State estimation technique for distribution networks

From the viewpoint of monitoring the distribution network can be divided into operatively observable and unobservable part. The observable part is controlled and monitored by SCADA. Generally the data available with the help of SCADA will need correction by means of state estimation technique. For supporting the estimation procedure additionally the automatic meter reading (AMR) data from the unobservable part of the distribution network is needed. The target of state estimation is to refine the measuring data, but more specifically to clarify significant measuring errors and mistakes. Usually the redundancy of data required for estimation is not available in distribution networks - the number of measurements is not essentially bigger or is even smaller than the number of main state parameters. It is possible to resolve this problem with the help of an essentially perfect mathematical load model, which can be used for calculation of all load values and characteristics at any time.