Analysis of GHE system's DC emergency oil pump reform solution at Fuqing nuclear power plant

Analyze two issues about GHE system's DC emergency oil pump at Fuqing Nuclear Power Plant Units 1 and 2 that the drive motor excitation current far more than the rated value, and the change form separated excitation to shunt excitation. Put forward that: (1) the excitation current far more than the rated value will cause decline in the motor speed, the pump flow and head, and the motor overheating; (2) change form separated excitation to shunt excitation under field conditions make no essential difference. For the two issues raise two reform solution that change the excitation method from shunt excitation back to separated excitation, or replace the separated excitation motor, with cumulative compound excitation motor. Analysis and compare the two solutions, proposed that the last one is more feasible in terms of practical experience and cost and so on. The last solution is proofed practical according to the test result after reform. (authors)