Development Of Testing Platform For Feeder Fault Indicator Of Distribution Network

Feeder fault indicator in distribution network (FI) is installed in branch point and inlet line from user, etc. When short-circuit fault or single-phase ground fault occurs, point of failure can be located quickly by maintenance staff based on a fault alarm indication of FI. It provides a favorable security for troubleshooting and restoring power as soon as possible, and thus improves the reliability of power supply. However, without any standardization of FI, the products from different manufacturers vary greatly in their function due to various technical conditions, which hampers application of FI in troubleshooting. In 2010, the State Grid Corporation issued and implemented Q/GDW436-2010 "Technical Specification of Fault Indicator in Distribution Network". It provides a technical basis of procurement and acceptance for power enterprises.At present, in FI testing, small current is commonly used to simulate faults. However, this simulated fault differs from a real one, and standardized FI is still not well applied. This paper develops a testing platform for feeder fault indicator of distribution network. This platform uses high voltage and high current to stimulate fault, based on Q/GDW436-2010 "Technical Specification of Fault Indicator in Distribution Network", to detect fault alarm of short circuit, avoid non-fault fluctuation, and detect electrical properties, etc. Meanwhile, the platform also provides three-phase line simulation demo for the study of distribution automation based upon FI. The testing platform consists of 3 units, information processing unit, fault detection unit and voltage and current output unit. Information processing unit is a high-performance PC with detection software. Fault detection unit is a self-developed device integrating measurement and control, including communication control section and alternating quantity I/O section. The former has PLC as its control core and the later is used to assist control, which inputs and outputs voltage and current waveform signal. Voltage and current output unit is made of circuits and devices which output high voltage and high current.PLC software of the device uses a structured, modular programming. The frame of the software is well designed through stepwise refinement and improves the reliability. The device is endowed with user-friendly interface with a tough screen. Development method based the abandonment prototype of V-model is used for detection software in PC. The software is divided into multiple modules based upon functional types, which are coded, packaged and tested separately, to ensure the quality and efficiency of software development.The application of testing platform is further described with ZY-F10 and KLD2-A as the fault indicator for testing. This article introduces test procedures of some test items of FI and three-phase line simulation demo. Practical application shows that the platform is stable and reliable operation, to achieve the desired functionality.