Joerg Blumschein

Practical Experience with PMU System Testing and Calibration Requirements

New data acquisition technologies, such as phasor measurement units (PMU), have been implemented in recent years to operate the power system with more reliability and control by improving the protection schemes like line differential protection or damping the inter-area oscillations. The present standard IEEE C37.118 only provides general information about the testing conditions and requirements, without giving any specifics.. To create the PMU data function for the applications and thereby make the power system more reliable, the appropriate PMU test standards have to be developed and disseminated. Future testing methods should ensure that units from different manufacturers are tested identically and function properly under different repeatable test scenarios and test stand set up conditions. This paper presents experiences from tests of PMU accuracy and calibration conducted in Europe and the USA, which will facilitate the development of future standards. The test stand itself and the test results from the various PMU manufactures are presented, compared and discussed in this paper, taking into account the standardization issues.

Usage of phasor measurement units for industrial applications

The number of phasor measurement unit installation is growing, especially in Europe since a few years. The collected experience of installation requirements and operation conditions as well as their behavior provides much important information about the possible usage of these measurement devices in real power system applications already. Generally, the phasor measurement technology is used to montoring the high voltage level of the power system, especially transmission system already and/or sometimes distribution system as well. This paper describes the investigations made inside of the industrial network to provide the information about possible contribution of the PMUs in such power system operating area.

Experience with PMUs in industrial distribution networks

Phasor measurement units (PMUs) were installed in an industrial distribution network and synchronized measurements taken from the PMU at medium and low voltage during different system states were analyzed. Two cases of system operation were investigated, normal and abnormal operation. Results from up to six PMUs were compared and analyzed for each case.

Automated test procedures for accuracy verification of Phasor Measurement Units

The continuous development of electric power systems characterized by an increasing potential of decentralized energy generation requires high precision measurement technologies for an effective and reliable network monitoring and system state assessment to ensure the high level of present and future security of energy supply. One possibility to capture system parameters, which has been established primarily within transmission networks, is the use of Phasor Measurement Units (PMU). Taking Smart Grid discussions into account, PMU usage in distribution systems, under particular conditions regarding observability aspects should also be considered [2]. The goal of this paper is to introduce the new requirements for PMU measurement accuracy testing according to IEEE standard C37.118.1 [1]. This publication focuses on two things: the development of automated procedures for a certified PMU test bench, and a way to extend an existing test concept according to the new testing regulations. Based on these investigations, exemplary and representative measurements, which were made with this automated test bench are presented and analyzed for one proposed static test scenario.

Precise impedance based fault location algorithm with fault resistance separation

The reactance method with fault resistance separation has been developed in order to determine as precisely as possible the impedance of a fault loop in a transmission or distribution power system line. This method has commonly been used for impedance calculation in case of a single phase-to-earth fault in diverse power system protection applications. New developments in this area have shown that the extension of the method to multi-phase faults is not only possible but also of practical relevance. However, all previous investigations focused on impedance calculation using data from one single side of the power system line. Due to missing data from the remote end, the determined impedance value can deviate from its real value. This research consists in an improvement of this calculation method using data from both the own and the remote line end. This approach uses communication between two measurement units e.g. protection relays, which have the advantage of not requiring a precise synchronization with each other. The additional time invariant parameters of the power system, acquired by each device and transferred to the remote end, allow an exact computation of the fault reactance and fault resistance. In this paper, the derivation of this novel approach as well as experimental results in a fault location application are presented.