The uncertainty in the conventional power sector is introduced mainly due to volatile nature of the consumers towards their power consumption and intermittency in the penetrated renewable energy resources. Previously load volatility was the only challenge in front of the power engineers and that has been easily sorted either by ramping quality of the thermal generators or by performing load curtailment at the load side. Addressing variability and uncertainty of renewable generation necessitates additional operational flexibility from various resources. It is estimated that by 2022, Indian grid with 175 GW of RE will requiring ramping rate to the tune of 32 GW/Hr and will be a challenge to achieve considering present regulatory system and system approach until drastic steps in forward direction are adopted. Thus the modern power sector needs solutions which can make it adaptive against any dynamic/sudden changes or in other words which can make it flexible.
Improving flexibility of unit over the designed flexible operation, requires either integration of advance control solution or mechanical modification of the system depending upon the quantum of flexibility required. This chapter describes innovative control solution of Condensate Throttling System(CTS) integration in existing DCS along with unit control module in U#6 of Dadri to improve unit primary frequency response (PFR) and ramp rate.
DEMONSTRATION PROJECT
NETRA has implemented this project of integrating CTS solution and Unit control module in existing DCS of Dadri U#6 with following key steps.
- Assessment of Unit capacity for providing PFR and Ramp rate
- Unit assessment for anticipated benefit with retrofitting flexible control
- Condensate Throttling Testing to determine margin and response
- Boilers firing response testing to assess present operating condition
- Speed & size of steam storage assessment to determine present margin for PFC
- Preparation of design document
- Implementation at site and testing
The integration philosophy was to have this solution on operator wish with bump-less. More than 400 operating parameter/status were mapped for processing and providing required control to implement the solution over MODBUS protocol. Hotwell level alarms/switch values were reworked as per the requirement and The project was completed in July-2017 with significant improvement in unit PFR and ramp rate.