Research and Application of Ground Fault Locating Device for Distribution Network Lines

Power supply companies use digital technology to develop and apply a fully functional fault location system by comprehensively processing and integrating fault alarm data, real-time operational data, offline data, grid structure, equipment parameters and many other information on the distribution network.

1 Background

The power supply company under the jurisdiction of 95 10kV lines, in 2017 due to fault tripping caused by the grid eight events 43, an average of 0.45 / article, while the average time to find the fault event 136 minutes, the line fault outage has seriously affected the reliability of power supply and power supply service capacity. 2018 Weinan Power Supply Company stipulates that the distribution network eight grid events are strictly controlled within 14 times, the production management of distribution networks Requirements are higher, and in this regard, the Xintong operation and inspection class combined with the demand for small current connection fault diagnosis, based on the first half-wave grounding line selection principle, using wireless communication technology, data acquisition technology, computer technology, the development and application of the distribution network grounding fault location device.

2 Innovation Points

The device is innovative in terms of reliability, availability, advancement and maintainability: maintenance-free. The internal use of large-capacity, long-life disposable lithium batteries, with CT power extraction, power extraction current to the supercapacitor charging, supercapacitor to the RF wireless communication module power supply; fault detection, load collection function integration. When a line fault occurs, it detects the type of grounding and short-circuit faults to achieve fault location. During normal operation of the line, load and voltage information is uploaded at regular intervals; Ground fault detection with direction. On the basis of collecting line current and capacitance current, it collects relative ground voltage, increases the criterion of voltage and direction, eliminates the false action caused by excitation inrush current, and greatly improves the correct rate of grounding detection; two-way wireless communication. With local wireless frequency division, frequency hopping network and remote GPRS ‘four remote’ two-way interactive communication dual maintenance function; integrated multi-technology fault indicator. Unconventional technical means to solve a series of problems such as machine power consumption, communication energy, self-power supply, fault detection, fault recording, online monitoring, high current impact, high and low temperature, protection level, lightning surge, EMC, volume, weight and so on.

3 Achieve benefits

Economic benefits. After the implementation of the project, each line trip or grounding can reduce the accident point in a wide range, reduce manual patrol 2 man-days, each man-day 200 yuan, 2 × 200 = 400 yuan, reduce vehicle costs 100 yuan, a total of 500 yuan, according to the 128 flat line road grounding and tripping 58 times in the whole year of 2014, the annual savings of 29,000 yuan; change the traditional fault handling mode, reduce the fault processing time, effectively controlling the scope and time of the fault. The average outage time within the application area of the pilot project construction is reduced from 20.84 hours to 6.85 hours, and the annual power supply is increased by 313,568,000 kWh, which can directly generate economic benefits of 171,500 yuan according to the average price of electricity of 0.5471 yuan/kWh. Social benefits. After the implementation of this project, significant economic benefits have been achieved in addition to effectively improving power supply reliability, and the project has been awarded the First Prize of Science and Technology by Weinan Power Supply Company.

4 Outlook

The distribution network line ground fault location device has been fully applied in State Grid Pucheng County Power Supply Company, and 19 sets of related devices have been deployed in Pucheng County power grid, providing a good basis for the operation of Pucheng power grid line equipment. As a useful attempt of 10 kV distribution network line fault diagnosis, the distribution network ground fault location device has explored the principle of fault routing, communication channels, power solutions, etc., which provides a theoretical and practical basis for further improvement of the fault indication device, and the continuous improvement in the field of fault diagnosis and localisation is an important supplement to realise the high-reliability and low-cost of distribution automation at the level of the agricultural network. The development prospect is huge.

Read more:  https://www.hemeielectricpower.com/