计及能源转换负荷影响的气电耦合系统连锁故障评估

Evaluation of cascading failures in an integrated gas and power system considering effects of energy conversion load

气电耦合系统中电转气负荷与气转电负荷为故障在电网与气网间的传播提供了通道,将电转气负荷与气转电负荷统称为能源转换负荷,其在电、气负荷中的占比与在阻断控制过程中的切除优先度可能对耦合系统连锁故障的传播特性带来无法忽视的影响。为此,提出了一种计及能源转换负荷影响的气电耦合系统连锁故障评估方法。首先,提出能源转换负荷占比与切除优先度模型,分析不同占比与切除优先度下故障在电、气网间连锁传播的机理与特性。然后,分别建立基于能源转换负荷占比与切除优先度的电力系统优化调度模型与天然气系统优化调度模型,两者交替迭代模拟连锁故障演化过程。基于此,提出表征拓扑完整性与物理运行特性的指标以定量评估连锁故障风险,从而构建气电耦合系统连锁故障评估模型。最后,利用IEEE RTS 24节点系统与29节点天然气系统构造气电耦合测试系统,通过对比不同场景,验证了所提方法可有效揭示能源转换负荷对连锁故障的影响。

Power to gas and gas to power loads in the integrated gas and power system can provide a channel for fault propagation between the power grid and the natural gas network.They are defined as conversion load.Their different proportion in power load and natural gas load and shedding priority in blocking control may have different impacts on the propagation characteristics of cascading failures.Therefore an evaluation method of cascading failures considering energy conversion load effects is proposed.First,the models of the proportion and shedding priority of energy conversion load are proposed to analyze the cascading propagation mechanisms and characteristics of the failures in the system at different proportions and shedding priority.Then,the optimal dispatching models of the power and the natural gas systems based on the proportion and shedding priority of energy conversion load are established respectively.The two models are iterated alternately to simulate cascading failures.From this,the indicators in topology and physics are proposed for quantitative evaluation of cascading failure risk.Thus,a cascading failure evaluation model of an integrated gas and power system is built.Finally,the integrated gas and power test system composed of an IEEE RTS 24-bus system and a 29-bus gas system is employed to validate effectiveness of the proposed method in revealing cascading effect by comparing different scenarios.