China's 220 kV circuit breaker forced outage rate is declining year by year

On June 28, Chen Lijuan, deputy director of the Reliability Management Center of the China Electricity Council (the State Electricity Regulatory Commission's Power Reliability Management Center) pointed out: “In the past decade, the main reason for the long unplanned downtime was due to poor product quality. The equipment manufacturing department should pay great attention."

According to Chen Lijuan, the level of reliability has increased year by year. As of 2011, there were 397 power supply companies (including 65 ultra-high voltage power transmission enterprises) and 417 power generation enterprises nationwide, and they reported 220 kV to the power reliability management center. Reliability statistics data for 13 types of transmission and transformation facilities with voltage levels above.

Relevant data show that over the past decade, the number of circuit breakers with voltage ratings of 220 kV and above has increased rapidly, the reliability level has increased year by year, and the rate of forced outages has dropped significantly. The number of unplanned outages exceeding 300 hours has decreased year by year. The outage time showed a trend of shortening, in particular, the 2011 500 kV circuit breaker was only one time; the availability coefficient of domestic and imported circuit breakers showed an upward trend year after year, and maintained at a relatively high level in recent years.

According to statistics, the highest value has been reached in the past decade in 2011; the rate of forced outage of domestic circuit breakers has been declining year by year, and it has reached the lowest value in 10 years in 2011, and the forced outage rate of imported circuit breakers has declined. , And in 2011 reached the lowest value in 10 years.

According to a comparative analysis, in the past decade, although the forced outage rate of domestically produced 220 kV circuit breakers showed a downward trend, the forced outage rate of imported circuit breakers was significantly lower than that of domestic circuit breakers.

From the 2011 data, it can be seen that the 220 kV circuit breaker was caused by an unplanned outage. The breakdown by location is mainly the operating mechanism, the arc extinguishing section, and the porcelain sleeve. The number of unplanned outages caused by the three aspects is 26, 4, and 3 respectively. Times; the percentage of the total non-planned outages reached 58.451%, 14.128%, and 7.924%, respectively. The main part of the unplanned outage of the 330 kV circuit breaker is the single-phase reclosing device and the operating mechanism, and the number of times is 1, 11 times.

The main part of the non-planned outage of the 500 kV circuit breaker is the auxiliary circuit of the operating mechanism and operating mechanism, and the number of times is 11, 2 times respectively.

“The main reason for the long-term unplanned outage of circuit breakers is due to the malfunction of the operating mechanism. In particular, the proportion of 220 kV circuit breakers that are out of service due to the failure of the operating mechanism accounts for the proportion of the total non-planned outage time, which remains high.” Summarized.

From the non-planned outage statistics of circuit breakers in 2011, it can also be seen that poor product quality, aging equipment, and climate factors are also the main reasons.