巴西“9.13”远西北电网解列及停电事故分析及启示

Analysis on and Inspiration of the “9.13” Islanding and Outage of Brazilian Remote Northwest Power Grid

2016年9月13日15时50分,±600kV Madeira Ⅰ直流沿线山火造成双极先后故障跳闸,在直流线路故障及再启动过程中,大量潮流反复转移至另一小容量交直流并联输电通道,引起系统振荡等异常现象,造成巴西远西北部两州ACRO电网与巴西国家互联电网解列。ACRO孤网频率升高,电压降低,引起大量切机和切负荷。与巴西电网曾发生的多次大停电相似,此次停电再次表明：虽然近年巴西输电网基础设施投资和建设已显著加大力度,但是,影响巴西电网安全稳定运行的网架结构、运行管理和系统控制等深层次问题并未根本扭转,一是,此次故障与大容量水电厂交/直流、大容量、远距离点对点输电方式密切相关,表明巴西电源结构、电网网架、电网结构规划建设方案仍需优化;二是,由于未能正确看待系统仿真过程中已发现的N-2下系统小概率高风险事件,在系统运行方式安排时未充分考虑,导致事故发生,表明巴西电网运行方式安排具有提升空间;三是,故障发生和处理过程中,遇到了保护、控制、监控、站用电、通讯系统等一系列异常和故障,扩大了事故范围,增加了事故分析判断难度、延迟了故障恢复时间,表明电网运行维护水平可继续提升。“9.13”远西北电网解列和停电事故集中体现了巴西在电网规划、建设和运行、管理等方面的特点,表明巴西电网加强管理、保障电网安全任重道远,也对我国高压直流输电技术装备首次输出海外的巴西美丽山示范工程未来安全稳定运行提出了挑战。

At 13：50pm, September 13th, 2016, pole 2 and pole 1 of ＋600kV Madeira I tripped one by one which was caused by fire along the DC lines. In process of fault and restart of the DC line of ＋600kV Madeira I, power flow had repeatedly transferred to another small-capacity AC/DC parallel transmission channel, system oscillations happened, which resulted in ACRO grid＇s islanding from Brazilian SIN. In ACRO isolated grid, frequency increased, voltage dropped, companying with plenty of generation and load shedding. Similar to other blackouts occurred in the Brazilian power grid, the ＂9.13＂ outage again shows that the critical issues which have been affecting safety and stability of Brazilian power grid, includingnetwork structure, operation management and system control, have not been fundamentally solved until now, even if investment and construction of the Brazilian transmission network infrastructure have been significantly strengthened from the year of 1999. Firstly, the fault was closely related to the AC/DC, high-capacity, long-distance point-to-point transmission mode of large-capacity hydropower plants, indicating that the power supply structure, power network structure and programs of Brazilian power grid＇s planning and construction need to be optimized. Secondly, N-2 event, with both small probability and high-risk, resulting in the outage, had not been fully taken into consideration in arrangement of system operation mode which indicates that there is room for improvement of the operation mode arrangement in Brazilian power grid. Thirdly, a series of abnormalities and faults, being related to protection, control, monitoring, station power supply and communication system, were encountered, which resulted in enlargement of accident area, difficulties of accident analysis and judgment, the delayed fault recovery time, which indicated that the power grid＇s operation and maintenance level need to be improved. ＂9.1Y＇ outage in Brazilian remote northwest power grid shows the characteristics of planning, construction,operation and management of Brazilian power grids. There is still room to be optimized in strengthening management aiming at ensuring safety of the Brazilian power grid. It shows that the 1st oversea ＋800kV Brazilian Belmont project, exporting both Chinese UHVDC technologies and equipments to Brazil, has been facing a serious challenge of both security and stability of operation in Brazil in the future.