浅谈提高电厂高压母线电压合格率的方法

Discussion on Method of Improving the Voltage Pass Rate of High Voltage Bus in Power Plants

实际电压与电网的基准电压偏差过大,不仅会对各类家用和工业的电器设备造成损坏,而且极有可能会危及全网及并网的发电机组正常运行,甚至可能引起电网局部震荡或整体解列、并网发电机跳机。将电力系统的电压维持在合理的偏差范围内运行,一直是电网和发电企业极为重视的问题之一。通过分析华东电网统调电厂AVC系统构架和运行机理,分析影响电厂高压母线合格率的因素,分析某电厂500 kV母线电压合格率较低的原因,提出针对性的解决方案。提高母线电压合格率的主要方法:检查发变组保护采样精度、电压压降;检查调整AVC定值;检查调整AVC控制逻辑;检查远动装置、数据网的正确性;将机组电压变送器由传统式变送器更换为数字式变送器。经治理后,该电厂AVC合格率有明显的上升。

The deviation between the actual voltage and the reference voltage of the power grid is too large,which not only causes damage to various household and industrial electrical equipment,but also potentially endangers the normal operation of the entire grid and grid-connected generating units,and may even cause local oscillation or overall disconnection of the grid,and the grid-connected generator tripping.Maintaining the voltage of the power system within a reasonable deviation range has always been one of the issues that are highly valued by power grids and power generation companies.By ana-lyzing the AVC system architecture and operating mechanism of the power plants under unified dis-patching of East China Grid,analyzing the factors affecting the qualification rate of high voltage bus in power plants,and analyzing the reasons for the low qualification rate of 500 kV bus voltage in a certain power plant,a targeted solution is proposed.The main methods to improve the qualification rate of bus voltage are:checking the sampling accuracy and voltage drop of generator-transformer unit protection;checking and adjusting AVC constant value;checking and adjusting AVC control logic;checking the correctness of remote control device and data network;replacing the traditional voltage transmitter of generating unit with digital voltage transmitter.After treatment,the AVC qualification rate of this power plant has significantly increased.