智能配电网负荷转移能力评估指标体系研究

During overload running, equipment overhauling or fault occuring ,it will lead to much load losses or wide spread break out easily if we fail to transfer load in time. So, higher load transfer ability is an effective method to solving these problems under these special operation modes for smart distribution grid(SDG).This project focuses on load transfer ability of SDG under equipment maintenace and fault condition,and will develop new multi-factor assessment model with hierarchical structures of load transfer ability of SDG. In this assessment index system ,a scheme of assessment index system is redisigned and assessment indexex are redefined. This model can reflect some main features of SDG as flexibility, two-way interactivity etc . This project also focuses on some influence factors to simulation result include power supply random variation characteristics of these distributed power sources such as smaller wind power station and PV station connected with SDG. Some other influence factors are also analyzed such as control strategy of energy storage system such as storage batteries and coordinated schedule policy of SDG，user demand ,etc. The simulation model of assessment index and calculation method of weighting coefficients of assessment inex deeply influenced by uncertain factors are key areas in this project. The optimum mathematic model for minimum power outage time, loss power of the load and network loss rate is designed, and the number of segments is automatically computed due to the inherent heuristic searching. Finally some examples are given to validate these mathematical models . The assessment system and methodologies are also expected to find applications in other SDG related research and should be valuable contribution to futher research in improvement of power support capacity and investment benefit.

电网在超负荷运行、设备检修或发生故障时,应能及时高效地完成负荷转移，保持持续供电能力。本项目针对智能配电网在检修或故障等N-1状态下的负荷转移能力，重新定义评估指标，设计评估指标体系层次结构；考虑分散并网的小型风电站、太阳能光伏电站等分布式电源的随机供电特性，以及蓄电池储能装置的控制策略，智能配电网协调调度策略和用户需求等影响因素，重新建立反映智能配电网灵活性、双向交互性等主要特征的分层框架结构多因子评估模型；采用层次分析法求解指标权重，重点研究受不确定因素影响较大的评估指标权重求解方法；以最小停电时间、最小失荷量和最小网损率为优化目标，采用启发式搜索方法优化综合评估指标标准值,通过算例验证评估效果。本项目研究成果，可为考虑负荷转移能力的智能配电网评估提供理论支持，对有效利用各种能源、提高电网各区域的供电支持能力和重构有指导意义。

配电网中分布式电源和微电网分散接入、负荷时变特性和类型特征、可控负荷主动调控等，给配电网规划和运行带来诸多重要影响，如何优选故障后负荷转移方案，在保证配电网安全可靠经济前提下尽可能恢复更多失电负荷成为不容回避的问题。建立了分布式电源和微电网出力概率模型、负荷时序和调控优化模型、孤岛划分和重构优化模型、孤岛运行概率模型，提出微电源和微电网间协调控制策略、基于负荷特性和供电要求的负荷消减策略、负荷主动调整控制策略，深入研究了电源出力不确定性、负荷特性和需求响应不确定性、孤岛运行不确定性等因素的影响，重新设计和定义配电主网、孤岛微电网的各层评估指标，分析评估指标标准的制定原则和重点考虑问题，改进了基于模糊层次分析法的指标权重设置方法。可靠性、经济性、供电能力等方面的评估结果表明，过度增大分布式电源和微电网接入容量，有可能造成能源利用率和孤岛微电网源、荷协调性变差。合理设置微电源和微电网容量配比、有计划的孤岛分区、负荷主动调控，有利于借助储能装置的有效调节，充分发挥分布式电源、微电网对故障恢复和孤岛稳定运行的积极作用，全面提升配电网负荷转移能力。项目研究为综合评估不确定性因素对配电网负荷转移能力影响奠定理论基础，为智能配电网规划、协调调度、故障恢复提供科学依据。