Researsh On Coordinated Control Methodology Of Distributed Renewable Power Integrated System

The renewable power has strong volatility, which could threaten the operation of the system, especially when there is high penetration of renewable power. This paper studies the coordinated control methodology of distributed renewable power integrated system. And this paper is focused on the system level coordinated control methodology of distributed wind integrated system. Details are as follows:1) Synthetic wind speed time series is studied. This paper puts forward an advanced first-order Markov chain approach. In this advanced approach, seasonal characteristics and diurnal behavior of wind are modeled by dividing one year and one day into 12 and 4 equal parts, respectively. Also, the relationship between wind and precipitation is taken into account. The comparison between the advanced approach and the original one shows that this advanced first-order Markov chain approach could preserve the autocorrelation property of observed wind speed data well and improve the accuracy of generated wind series as well.2) This paper studies the multi timescale coordinated scheduling methodology of conventional generators. A dual timescale active power coordinated scheduling framework is proposed. And the framework is established in the presence of storage and wind forecast uncertainties and is composed of rolling scheduling, real-time scheduling and storage control. Rolling scheduling is activated every 30 minutes and the renewed forecast is used to modify the day-ahead scheduling curve. Real-time scheduling is triggered every 15 minutes using the renewed forecast to modify the output of balance generators. The mismatch of active power is further balanced by storage. Further, the optimization model of rolling scheduling policy, the optimization model of aggregate output of balance generators and the optimization model of allocation of active power between balance generators are proposed.3) A policy iteration algorithm for deriving the cost optimal policy of aggregate output of balance generators is proposed. First, energy loss and use of fast-ramping generation are selected as the performance metrics. Then, a policy iteration algorithm is developed using Perturbed Markov decision process. And this algorithm has a two-level optimization structure in which both the long-term and short-term behaviors of real-time scheduling policy are optimized. Through comparative numerical experiments, both the performance of the policy iteration algorithm in short-term and long-term are verified and the consistency, robustness, good convergence and high computational efficiency of the proposed algorithm are also corroborated. The performance of dual timescale active power coordinated scheduling framework is also verified under the performance metrics aforementioned.4) An algorithm for deriving the cost optimal policy of rolling scheduling based on active set method is proposed. The initialization method is also put forward. The efficiency of the algorithm is verified via the IEEE 24 bus system. The aggregate output of conventional generators becomes more close to the actual aggregate output of conventional generators after rolling scheduling is activated. The performance of dual timescale active power coordinated scheduling framework is also verified via time domain simulation.