Abstract:
Electrical and mechanical operation & Control cost for small hydropower (SHP) contribute to a major portion of capital and annual costs. Conventional methods of control, if applied to control SHP, it becomes totally uneconomical. Most of the SHP sites are in remote areas where manpower is unskilled and has little or no knowledge of operation and control. All these factors contribute to increased outage and frequent shutdown of plants. So operation of a SHP should be as simple as possible involving minimum involvement of manpower. For micro hydro range, using a shunt load governor, which makes load constant hence reducing the control of generator-turbine speed, gates and valves etc., can solve this problem. But this method is uneconomical in large SHPs. Large dump loads are required for it, which is not technically feasible. So digital methods of control and monitoring should be applied to reduce the cost.
Modern microprocessor based programmable Logic controller (PLC) can solve these problems & capable of performing a wide variety of control functions, from discrete logic to closed loop controls. Moreover, its ready availability in the market at reasonable rates has made it an attractive device for use in SHP. The use of PLC based integrated control and protection system in SHP will result in reduced initial cost, less maintenance cost and more efficient operation.
In the present thesis work KEYENCE KV-300 PLC has been used to achieve certain control functions for a hydro-turbine generator demonstration unit in the laboratory of Alternate Hydro Energy Centre as the test system. Programs for various control functions of SHP like automatic unit starting sequence, emergency & fault shutdown, load control, speed control of turbine have been developed in ladder builder for KV version 1.5 software and experimented with demonstration unit successfully. Two Integrated program, by including all above mentioned control programs has been also developed and tested with demonstration unit for the whole control & automation system for a SHP station.
