Seismic Qualification - Circuit Breaker 550 kV Type HPL550/31B2 ABB HV Switchgear AB.

A qualification test was performed according to the ENDESA regulation ETG 1.015 for 0.5g horizontal ground acceleration. A simultaneous time history test in both horizontal axes fulfilling the required response spectrum with damping ratio of 25 % was performed. The damping ratio of 25 % was measured in various frequency search tests.The circuit breaker passed the type test successfully at 0.5g ground acceleration with simultaneous reaction forces from operation of the circuit breaker at a closed and open operation during the earthquake event. There was no damage to the circuit breaker during these test. No significant stresses arised due to the circuit breaker operation. The auxiliary circuit of the operating mechanism type BLG 10002 was energized during the test and no maloperation occured. The gas tightness of the circuit breaker was before, after and during the tests well below leak rate 1 % per year. The mechanical characteristics of the circuit breaker did not show any changes during the tests