Tawa Hydro Electric Genration Power Plant
Net head of 21 meters (MWL) to 7.0 meters (at MDDL) is available at the foot of Tawa reservoir, when water is released either for irrigation or spilled to the river. This hydraulic potential is utilised for power generation at Tawa power house.
The reservoir water is passed through the approach channel to intake structure.
- Thrash rack prevents the entry of unwanted material into the water conductor system.
- Stop log gates maintain intake gates during high reservoir level.
- Automatic intake gates provide additional safety to the unit. They are designed to close in case of emergency.
- From intake structure the water directly enters the scroll case of the turbine units.
- Turbine speed is synchronised with the grid frequency through Hydro Electric governer, which operates the servomoter. Turbine acts as a prime mover to drive 11 KV, 28 pole synchronous generator . Power generated at the generator terminals varies from 1. 5 MV to 8.1 MV depending on the availability of net head and water discharge.
Power generated at the generator terminals is transmitted to the switch yard, where it is stepped to 33 KV by means of 9 MVA outdoor transformers. Excitation current is supplied to generators via resin cast Excitation transformers and static Excitation equipment. Two parallel transmission lines evacuate the power to the MPEB grid at Pathrota. Exhaustive protection system is provided on 110 V DC with battery backup. For any fault in the unit operations, alarm systems are automatically activated and the machines will trip depend on the severity of the fault. Both the units are fully automated and operations can be started / stopped from any stage through single button command either from MMI ( Man Machine Interface) or Auto Sequencer.
Instrumentation and Control Systems
Tawa unit is provided with centralised automatic instrumentation and control system.
The operations of the unit is performed from the Operator console of the Supervisory Control and Data Acquisition (SCADA) system provided in the control room.
The instrumentation and control system provides control over the entire power plan that includes starting, smooth running and stopping from the central control room.
Transducers / transmitters and other instruments are provided on various equipments of power house for generating analog and digital signals to meet the requirements of PLC system