Ryszard Kowalik

Problems Found During Testing Synchronous Digital Hierarchical Devices Used on Power Protection Systems

This paper examines testing methods and devices for sending data to line protection devices using the synchronous digital hierarchical (SDH) protocol. The paper has arisen as a result of cooperation between the Institute of Power Engineering and the Polish Power Electrical Utility Operator (PSE). The main objective of the tests was to investigate the possibilities of using already installed or new SDH telecommunication devices in power system protection systems. A range of protection functionality tests was considered along with SDH devices tests that focused on certain conditions and possible problems that may occur during normal operating conditions.

Characterization of electrical appliances based on their immitance

The article contains an overview of electrical devices parameters employed in non-intrusive load monitoring system. Most frequently used parameters of household appliances, based on current and power supply voltage waveforms, are presented. On the basis of performed experiments, the impact of the load on the pattern parameters is demonstrated. The new method for characterization of electrical devices based on their immitance parameters is proposed. The new set of parameters, calculated with the use of designed method and evaluated, is discussed.

Overview and test results of modern pilot schemes for coordination of line distance protection relays

The paper presents a short review of pilots schemes, which are available in modern line distance protection relays, and example results of common pilot schemes tests with the testing methods description. Some differences in implementations of selected pilot schemes have been shown for comparison reasons. Distance protection coordination functions have been tested for GE Multilin UR-series devices. Every type of available pilot scheme has been checked in synthetic test and during the real coordination between D60 and D90Plus devices. For POTT scheme, coordination between two L90 protections has been realized by a sort of available different telecommunication link types, for comparison reasons.

Testing methodology of modern digital power system protections

In the paper power system digital relay test types are presented. Different types of analysis to which relay communication systems should be submitted are described. Among them the following can be enumerated: communication control board, communication interface between the device and the local monitoring PC, communication monitoring systems between protective devices. Also a particular attention was paid to the description of tests which should be performed on network-based communication systems (i.e. protection devices using the UCA protocol) both on site and in laboratory conditions. Moreover test procedure of UCA-based devices and the laboratory bench destined for network-based device testing are described. Finally some test examples and their results are presented with the appropriate comments.

A simple real-time simulator for protection devices testing

The submitted paper presents the design of a simple real-time simulator devoted to protection devices tests, whose the operation principle is based on closed feedback loop. The device is the result of a series of scientific projects carried out at the the Protection and Control Laboratory of IEn-PW. The construction, the issues related to the operation principle along with some results of tests performed on the designed simulator are presented in the paper. The software part is based on MATLAB/Simulink package including libraries, while the hardware part consists of measurement cards installed in PC computers, a CMS156 amplifier and a dedicated matching circuit. The last section of the article contains a brief description of the expected possible improvements of the simulator in the future.

Distance protections coordination using the exchange of binary signals in the IEC61850 protocol

The paper presents results of tests investigating the subject of distance protection coordination by exchanging binary signals between substations with IEC61850 protocol. The testing stand, testing methods and devices have also been described. For comparison reasons, the results of the same kind of tests where the SDH network has been used to exchange the information have been described. The paper has arisen on the base of tests performed by Institute of Power Engineering of Warsaw University of Technology on behalf of PSE Operator.

Adaptive phasor estimation technique during off-nominal frequency for numerical relays

ABSTRACT The use of digital multifunction protection relays and their proper integration on the power system and smart grid is an important element. However, the performance of digital relays depends on many factors and needs to be carefully evaluated. These factors may be caused by correct operations with less performance or completely incorrect operations. Frequency deviation is one of those factors which results from unbalanced demand load and generation levels. Load characteristics and generation control response to demand load changes will effect on amount and duration of frequency deviations. Frequency decreases when demand load is higher than generation, whereas it increases when load is less than generation. Protection relays are provided with frequency tracking to reduce the effects of frequency deviations on accuracy of relay decisions. In this paper, traditional frequency tracking technique used on protection relays is modified to give a better performance (less Total Vector Error, TVE) during off-nominal frequency variations. The performance of the proposed algorithm is compared with traditional tracking using Least Square Error (LSQ), and Discrete Fourier transform (DFT) algorithm without any tracking, which are investigated in MATLAB environment.

Next Generation of Power System Protection Automation – Virtual Power System Protections

This paper describes the concept and analysis of virtualization technology and possible virtualization scenarios, which can be used to create a new generation of intelligent electronic devices (IEDs). The overview of the concept was based on solutions used in conventional IT systems. A fully operational working lab environment, in which simulated IED models were implemented, has been successfully tested. Problems associated with environment launch are described. An analysis of the influence of virtual device time synchronization and resynchronization on their correct operations is performed. Time delays of communication when sending GOOSE messages between the IEDs using GOOSE packages are verified.

Adaptive phasor estimation technique during off-nominal frequency

the use of digital multifunction protection relays and their proper integration on power system and smart grid is an important element. However, the performance of digital relays depends on many factors and needs to be carefully evaluated. These factors may be caused correct operations with less performance or completely incorrect operations. Frequency deviation is one of those factors which results from unbalanced demand load and generation levels. Load characteristics and generation control response to demand load changes will effect on amount and duration of frequency deviations. Frequency decreases when demand load is higher than generation, whereas, it increases when load is less than generation. Protection relays are provided with frequency tracking to reduce the effects of frequency deviations on accuracy of relays decisions. In this paper traditional frequency tracking technique used on protection relays is modified to give a better performance during off-nominal frequency variations. The performance of the proposed algorithm is compared with traditional tracking using Least Square Error (LSQ), and Discrete Fourier transform (DFT) algorithm without any tracking, which are investigated in MATLAB environment.

The real-time simulator for protective relays testing using MATLAB/Simulink software

The submitted paper presents a tester designed for testing the protective relays in work conditions close to the real. The device is a simulator operating in real-time of the phenomena taking place in the modeled part of power system. The paper describes the construction (including hardware and software aspects) and operation principle of designed simulator. The MATLAB/Simulink software has been used for modeling the test systems (as parts of the whole power system). Paper includes some example results of distance relay tests performed using designed simulator. In addition, the opportunities for further development of both hardware and software parts of the simulator have also been presented.