Phasor Measurement Techniques.- Phasor Estimation of Nominal Frequency Inputs.- Phasor Estimation at Off-Nominal Frequency Inputs.- Frequency Estimation.- Phasor Measurement Units and Phasor Data Concentrators.- Transient Response of Phasor Measurement Units.- Phasor Measurement Applications.- State Estimation.- Control with Phasor Feedback.- Protection Systems with Phasor Inputs.- Electromechanical Wave Propagation.

Synchronized Phasor Measurements and Their Applications

Hawaii International Conference on System Sciences

Frequency dynamics is one of the most important measures of an electrical power system status. To better understand power system dynamics, an accurately measured wide-area frequency is needed. The concept of building an Internet-based real-time GPS-synchronized wide-area frequency monitoring network (FNET) was proposed in 2000 by Qiu et al., and this concept has been realized. The FNET system consists of frequency disturbance recorders and an information management system. The FNET has made the synchronized observations of the entire U.S. power network possible with very little cost for the first time. This paper summarizes the implementation of the FNET system and shows some preliminary observations and analyses of the data that have been collected from the FNET.

Power system frequency monitoring network (FNET) implementation

Phasor measurement units (PMUs) are rapidly being deployed in electric power networks across the globe. Wide-area measurement system (WAMS), which builds upon PMUs and fast communication links, is consequently emerging as an advanced monitoring and control infrastructure. Rapid adaptation of such devices and technologies has led the researchers to investigate multitude of challenges and pursue opportunities in synchrophasor measurement technology, PMU structural design, PMU placement, miscellaneous applications of PMU from local perspectives, and various WAMS functionalities from the system perspective. Relevant research articles appeared in the IEEE and IET publications from 1983 through 2014 are rigorously surveyed in this paper to represent a panorama of research progress lines. This bibliography will aid academic researchers and practicing engineers in adopting appropriate topics and will stimulate utilities toward development and implementation of software packages.

Synchrophasor Measurement Technology in Power Systems: Panorama and State-of-the-Art

This paper presents a new smart grid infrastructure for active distribution systems that will allow continuous and accurate monitoring of distribution system operations and customer utilization of electric power. The infrastructure allows a complete array of applications. The paper discusses four specific applications: a) protection against downed conductors; b) load levelization; c) loss minimization; and d) reliability enhancement.

Smart Grid Technologies for Autonomous Operation and Control

This paper introduces the new concept of multi-converter (three or more) voltage-sourced-converter (VSC) based FACTS devices as well as DC "control sub-networks". A control subnetwork is defined as a multi-terminal DC transmission system utilizing a number of series and shunt converters connected together and embedded in the AC power system for ultimate control capability. A special case consisting of three converters, namely, the generalized unified power flow controller (GUPFC) is discussed in detail. A fundamental frequency model of the GUPFC and its controls is developed in EMTP and used to demonstrate its performance and capability in a test power system. It is shown that this GUPFC consisting of one shunt converter and two series converters is capable of simultaneously controlling five power system quantities, i.e., the bus voltage at a substation and the real and reactive power flows on two lines exiting the substation. Test results are presented indicating the controller performance for reference tracking and in response to a three-phase fault on the system.

Multi-converter FACTS devices: the generalized unified power flow controller (GUPFC)

A technique for laboratory characterization of instrument transformers designed for transmission level voltage and current measurements is presented. The technique is also extended to transient event recorders (TERs). The objective of the method is to determine the suitability of existing substation instrument transformers for harmonic measurements, particularly in the frequency range of 60 to 1500 Hz covering the first 25 harmonics. Specifically, the following characteristics are of interest: transfer function magnitude and phase, linearity, and sensitivity of the frequency response to burdens. The measurement technique is based on exciting the instrument transformer primary with an impulsive waveform. Both input and output waveforms are recorded using laboratory grade probes and digitizers. Digital signal processing techniques are used to compute the instrument transformer frequency response. Several voltage transformers and current transformers in the 230 kV-765 kV voltage range were tested. The results are described. >

Transmission level instrument transformers and transient event recorders characterization for harmonic measurements

State estimation has been introduced to power systems and implemented in the 60s, using a single frequency, balanced and symmetric power system model under steady state conditions. This implementation is still prevalent today. The single frequency, balanced and symmetric system assumptions have simplified the implementation but have generated practical problems. This paper examines these simplified assumptions and their impact on the state estimation performance. It provides a theoretical basis for the well-known fact that the reliability of the state estimator algorithms has been below expectations. Specifically, sensitivity analysis methods are used to quantify the impact of modeling simplifications and measurement schemes on the performance of state estimation. The results clearly illustrate that the traditional state estimation algorithm is biased. These biases affect the accuracy of state estimation and its convergence characteristics.The paper also reviews the traditional state estimation approach against recent technological advances that have enabled synchronized measurements. The implications and possibilities of this new technology are discussed in this paper. Specifically, an example application of the new technology for a Three Phase State Estimator is described. A power system state estimation based on a) multiphase model, b) voltage and current waveform measurements, and c) synchronized measurements is formulated. The paper focuses on the following: a) modeling, b) implementation, c) observability and d) performance. The overall performance of the system is described in terms of confidence level versus error. These concepts are illustrated with simple systems. In addition, we demonstrate the performance of the proposed methods on an actual system (New York Power Authority system) using actual synchronized measurements. The paper concludes with a commentary on the implications of improved state estimation methods on the security/reliability monitoring and control of an electric power system.

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Power system state estimation: modeling error effects and impact on system operation

Multifunctional synchronized measurement network

In 1992, the New York Power Authority (USA) and the other Empire State Electric Energy Research Corporation member electric utilities initiated the deployment of a network of power system synchronized measurement units using phasor measurement technology on the New York State high-voltage transmission system. This article defines the current and future status of the measurement network, featuring its harmonics measurement and disturbance monitoring.

S. Zelingher

Papers

Multi-converter FACTS devices: the generalized unified power flow controller (GUPFC)

Transmission level instrument transformers and transient event recorders characterization for harmonic measurements

Power system state estimation: modeling error effects and impact on system operation

Multifunctional synchronized measurement network

Multifunctional synchronized measurement network [power systems]