Distributed Control Method for Economic Dispatch in Islanded Microgrids With Renewable Energy Sources

This paper investigates the issues of the distributed energy management problem (EMP) of Microgrids in the presence of communication delays. To address this issue, a consensus-based distributed algorithm is proposed to integrate the economic dispatch and demand response, which can optimally assign the energy among generation units and load units with the objective of maximizing the total social welfare of the power system. Different from existing energy management algorithms, a nonuniform time-varying delays model is considered and embedded into the design of our algorithm, such that each unit can achieve collaborative optimization without the requirement of fixed delays information, which has both theoretical merits and practical engineering value for the efficient and stable operation of Microgrids. Moreover, it is proved that the proposed algorithm can converge to the optimal solution under some sufficient conditions. Finally, the correctness and effectiveness of the proposed method are validated by several simulation results.

Section: Introductionmentioning

confidence: 99%

Distributed Optimal Energy Management for Microgrids in the Presence of Time-Varying Communication Delays

Huang

Liu

2019

“…It is difficult and expensive to tackle these problems through upgrading lines and increasing Var equipment. Therefore, it is necessary to study new method of Volt/Var optimization and control (VOC) to solve series of problems for high proportion integration of DGs [9], [10].…”

Section: Introductionmentioning

confidence: 99%

Two-Layer Collaborative Architecture for Distributed Volt/Var Optimization and Control in Power Distribution Systems

Wang

et al. 2019

For large-scale distribution networks (DNs) with distributed generations (DGs), the conventional centralized Volt/Var optimization and control (VOC) have high demand for online computing resources and efficiency. This paper proposes a new decision-making method for the distributed VOC (D-VOC) based on a two-layer collaborative architecture. First, for a distributed equivalent load system with on-load tap changer (OLTC), this paper studies how to minimize the active power loss and reach the target voltage of load side for the equivalent load system. Second, a concept of virtual soft controller (VSC) is presented based on the distributed equivalent load system, and the local optimal control strategies of VSCs are designed to realize the D-VOC in DNs. On this basis, a two-layer collaborative architecture for the D-VOC is designed. VSCs could be built in virtual or real deployment at nodes where reactive power sources or reactive power compensation devices are equipped, and they are at the bottom layer of the architecture. VSCs upload their distributed decision results to the local control center (LCC) which is at the top layer of the architecture. The LCC systematically verifies and authorizes each VSC to execute its own operational instruction. Case study on the modified PG & E 69-bus distribution grid shows that the method is feasible and has satisfactory efficiency. INDEX TERMS Distribution network, distributed optimization and control, reactive power, voltage, twolayer architecture, virtual soft controller.

“…In distributed computing research, distributed control is widely applied in the scheduling of the micro-gird [10], [11], and for scheduling with larger-scale flexible loads, the distributed algorithms based on the alternating direction method of multipliers and game theory are verified to be effective. Rivera et al [12] formulated a versatile and scalable distributed convex optimization framework, which in simulation scheduled a million flexible loads to fill system valleys within 30 minutes.…”

Section: Introductionmentioning

confidence: 99%

An Equivalent Aggregated Model of Large-Scale Flexible Loads for Load Scheduling

Zhou

Cui

et al. 2019

The popularity of smart applications enables the large-scale integration of flexible loads to power systems, which poses a considerable challenge to system scheduling. Focusing on scheduling optimization with large-scale flexible loads, this paper proposes the equivalent aggregated method for flexible loads, which converts a large number of flexible loads into a few equivalent models to participate in system scheduling. In order to establish the equivalent model, flexible loads are grouped based on their parameters such that loads with the same or similar parameters are clustered into the same group. Then, the equivalent model for each group is established, a proof of the equivalence relationship between the original model and the equivalent model is provided, and the upper bound of equivalence deviations is estimated. The whole equivalent aggregated model is expressed as the sum of equivalent models of all groups. Afterwards, a new approach of applying the equivalent aggregated model to system scheduling is proposed. Case studies show that the equivalent aggregated model can effectively schedule large-scale flexible loads to shave the peak and fill the valley, with small equivalent deviations and fast calculation speed. This validates the proposed model and demonstrates its promising applications to large-scale load scheduling.