The Research On Microprocessor-Based Relays For Medium And Small Generators

It is considerred that medium and small hydropower is a kind of persistent energy source which is drawn a lot of attention in China and even in whole world. Medium and small hydropower can supple electricity power for people in alient area and can make the electrical network more stable. It can also advance region economy and heighten the level of people life. Nevertheless, the research mainly focus on large capacity generators , the research of relay for medium and small capacity generators has been drawn little attention, which brings many projects problems. On the basis of looking back evolvement history and actuality of generator protection, this paper expounds the research work on medium and small generators relay which can be adapted to varying application occasions and high cost performance for generators under 100MW.The medium and small generator relay has technical and economic features. On the basis of analysing design principles and function requirements, an ensemble project design is proposed, and especially the relay has two independent parts. The relay has high reliability because the rational fuction configuration redundance some parts of redundance. This paper detailedly illustrated of all fuctions of the relay and lists the logic chart of every fuction and introduces the algorithm used in the ralay.Compact structure and high cost performance is needed for the relay of medium and small generators. The can easily be changed for different application use which depends on its hardware and software design. The relay has small bulk, its hardware introduces distributed data processing with multiply CPU, which improves the efficiency. The software system has zonal programme design and modularization, which reduces the software maintenance cost.The relay needs to gather direct voltage and direct current, and switch circuit is needed for ping-pang type grouding fault protection for generator rator. According to demand of generator protection, the design scheme for measuring direct voltage and current circuit is proposed, and three schemes for designing ping-pang circuit are also raised, this paper compares the schemes and select one of them as the switch circuit.General protection equipment for medium and small generator has been verified by static simulation experiment and dynamic simulation experiment, and the relay has been used practically. All results manifest that capability of equipment has come up to prospective destinationand the relay meets the technical and economic need.