Rajan Babu Vinayagamoorthy
Electric power supply comprising of both OFF site and ON site power supply systems is designed to facilitate functioning of equipment important to safety during normal operation, anticipated operational occurrences and accident conditions. Reliability of both OFF site and ON site electrical power supply systems is of paramount importance as it feeds the power for Reactor coolant pumps and other auxiliaries during normal operations during normal & accident conditions.
The emergency electric power supply (Class IE) system is generally categorized into three types based on the power requirements of the loads.
1. AC power supply to Auxiliaries, which can tolerate short interruption upto 3 minutes is classified as Class-III AC Emergency power supply.
2. No break AC power supply to auxiliaries derived from class-III buses through rectifier/charger and inverter with a battery backup is called class-II power supply.
3. No break DC power supply to auxiliaries derived from Class-III buses through rectifier/charger with a battery backup is called Class-I power supply.
All Emergency power supply systems are designed to fulfill the safety criteria for Class-IE power supply system such as adequate redundancy by independent division having necessary capability & reliability, physical separation and functional isolation etc.
Variable speed AC drives are provided for the two each PSP & SSP pumps. An AC Pony motor is additionally provided for each of the primary sodium pumps. The electrical heating system for sodium circuits are designed to prevent arcing damage to the pipe and equipment that might be caused by the electrical heaters by adopting ungrounded power supply system. The insulation monitoring devices are provided in sodium circuits. The heaters on the primary sodium and Argon line are triplicated and heaters on the secondary sodium systems are duplicated.
Each section of the 6.6kV switchgear, 415V PCC, MCC, HCCs are provided with Switchgear Interface Panel to facilitate necessary interface/interlock for control, metering, indication, Annunciation and also provides galvanic isolation between electrical equipment and main control room.
The installation of about 500 panels at various buildings are challenging due to layout constraints, complex design, approach issues etc. The presentation focuses on the challenges faced during installation & commissioning of various electrical equipment right from 230 kV Gas Insulated Switchyard. The paper briefly discusses on the up-gradation of heater requirement for preheating of sodium circuits, provision of additional DG sets for extending power supply beyond SBO condition.
Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI)
Department of Atomic Energy,
Kalpakkam 603 102, Tamilnadu, India
OBULI B OBULI B
(PFBR, BHAVINI, DEPARTMENT OF ATOMIC ENERGY, KALPAKKAM, INDIA)