Working of Pumped storage hydroelectric power plant :-
It consists of head water pond (reservoir) and tail water pond by constructing a dam at tail race path.
Tail water pond and head water pond connected through penstock.
During peak hours the turbine drives the generator and generates electrical energy.
The excess energy generated by steam and nuclear plants during the offpeak load is utilized to drive the motors in the pumped storage plants
During OFF peak hours the generator operates as a motor. And drives the turbine which now works as centrifugal pump.
Raising the water from tail water pond to head water pond through penstock.
Such plants can be operated only in interconnected system, where other generating plants (such as TPP & NPP) are available during their off load period.
In this case, Francis turbine is used
Advantages of Pumped storage Power Plant;
1. It is saves water by reusing same water again & again. 2. There is less expenditure during pumping of water because water is pumped when surplus power is available i.e. during OFF load period. (Through interconnected system) 3. It can be put into service immediately; hence it is useful to supply power during peak load period. 4. It increases load factor of power plant (generally TPP) 5. It helps in reducing install as well as spinning reserve capacity of TPP as it provides additional power during peak load period.