The phenomenon of transformer magnetizing inrush current has been discussed in many papers throughout the years. A brief review of magnetizing inrush is given to provide the basis of need for transient testing. Previous studies have shown that inrush currents contain harmonic components of the fundamental waveform. Conventional philosophy has been to utilize the second harmonic current to provide ...

For pt.I see ibid., vol.112, no.1, p.134-43 (1997). Part I presented practical calculations and novel techniques for collecting performance data from protective relays. Standard definitions were presented for availability, dependability, security, hardware and relaying MTBF, and other measures. Part II gives practical guidelines and complete examples of actual data collection procedures. It focuses on methods for users to compile exposure counts needed for the novel security measurement. Also reasons for collection and uses for the statistical results are described.

The paper presents practical calculations and novel techniques for collecting performance data from protective relays. The methods are focused on, but not limited to, microprocessor-based tcansmission line relaying system. 1. Imprecise definition of the measures from a statistical point of view. 2. Varying attitudes or training of field personnel who must realrd the data. Standard definitions are presented for Availability, Dependability, Security, Hardware MTBF, Relaying MTBF, Repair Tlme, and other measures of interest for specific relay types. The paper explains the novel concept of Exposures, the key to a standardized security measure. A companion paper, Part I1 - Collection and Uses of Data, gives practical guidelines for gathering and calculation of results. With these standard measures, relay users will be able to compile the first consistent industry-wide data base for relay performance assessment.

This paper summarizes research and operating experience related to the effects of geomagnetically induced currents (GIC) on protective relaying. It shows that if the GIC causes high levels of harmonic distortion, there is a risk that the conventional protection system may not provide adequate protection for the capacitors, transformers, and generators. It recommends methods to reduce the risk of false tripping and the risk of failure to protect the power apparatus.

Differential relays are used extensively to provide protection for power transformers. Several issues must be considered in their application to ensure adequate protection. These include transformer magnetizing inrush current, relay burden and current transformer performance. The use of low ratio current transformers in high magnitude fault applications can produce distorted secondary waveforms to the relay whose performance may be directly affected. There is also a relationship between the magnetizing inrush and current transformer performance which may affect the operation of the differential relay. This paper discusses these specific applications and the testing of a transformer differential relay under conditions of saturated CTs using the Electro-Magnetic Transient Program (EMTP)

The heating effects at the end-ring connection areas of the rotor due to the harmonic current generation of a saturating unit transformer from geomagnetic induced currents (GIC) on the transmission system have been calculated from observed data and from EMTP studies sponsored by the Electric Power Research Institute. These calculations show that damage may occur during strong GIC storm activity. This damage can occur from unit transformer saturation or other transformers in the system near the generator. The possibility of damage should be monitored during strong GIC storms through the use of appropriate negative- sequence current monitoring and alarms.

A summary of 90 responses to a survey on the use of adaptive functions in protective relaying systems is given. The survey was developed by Working Group K8 of the Substation Protection Subcommittee of the IEEE Power System Relaying Committee. This paper presents some background on the concept of adaptive protection, summarizes the questionnaire and gives an analysis of the questionnaire responses. Section A of the questionnaire which concerns satisfaction with existing relaying schemes is summarized in two figures. Section B of the survey which outlines 16 possible adaptive features is repeated in its entirety. A number of adaptive features suggested by the respondents are also analyzed.

This paper has been prepared to aid in the effective and uniform application of single-phase tripping and auto-reclosing of transmission lines. The benefits of application, relaying techniques, performance, and statistics will be discussed. The paper covers areas such as system stability, single-phase tripping and auto-reclosing, methods of secondary arc extinction, and related system requirements.Descriptions of the various devices, definitions of terms, and references to other technical publications have been included to make the paper useful not only to relay engineers, but also to other technical people who are responsible for the installation and operation of such systems.

This paper has been prepared to aid in the effective and uniform application of single-phase tripping and auto-reclosing of transmission lines. The benefits of application, relaying techniques, performance, and statistics will be discussed. The paper covers areas such as system stability, single-phase tripping and auto-reclosing, methods of secondary arc extinction, and related system requirements. Descriptions of the various devices, definitions of terms, and references to other technical publications have been included to make the paper useful not only to relay engineers, but also to other technical people who are responsible for the installation and operation of such systems.

The authors report on and analyze a survey of practices and experiences with time-delay back-up protection associated with unit-connected generators, predominantly rated 100 MVA and above. In addition, application and setting considerations are discussed. The survey covered large unit-connected installations, involving 47 respondents and 6698 unit-years of experience. Phase back-up, negative-sequence overcurrent, and high-side neutral overcurrent protection were considered. The majority of respondents were found to apply all three classes of back-up protection: phase, negative-sequence, and high-side neutral overcurrent

The development and operating features of a computer system providing integrated relaying protection and control of a substation is described. Demonstration systems installed in substations are the culmination of a research effort sponsored by the EPRI in collaboration with the General Electric Co. and Westinghouse Electric Corporation.

Concepts for adaptive protective relaying of transmission lines are presented. These include changes in online relay settings, relay characteristics, or logic in response to power system or environmental changes, or as a result of operating experience. Such changes as line-out or generator-out contingencies, which affect fault current distributions and degrade the system's security level, initiate...

A microprocessor based fault locator is described, which uses novel compensation techniques to improve accuracy. It displays the distance to the fault in percent of transmission line length, for facilitating repair and restoration following a permanent fault. Also, it pinpoints weak spots following transient faults.

An experimental general-purpose process-control digital computer system provides high-speed phase-and ground-distance fault protection of one 230 kV transmission line. The stored program performs all of the relaying functions using the output of an analog-to- digital converter which reads the instantaneous value of the power- system currents and voltages. Model line tests described in a companion paper (II -Test Results) form the basis for preliminary performance evaluation. An automatic oscillograph and diagnostic programs will allow a study of field performance.

An experimental general-purpose process-control digital- computer system described in a companion paper (I-System Description) provides high-speed phase-and ground-distance fault protection of one 230 kV transmission line. The stored program performs all of the relaying functions using the output of an analog-to- digital converter which reads the instantaneous value of the power- system currents and voltages. Model line tests described here form the basis for preliminary performance evaluation. An automatic oscillograph and diagnostic programs will allow a study of field performance.