TEPCOs Experience of Stability Problems and Development of Wide Area Special Protection Scheme without Telecommunication
This paper describes Tokyo Electric Power Company (TEPCO) s experience about transient or dynamic instability problems which were caused by great amount of generation loss accompanied with two major earthquakes, and new predictive out of step prevention relay (Special Protection Scheme) that TEPCO and Mitsubishi Electric Corporation(MELCO) developed and applied recently.On Jul.16th, 2007, a major earthquake of magnitude 6.8 hit Niigata region where world largest nuclear power station Kashiwazaki Kariwa is located.Due to this earthquake TEPCO lost all 8GW Kashiwazaki Kariwa nuclear power plants.Since TEPCO retained responsibility to satisfy all demand even after the massive loss of generation, TEPCO had to fully exploit 11GW of pumped storage hydro power, which forced TEPCO to pump up water using substantial electricity at midnight.On Mar.11th, 2011, TEPCO experienced historically large scale outage and generation loss caused by The Great East Japan Earthquake of magnitude 9.0 and accompanied tsunami that wiped out vast area of eastern Japanese coast.Since the loss of generation reached 15GW, TEPCO could not satisfy the demand and had no choice but to perform planned outage right after the disaster.TEPCO ceased the planned outage in several weeks but was still short in generation, which meant heavy dependence on pumped storage hydro and heavy load at midnight for pumping up water.In overall TEPCOs power system, thermal and nuclear generation is predominant in the eastern area while majority of pumped storage hydro is located in the western area.Therefore,the power flow from the east area to the west grows significantly at midnight depending on the amount of pumping, which causes transient instability problem.According to our dynamic simulation study, a severe fault such as 3 phase fault or loss of both double circuit lines in the condition of heavy pumping at midnight could cause pump decelerated or generator accelerated out of step condition which might result in large scale outage.Through this study, we found various mode of out of step phenomena, 1st wave out of step, 2nd wave out of step, Nth (over 3rd) wave out of step and poor damping phenomenon.TEPCO managed to find the way to prevent these out of step phenomena by using old and almost abandoned out of step prevention relay system, but this experience motivated as to develop and apply new out of step prevention relays.Prior to developing the new out of step prevention relay, we set the goal as follows.Predict out of step phenomena and shed some pumped storage hydro machines before out of step to keep the entire system stable.Handle all out of step phenomena, 1st wave out of step, 2nd wave out of step, Nth wave out of step and poor damping phenomenon.Do not require complicated setting that varies by power system condition.Do not require telecommunication channel considering cost.To achieve the goal, TEPCO and MELCO launched the collaborative research based on dynamic simulation study.The research shows that the combination of following methods achieved good result.P-curve estimation method On-line modeling method Angle wave form peak-bottom detection method TEPCO has started to apply this new type SPS and will complete installation to all pumped storage hydro power plants in several years.The results have shown that these new SPSs are effective to prevent all types of out of step phenomena and the reliability in the condition of heavy pump load at midnight meets TEPCOs criteria.
T.Yasuda Y.Suzuki Y.Ichikawa H.Oshida Y.Kowada H.Nishino
Tokyo Electric Power Company, Tokyo, Japan Mitsubishi Electric Corporation, Kobe, Japan
国际会议
南京
英文
306-313
2015-09-21（万方平台首次上网日期，不代表论文的发表时间）