信息物理环境下基于电力电子变压器的跨台区光伏消纳策略

Photovoltaic consumption strategy across multiple transformer districts based on PET under cyber physical system

高比例光伏接入低压配电网易导致潮流反转和电压越限问题。在基于电力电子变压器(PET)互联的交直流配电网中,通过PET之间的功率互济实现光伏消纳,可有效降低潮流反转和电压越限的概率,如何协调交互功率是关键问题。配电网信息物理系统(CPS)集中控制可实现优化分配,但大规模配电网中难以保证通信质量。为此,提出了一种基于改进下垂特性的双模式自适应控制(DBAC)方法,以直流母线电压为全局变量,以各台区PET的端口状态为局部变量,通过引入传输因子,实现PET端口在发送或接收功率模式之间的平滑切换;通过引入不平衡因子,实现光伏功率在接收台区之间按需分配;无需跨台区通信和集中控制,即可实现跨台区PET之间的功率互济。为了验证所提策略的正确性和有效性,构建了由先进配电网小步长仿真机、OPNET和配电主站组成的配电网CPS仿真平台,建立了基于PET的交直流配电网信息物理模型。仿真算例的结果验证了所提DBAC方法可实现高比例光伏跨台区消纳。

The access of high proportion of PV(PhotoVoltaic)to low voltage distribution network can easily lead to problems of power flow inversion and voltage out-of-limit.In the AC/DC distribution network based on PETs(Power Electronic Transformers),PV consumption can be realized through the mutual power between PETs,which can effectively reduce the probability of power flow inversion and voltage out-of-limit.How to coordinate the interactive power is the key problem.Centralized control of distribution network CPS(Cyber Physical System)can realize optimal allocation,but it is difficult to guarantee communication quality in the large-scale distribution network.Therefore,a DBAC(improved Droop characteristics-based Bi-mode Adaptive Control)method is proposed,which takes DC bus voltage as global variable and PET’s port state of transformer district as local variable.The smooth switch between the sending and receiving power modes of PET port is realized by introducing the transfer factor.The unbalanced factor is introduced to realize the allocation of photovoltaic power among receiving transformer districts according to demand.Even if without communication across multiple transformer districts and centralized control,PET power coordination can be realized.The distribution network CPS simulation platform composed of advanced distribution network simulator,OPNET and distribution master station is built,and the cyber physical model of AC/DC distribution network based on PET is established to verify the correctness and effectiveness of the proposed strategy.The results of simulation example show that the proposed DBAC method can realize the high proportion of PV consumption across multiple transformer districts.