考虑运行安全裕度的长时储能容量优化配置方法及其应用研究

Capacity Optimization and Application Research of Long-Duration Energy Storage Considering Operational Safety Margins

摘要: 针对高比例新能源系统中短时储能调节时域不足，以及传统容量规划模型对储能安全运行边界和寿命健康影响考虑不充分的问题，提出一种考虑运行安全裕度的长时储能容量优化配置方法。首先，构建包含新能源、上级电网、负荷和长时储能的源网荷储协同运行模型；在给定储能持续时长条件下优化储能额定功率，并据此确定额定能量，以年化投资成本、购电成本、弃电成本、失负荷成本、需量成本、充放电运维成本和等效寿命衰减成本之和最小为目标。其次，将安全裕度界定为储能在常规调度之外为避免过充过放、过度深循环和突发功率缺额而保留的可运行边界，包括SOC安全区间、最大放电深度、日等效循环次数和最低安全SOC之外的应急备用电量，并将其统一转化为线性约束，形成兼顾经济性、供电可靠性、运行安全性和资产健康的混合整数线性规划模型。最后，基于四季典型日按权重扩展形成的8760 h等效时序，设置无储能、4 h常规储能、8 h长时储能和8 h安全约束长时储能4种方案进行对比，并补充持续时长、功率上限、投资成本、失负荷价值、购电价格和安全裕度水平的敏感性分析。算例结果表明：8 h长时储能可在较低功率配置下消除失负荷，较4 h常规储能降低年总成本4.62%；引入安全裕度后，最优配置由74.52 MW/596.20 MWh调整为78.19 MW/625.55 MWh，年总成本增加2.11%，最大放电深度由89.51%降至68.47%，年等效循环次数下降13.43%。敏感性分析表明，在本文参数条件下8 h方案综合成本最低，且该结论在一定的投资成本、失负荷价值和购电价格扰动范围内保持稳定。所提方法可为长时储能工程容量论证、安全运行边界确定和安全–经济分级决策提供参考。

Abstract: To address the insufficient regulation duration of short-term energy storage in power systems with a high penetration of renewable energy, as well as the insufficient consideration of safe operating boundaries and asset-health impacts in conventional planning models, a capacity optimization method for long-duration energy storage considering operational safety margins is proposed. A source-grid-load-storage coordinated operation model is first established. Under a given storage duration, the rated power of energy storage is optimized and the rated energy is determined accordingly. The objective is to minimize the sum of annualized investment cost, electricity purchase cost, renewable curtailment cost, loss-of-load cost, demand charge, variable operation cost, and equivalent life-degradation cost. Then, the operational safety margin is defined as the feasible operating boundary retained beyond normal dispatch to avoid overcharge/overdischarge, excessive deep cycling, and emergency power shortage. The safe SOC range, maximum depth of discharge, daily equivalent-cycle limit, and emergency reserve above the minimum safe SOC are formulated as linear constraints, resulting in a mixed-integer linear programming model that coordinates economy, reliability, operational safety, and asset health. Based on an 8760 h equivalent time series expanded from four weighted representative seasonal days, four cases, namely no storage, 4 h conventional storage, 8 h long-duration storage, and 8 h safety-constrained long-duration storage, are compared. Sensitivity analyses on storage duration, power limit, investment cost, loss-of-load value, electricity price, and safety-margin level are also added. The results show that the 8 h system eliminates load loss with a lower rated power and reduces the annual total cost by 4.62% compared with the 4 h conventional system. After introducing safety margins, the optimal capacity changes from 74.52 MW/596.20 MWh to 78.19 MW/625.55 MWh, while the annual cost increases by 2.11%; the maximum depth of discharge decreases from 89.51% to 68.47%, and the annual equivalent cycles decreases by 13.43%. The sensitivity results indicate that the 8 h configuration achieves the lowest comprehensive cost under the parameters used in this paper and remains robust within a certain range of key economic parameters. The proposed method can provide a reference for engineering capacity demonstration, safe operating-boundary determination, and graded safety-economic decision-making of long-duration energy storage.