Development and field testing of a closed-loop adaptive powerfactor controller

A continuing effort to develop an effective, reliable, and inexpensive adaptive power factor controller (APFC) is reported. The APFC can adaptively compensate the reactive power of rapidly varying loads without adding harmonics or transients to the power system. Previously, an open-loop APFC, sized at 50 kVAr, has been built and installed at a field site in Southern California Edison territory. Based on thousands of hours of field operation, the APFC has been substantially modified to improve its reliability and effectiveness. The new design is called CL-APFC. It has a number of features that makes it more suitable for harsh environment, such as voltage fluctuations, voltage harmonics, and component failures. The latest design of a closed-loop APFC, sized at 300 kVAr, is reported, and the results of the field tests are demonstrated     

Development and Field Testing of an Adaptive Power Factor Controller

The Adaptive Power Factor Controller (APFC) is a device that switches capacitors electronically to achieve almost unity power factor at the point of installation. It was designed and developed at the University of Washington (UW), and is being tested at the R&D facility of the Southern California Edison Company (SCE). It is particularly intended for loads with dynamically varying reactive power demands such as induction generators in wind power stations, or cyclically changing loads such as induction motors in process industries. It is also ideally suited for improving the power factor profile of a distribution line. The purposes of this paper are two-fold: to explain the most recent design of the 50-kVAR APFC and to report the results of the field testing program on the device after it was installed at the terminals of a 50-kW three-phase induction generator located at the Dever Wind R&D site of SCE.     

An online dispatcher training simulator function for real-timeanalysis and training

Today's power systems have become so complex that it is not easy for the system dispatcher to realistically predict the results of outages. The situation is compounded whenever the power grid is not in its “normal” configuration due to maintenance switching or equipment failure. The authors feel that the dispatcher training simulator (DTS) is an excellent tool that can be used to teach the dispatcher how to react under these conditions. In this paper, the authors present an on-line implementation of the DTS which allows the user to: initialize the DTS to an EMS disturbance using data that was captured at the time of the disturbance; and place the DTS in a playback mode and go back to specific times in the scenario. The former feature allows the analyst to investigate EMS disturbances and then train the various dispatchers to be able to recognize such disturbances and to recover from them when they occur. The latter feature allows the instructor (with the trainee) to review and re-experience desired portions of the scenario. It is the authors' feeling that these two features will help the EMS operational staff understand their power system better and help their dispatchers in dealing with operational problems associated with the proper running of the system     

An online implementation of transient stability in a dispatchertraining simulator

An integrated online transient stability program in the power system dispatcher training simulator (DTS) environment is presented. The DTS stability simulation completes the training system by allowing engineers and training specialists preparing the various scenarios with an opportunity to validate the events sequence for each scenario and to review and evaluate the operator's performance during a training session. The simulation can be directly initialized from the DTS state. The computer program uses the same models which are used in the DTS augmented by the extra modeling needed for the transient capabilities of the generators and DC systems. The interactive user interface is compatible with the DTS/energy management system environment. The output events of the simulation can be directly inserted into the events database of the DTS. Easy data entry capabilities for model building exist. Data security and organization via a database management system is provided. The results of testing are very favorable under various system conditions     

Design of variable structure voltage regulator using poleassignment technique

In a power system, the role of a generator voltage regulator is to ensure that the output voltage is maintained within an acceptable threshold. In this paper a voltage regulator is proposed. The design of this regulator is based on both variable structure control theory and a pole assignment technique. The performance of the proposed regulator has been compared to that of the realistic regulator system proposed by the IEEE Committee on Excitation Systems. The results are discussed, and the pertaining recommendations are given