Achieving unity power factor at floating grid conditions in a cement plant in India - Case Study

Most cement plants in India and around the world face a unique problem in regards with power factor. In industries where their local generation with their Captive Power Plant (CPP) and Waste Heat Recovery System (WHRS) is equal to or greater than the plant's total utilization, the load import from the Grid is brought down close to zero. This is done to reduce the power cost because the Grid power is comparatively expensive. Though the Grid power is not required, the connection to the Grid is mandatory for the system in floating mode to ensure the stability of the system, to avoid black-outs in the event of CPP failures/trips and to tackle unplanned/sudden variations in the load. Such a setup makes it extremely complex to maintain power factor at the Grid incomer. For more than a decade, it was assumed that no solution exists to this problem where CPPs are connected and power drawn from the Grid is close zero. In India, a state like Chhattisgarh, where Grid billing is in kVAh and on TOD
¹
1TOD- Time of Day billing system. It refers to the practice of setting different price for a of unit energy at different times of the day. The general classification is On-Peak, Off-Peak and Normal hours. basis, power factor plays a major role in Grid cost optimization. This paper contains a discussion on the problem, the solution and a case study of achieving unity power factor at floating grid conditions in a cement plant in India.