Research On Voltage Regulation Scheme Of Distribution Network With Small Hydropower Based On PSASP

With the gradual depletion of fossil energy sources and the introduction of the national concept of combining electricity and ecology in power generation,small hydropower,a green and non-polluting clean energy source,plays an important role in environmental protection and in alleviating power shortages.Small hydropower is generally a run-of-river power station without regulating reservoirs,and T access to the nearby distribution network;small hydropower may lead to high node voltage in the distribution network when it is full during the abundant water period,and may lead to low node voltage in the distribution network when it is low or even stopped during the dry water period.By studying the voltage regulation scheme of distribution network containing small hydropower,the system node voltage can be operated within the specified range,thus ensuring the voltage quality meets the requirements and less power loss in the distribution network.This paper investigates the effect of distribution networks containing small hydropower on the reactive power and active power losses of the lines.After small hydropower is connected to the grid,the characteristics of small hydropower itself will change the network topology of the original power system,which in turn affects its system tidal distribution,thus causing changes in the nodal voltage and active power losses of the line.Using the constant power chain distribution network as a model,we deduce and analyze that the nodal voltage will be affected differently by the location,different capacity and different operation modes of small hydropower access.The IEEE-33 nodal distribution network model is built in the Power System Analysis Software Package(PSASP),and simulations are performed for different access locations,capacities and operation modes of small hydropower.The simulation results show that the overall regulating effect is poor when the access location is at the first section of the line,while the access at the end or the node with more concentrated load,the regulating effect is better;when the capacity of small hydropower is certain,the location of the lowest point of active loss will change with the different access points.Keep the same access location and power factor,the larger the access capacity to the node voltage support capacity,its active loss with access capacity becomes larger and reduce,until its active loss lowest point,and then active loss has a rising trend.When keeping the same capacity and access position,the larger the power factor is in stalled-phase operation,the weaker the lifting capacity of node voltage;in in-phase operation,the smaller the power factor is,the weaker the support capacity of node voltage;stalled-phase operation can effectively reduce the system active loss compared with in-phase operation.Secondly,the research background is based on the period of small hydropower abundance.The full power generation of small hydropower causes the tide reversal,which in turn causes the local node voltage of the system to cross the limit or even seriously cross the limit,thus seriously affecting the normal operation of the system.A 4-node simplified model is established to derive the voltage equation at the load side,and four single voltage regulation measures are derived,namely,small hydropower operation mode voltage regulation,changing transformer ratio voltage regulation,changing network parameters and shunt reactive power compensation equipment,which are analyzed theoretically.Then the IEEE-33 nodal distribution network model is established in PSASP,and the simulation results conclude that small hydropower operation mode regulation,changing transformer ratio regulation,changing network parameters and shunt reactive power compensation equipment can effectively make the system node voltage reduction,and analyze the advantages and disadvantages of single regulation measures one by one.Then,the nodal voltage sensitivity matrix of the distribution network connected to small hydropower in a region is calculated by changing the transformer ratio,regulating the voltage of small hydropower operation mode and shunt reactive power compensation equipment,and then different regulating schemes are proposed according to the regulating effect.Through simulation,the results show that the voltage regulation scheme can effectively suppress the node voltage increase,which provides some reference significance for the voltage adjustment scheme of the distribution network connected to small hydropower in this area.