Research On Oilfield Micro Grid Load Balancing Control Strategy

The energy crisis and environment pollution have become major issues and grand challenges for human beings.Development and utilization of clean and renewable energy is imperative.Micro-grid technology is one of most effective methods to make full use of renewable energy and solve connection problem of distributed generation system.The operation state of the micro grid mainly includes grid-connected operation and the isolated island operation as well as the switching state between the two operation states.The unbalance between power generated by micro power sources and load demand will lead to system’s instability under different running conditions.In view of the oil field micro grid’s characteristics,this paper put forward a micro source side and load side coordinated load balance control strategy.This dissertation established the oilfield micro-grid model by DIgSILENT simulation software.The micro-grid contains permanent magnet direct drive wind turbine,photovoltaic generator,storage battery,small gas combustion engines and oilfield load models.The result of simulation showed that the established oilfield micro-grid could reflect characteristics of micro sources oilfield power grid.In order to improve the micro-grid transient stability and the dynamic performance of the micro sources,sliding mode additional throttle control based on the extended state observer was added to small gas combustion engines and battery energy storage switching system was modified by state following theory.The simulation results showed that the improvements on the two micro sources can improve system’s transient stability in the process of switching.The support insufficiency of micro sources will lead system’s load unbalance.A load shedding method considering motor’s kinetic energy deviated imbalance and distance was put forward for the load unbalance condition.Oilfield micro source side control strategy and load side load shedding control strategy was combined.The simulation results of the three operation status which include grid-connected operation status,isolated island operation status as well as the switching state from grid-connected operation status to isolated island operation status showed that the proposed load balancing control strategy could ensure the safety and smooth operation in different running status.