术具有检测可靠、成功率高、适应面广的特点。与需要安装专用一次设备或者需要消弧线圈等一次设备配合的方法相比，暂态选线技术又具有安全可靠、施工便利的优点。即，其实现了高选线成功率和高安全性等诸多特点的完美结合。

该系列产品先后获得多项国家发明专利和国家创新基金支持，是国家重点新产品。在选线原理和装置结构上均达到国际领先水平，能够满足不同条件下对选线技术的要求。

系统主要功能

l小电流接地故障线路和故障相选择

lTV断线自动检测

l永久保留故障记录，可保留不少于10000条故障录波数据

l选线结果可通过多种方式上报主站

l通过对接地故障分析统计，实现线路绝缘状况监测和预警

l支持对接地故障线路跳闸和重合闸

l支持显示故障记录和故障录波波形

l与智能配电终端配合完成故障区段定位功能

l可灵活组建小电流接地故障综合信息系统

主要技术特点

选线成功率高

l暂态信号幅值大（过零故障仍有明显的暂态过程），检测可靠性、

 灵敏度高

l剔除了暂态信号中不支持选线要求的分量，原理更先进

l利用自适应算法基于多种方法选线，互为补充，结果更可靠

l不受不稳定电弧影响，且弧光接地和间歇性接地时检测更可靠

适应性广

l可适用于不接地、经消弧线圈接地和经大电阻接地系统

l可适用于架空线路、电缆线路或架空电缆混合线路

l零序电流可通过普通零序CT获得，也可通过三相CT合成

l可适用于母线并联运行、环网供电等特殊运行方式

l可适用于各种等级变电所，也适用于开闭所

l不受系统规模和线路结构变化影响，可满足配网自动化需求

安全性高

l被动式选线，只需接入母线PT信号和出线零序CT信号

l不需向电网注入其他信号，对一次系统无任何影响

l不需要安装专用耦合设备和其他高压设备，不停电安装及维护

装置设计先进

l采用16位高速AD，对暂态信号准确、可靠采样

l可分析出极性反接，信号断线等非正常情况对选线的影响

l对于CT、PT变比不统一和极性错误可通过软件配置补偿

l选线结果可通过103、CDT或符合IEC-61850标准的规约上报调

 度或控制中心

功能扩展方便

l利用瞬时性故障相关参数对线路绝缘状况提出预警

l对故障线路准确判定后实施跳闸

l与智能配电终端配合完成故障区段定位功能

l各选线装置可组件小电流接地故障综合信息系统（接地故障分析

 主站）

技术指标

l选线准确率：金属性接地故障100%   考虑高阻接地故障综合选线>95%

l可检测瞬时性接地故障的最短持续时间：1ms

l监测出线数：监测出线数：每台XJ-200装置可监测2段母线共28路出线，可实现对28路出

 线进行跳闸和重合闸闭锁动作（装置扩展数量不受限制）

l系统存储容量：可永久保留故障信息，可保留超过10000条故障录波数据

l电源输入：220±10％V AC/DC

l装置尺寸（宽、高、深）：482.6mm×177mm×275mm

l屏体机柜尺寸（可选）：2260mm×800mm×600 mm

                                       2360mm×800mm×600 mm

 Shandong Kehui Power Automation Co., Ltd. was originally known as Zibo Kehui Electric Co., Ltd. and the private Zibo Kehui Electric Instrument Research Institute founded in 1993 and 1991 respectively.
    Shandong Kehui Power Automation Co., Ltd. develops, produces and sells power cable fault monitoring equipment, power distribution automation equipment, railway power automation and switched reluctance motor drive system. It has an Automation Department, a Switched Reluctance Motor Department, and a subsidiary of Jinan R&D Center and Jinan Kehui Automation Engineering Co., Ltd., domestic offices in Shanghai, Guangzhou, Chengdu, and Xi’an, etc. and overseas offices in London and Seattle. It has over 260 employees now, of whom 60% have a bachelor degree or above. In 1998, it was certified to ISO9001 Quality Management System. It is a high-tech enterprise designated by the Department of Science & Technology of Shandong Province and one of the “Top 10 Excellent Software Enterprises” rewarded by the Department of Information Industry of Shandong Province.

    It is headquartered in Zibo, a famous industry city of middle Shandong. Shandong Kehui Science and Technology Park covers an area of over 120 mu, with exquisite environment and complete facilities. It has power automation labs, power monitoring labs, and switched reluctance motor labs equipped with complete facilities for development, production and inspection, good network and communication ability, sophisticated office and logistics facilities, providing a broad space for further development. Kehui Jinan R&D Center with a building area of 4,000 square meters, located in Jinan High-tech District Software Park, will attract more talented people to join in Kehui and strengthen Kehui in developing and introducing new technologies.

    Shandong Kehui Power Automation Co., Ltd. has been taking technology innovation as the lifeline of its development. A technology development team of high quality led by Doctor Xu Bingyin was established including 5 doctors, and more than 30 masters. Kehui, well-known for its specialty in power cable fault monitoring, is China’s only manufacturer providing complete solutions on fault monitoring and positioning of power cable, distribution wire, and transmission wire. The T-series power cable fault detection instruments, XJ-series distribution wire fault monitoring and positioning system, and XC-series traveling wave ultrahigh-voltage transmission wire fault ranging system developed have reached international advanced level, and solved the faults positioning problem that has obsessed power departments for a long time. Winning the 2nd Prize of National Technology Invention, and the Award for Progress in Science and Technology of Shandong Province, the products occupy over 50% domestic market share, and have been exported to Britain, Italia, Africa, South Asia and South America, etc. In 1994, for the first time in China, Kehui developed power system synchronous clock for receiving GPS satellite signal, which has been applied to over 6000 stations and factories in China. The PZK-series distribution automation terminal unit, developed by Kehui in 1997, with the new technology of embedded system adopted, has reached international advanced technology level, and over 10,000 sets have been put into operation. As the first company who started the railway power automation business in China, the KH-series railway power dispatching automation system and distribution substation automation system developed by Kehui has been introduced to over ten railway administrations in China. The SRD-series switched reluctance motor drive system, developed by Kehui in 2005, passed the verification performed by Yao Fusheng and Lu Bingheng, academicians of China Academy of Engineering, and Li Haifa, Professor of Tsinghua University, and was considered to be international advanced. The SRD-series product, with good energy-saving effect, low starting current, small starting torque, solid structure and high reliability, is a major breakthrough of drive system, and has a good market prospect.

    In the business principle of “People Orientation, Customer Supremacy, Continuous Innovation, Constant Improvement”, Shandong Kehui Power Automation Co., Ltd. strives to provide customers with better products as well as sincere, thoughtful, professional and timely service. While developing business, Kehui strengthens the team construction, basic management construction, and enterprise culture construction, and has built up efficient and normalized management mechanism with international standards, to achieve sustainable and healthy development of the company through the growth of organization and the enhancement of management level.
    In future, Kehui people will continuously carry forward the pioneering spirit of “Struggle, Innovation, Improvement”, expand the business scale, enhance management level, and promote the competitiveness comprehensively, to build Kehui as a power monitoring and automation enterprise with strong economic strength and outstanding innovation ability and make Kehui first-class in China and internationally influential.