配电网负载侧互联装置 SNOP 控制策略研究

针对电力系统中新能源发电不断增加,其不均衡性和日益增长的用户负荷多样性对电网产生冲击这一问题,提出了一种基于双变压器的低压母线侧负载并联系统。 利用 SNOP(Soft Normally Open Points,智能软开关)的双向调节能力把配网系统中两个变压器低压用电侧互联,取代传统的联络开关,提高电能质 量和系统的可靠性,在背靠背式 VSC(Voltage Source Converter,电压源换流器)电路基础上添加储能系统作为 SNOP 的拓扑结构,提高了系统的可靠性,在交-直-交转换下保证能量互换的安全可靠。 根据其拓扑结构建立数学模型,研究了双闭环控制结构下的控制策略,并结合储能单元综合考虑其控制策略,保证储能单 元的兼容性。 最后通过 MATLAB 仿真验证双闭环控制策略下的储能型 SNOP 系统理论的正确性和可靠性,试验结果表明,储能型 SNOP 可以很好地对变压器两侧负载进行互联,以此缓解重载侧变压器压力。

Research on SNOP Control Strategy of Load Side Interconnection Device in Distribution Network

Aiming at the impact of the continuous increase of new energy generation in the power system, its imbalance and the increasing diversity of user loads on the power grid, a dual-transformer-based low-voltage bus side load parallel system is proposed. The two-way adjustment capability of Soft Normally Open Points (SNOP) is used to interconnect the low-voltage power consumption sides of the two transformers in the distribution network, replacing the traditional tie switch, improving the power quality and system reliability. On the basis of the back-to back Voltage Source Converter(VSC) circuit, the energy storage system is added as the topology of the SNOP, which improves the reliability of the system and ensures the safety and reliability of energy exchange under AC-DC AC conversion. A mathematical model is established according to its topology structure, the control strategy under the double closed-loop control structure is studied, and its control strategy is comprehensively considered in combination with the energy storage unit to ensure the compatibility of the energy storage unit. Finally, MATLAB simulation is used to verify the correctness and reliability of the energy storage SNOP system theory under the dual closed-loop control strategy. The test results show that the energy storage SNOP can well interconnect the loads on both sides of the transformer to relieve the heavy load.