网侧分层接入500kV/1000kV交流电网的特高压直流系统控制保护方案

Control and Protection System Scheme on UHVDC With Hierarchical Connection to 500 kV/1000 kV AC Systems

受端分层接入500 kV/1000 kV不同电压等级交流电网的特高压直流接线方式在世界上属于首创,其控制保护没有可借鉴的经验。系统研究了该种接线方式的直流控制保护系统方案。分析了特高压直流受端网侧分层接入500 kV/1000 kV交流系统接线方式对直流控制保护的特殊要求,提出了网侧分层接入特高压直流控制保护系统的分层结构和功能配置方案,分析了功率正送和功率反送运行方式下直流控制策略的差异,提出了适用于正、反送运行方式的直流控制策略。对分层接入控制系统的关键功能,如阀组间电压平衡控制、分接头控制、无功控制、功率转移及分配等功能进行了分析和研究,提出了各功能的原理及实现方法。提出了受端分层接入直流工程直流保护的分区和功能配置,以及与常规特高压直流工程的差异。最后对直流场测点配置进行了分析。研究成果已应用于在建的分层接入特高压直流工程。

UHVDC project with hierarchical connection to 500 kV/1000 kV AC systems in receiving end is creative worldwide. There is no existing experience for this kind of DC control and protection. This paper studied control and protection scheme systematically. Special requirement on DC control and protection for UHVDC project with hierarchical connection to 500 kV/1000 kV AC systems in receiving end was analyzed. Hierarchical structure and function configuration of DC control and protection was presented. DC control strategy difference between normal power and reverse power operations was analyzed. DC control strategy adaptable to both normal and reverse operation was put forward. Key functions such as voltage balance between two 12-pulse converters, tap changer control, reactive power control, power transfer and distribution were studied. Its principle and implementation was presented. DC protection area allocation and function configuration for hierarchical connection DC system was promoted and variation with previous UHVDC project was compared. Measurement configuration of DC yard was analyzed. Study achievement was put into use in such kind of UHVDC project under construction.