利用含电解槽的微电网将可再生能源转化为氢能进行存储,是提高可再生能源消纳率的有效途径。为减缓可再生能源出力的波动性和随机性对微电网经济性和稳定性的影响,需要合理分配微电网中电解槽、电化学储能、燃料电池等关键设备的运行功率。电解槽运行时,由于隔膜无法完全隔绝氢气和氧气,所产生的气体不可避免地出现交叉,尤其在低负载运行时,氢氧交叉比例显著上升。当氢氧交叉比例超过安全极限时,可能引发爆炸等严重安全问题。因此,微电网功率分配中需要限制电解槽的运行功率下限。现有研究多采用恒定的电解槽功率下限。然而,由于电解槽的氢氧交叉比例随功率变化,且不同时段微电网运行工况差异显著,恒定电解槽功率下限的调度方法存在无法有效避免氢氧交叉比例越限和限制电解槽调节能力等潜在问题。此外,微电网中常配置碱性电解槽和质子交换膜电解槽,两种电解槽氢氧交叉比例随功率变化的特性存在显著差异,分别设定其功率下限将进一步增加调度复杂性。为解决上述问题,分析碱性和质子交换膜电解槽的运行特性,建立电解槽动态安全约束,并提出了考虑混合电解槽动态安全约束的光–氢–储微电网调度方法。仿真结果表明,与传统调度方法相比,所提方法能够有效保障电解槽安全,为含氢储能微电网优化调度提供了新的思路。

Equipping microgrids with electrolysers which convert renewable energy sources (RESs) into hydrogen for storage is anefficient approach to enhancing RES consumptions. This requires rational power allocation among controllable devices,such aselectrolysers,electrochemical energy storage systems and fuel cells,within microgrids so as to mitigate the impacts of RES fluctuations onsystem economics and stability as well as equipment safety. Since the membrane of electrolysers cannot completely separate the productionof hydrogen and oxygen,the proportion of gas crossover will accumulate,especially during low-load operation,and might eventuallyexceed the maximum allowable limit and cause explosion. Therefore,the lower operating limits of electrolysers must be taken into accountto allocate power between electrolysers and other components within microgrids. Constant lower power limits are usually specified forelectrolysers to ensure their safe operation. However,the use of constant lower limits for electrolysers has certain limitations since theoperating conditions of microgrids together with electrolysers dynamically change over time. A constant lower limit would be tooconservative to exploit the ability of an electrolyser to absorb RESs,and sometimes may fail to prevent excessive crossover when anelectrolyser operates at low loads for long time. In addition,microgrids typically incorporate both alkaline electrolysers (AELs) andproton exchange membrane (PEM) electrolysers,which exhibit distinct gas crossover characteristics. This further increases the complexity of microgrid scheduling due to the fact that lower power limits must be set for each electrolyser type separately. To addressthese challenges,this paper first establishes dynamic safety constraints for AEL and PEM electrolysers based on a comprehensive analysisof their operational characteristics. Then,a microgrid scheduling method is proposed to maximise the overall benefits from hydrogenproduction and electricity price arbitrage by optimising power allocation to a photovoltaic plant,battery energy storage system,fuel cell,AEL and PEM electrolysers subject to the safety constraints. Simulation results demonstrate that,compared with traditional schedulingmethods that adopt constant lower limits for electrolysers,the proposed approach effectively ensures dynamic safety of electrolysers interms of gas crossover,providing a novel framework for the scheduling of hydrogen-based microgrids.