清原抽水蓄能电站直流系统级差配合探讨

Discussion on stage difference coordination of DC system in qingyuan pumped storage power station

摘要

抽水蓄能电站电源系统中，直流电源作为控制电源、继电保护及装置电源以及部分重要电机的动力电源，是整个机组安全稳定运行的重要保障。随着智能电网技术的不断进步，电站内部的保护与控制负荷日益增多，这进一步提升了对自动化与智能化设备的需求。在直流系统中，对保护电器的过载保护和短路保护提出了更高的标准，要求这些电器在操作中既不能误动也不能拒动，特别是要避免越级动作的情况发生。一旦发生此类情况，可能会引起电力元件损坏，进而导致事故范围扩大，甚至可能引发大面积停电。国家电网针对直流电源的可靠性问题，已启动了一系列研究工作，其中一项关键任务是优化直流系统中空气开关的短路级差配合。直流空气开关级差配合是评判直流电源系统配置合理与运行安全的主要指标之一。级差配合计算验证了直流电源上下级空气开关是否符合设计规程，是否可将故障时的切除范围限制在最小从而最大程度保证直流电源的供电可靠性。本文详细阐释了极差配合计算的基本原理与主要方法，结合清原抽水蓄能电站直流系统级差配合计算书，提出了优化直流电源系统配置、消除直流系统安装隐患、加强直流系统运行维护的方法与建议。

Abstract

In the power system of pumped storage power station, DC power supply, as the control power supply, relay protection and device power supply and the power supply of some important motors, is an important guarantee for the safe and stable operation of the whole unit. With the continuous advancement of smart grid technology, the protection and control loads within power stations are increasing, which further enhances the demand for automated and intelligent equipment. In DC systems, higher standards are set for overload protection and short-circuit protection of protective devices, requiring these devices to neither false operate nor refuse to operate, especially to avoid over-stepping actions. Once such a situation occurs, it may cause damage to power components, leading to an expansion of the accident scope, and even potentially triggering large-scale blackouts. The State Grid Corporation has initiated a series of research efforts regarding the reliability of DC power supplies, with a key task being the optimization of short-circuit level coordination for air switches in DC systems. The differential coordination of DC air switch is one of the main indicators to judge the reasonable configuration and safe operation of DC power supply system. The differential coordination calculation verifies whether the upper and lower air switches of DC power supply comply with the design specifications, and whether the fault removing range can be limited to the minimum to ensure the reliability of DC power supply to the greatest extent. This paper explains the basic principle and main method of range matching calculation in detail. Combined with the DC system level difference matching calculation of Qingyuan Pumped Storage Power Station, the paper puts forward the method and suggestions to optimize the DC power system configuration, eliminate the hidden dangers, and strengthen the operation and maintenance.

关键词

直流系统 / 级差配合计算 / 选型建议

Key words

DC system / stage difference coordination / model selection advice

Author summay

郭晓原(1986—), 女, 高级工程师, 硕士, 主要从事电气二次设计。E-mail: [e-mail]