阀内冷膨胀罐氮气循环利用系统的设计及应用

阀冷却系统作为换流站内核心设备，其安全稳定运行直接关系到直流系统的运行状况。为解决阀冷却系统膨胀罐稳压氮气消耗过大无法循环利用的问题，通过氮气稳压系统理论模型计算得出膨胀罐温度-压力变化曲线，设计了一套阀内冷膨胀罐氮气循环利用系统及对应的控制策略，经过现场试验论证，设计的循环利用系统能够有效解决阀冷却系统氮气消耗问题，实现阀冷却系统的持续稳压，保障直流系统的安全稳定运行。

Design and application of a nitrogen recirculation system for the cooling expansion tank within the valve hall

As a critical component within converter stations,the valve cooling system is integral to the safe and stable operation of high-voltage direct current (HVDC) systems.Addressing the issue of excessive nitrogen consumption in the cooling expansion tank,which could not be efficiently recycled,this paper calculates the temperature-pressure variation curve for the expansion tank through a theoretical model of the nitrogen regulation system.Subsequently,a nitrogen recirculation system and the corresponding control strategies are designed for the cooling expansion tank inside the valve hall.Through field testing,it has been demonstrated that the designed recirculation system can effectively mitigate the issue of nitrogen consumption in the valve cooling system.This leads to sustained pressure stabilization within the valve cooling system,ensuring the safety and stable operation of the HVDC system.