scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Digital differential protection of a generating unit scheme and real-time test results

01 Mar 1977-IEEE Transactions on Power Apparatus and Systems (IEEE)-Vol. 96, Iss: 2, pp 502-512
TL;DR: In this article, an on-line digital computer technique is used for differential protection of a synchronous generator, which provides fault detection and tripping well within half a cycle and is also capable of discriminating between internal and external faults.
Abstract: This paper presents an on-line digital computer technique used for differential protection of a synchronous generator. It provides fault detection and tripping well within half a cycle and is also capable of discriminating between internal and external faults. In the latter case, sufficient restraint signals are generated to overcome maloperation. Further, the scheme is highly reliable even with CT saturation due to heavy through faults on the generating unit. On-line tests using a laboratory synchronous generator show the results for different types of internal and external faults with varying fault incidence inception.
Citations
More filters
Journal ArticleDOI
TL;DR: In this article, a new artificial neural network (ANN) based digital differential protection scheme for generator stator winding protection is described. But the scheme only uses two ANNs, one for fault detection and the other for internal fault classification.
Abstract: This paper describes a new artificial neural network (ANN) based digital differential protection scheme for generator stator winding protection. The scheme includes two feedforward neural networks (FNNs). One ANN is used for fault detection and the other is used for internal fault classification. This design uses current samples from the line-side and the neutral-end in addition to samples from the field current. Fundamental and/or second harmonic present in the field current during a fault help the ANN, used for fault detection, to differentiate between generator states (normal, external fault and internal fault states). Results showing the performance of the protection scheme are presented and indicate that it is fast and reliable.

54 citations

Journal ArticleDOI
TL;DR: Comparative assessment of the proposed scheme in terms of detection time and incorporation of different types of faults with the existing techniques proves its superiority.
Abstract: A new internal fault detection and classification technique for the synchronous generators is presented. First, the presence of an abnormal/fault condition is detected based on the negative sequence component (NSC) of neutral end current. Thereafter, the internal fault and abnormal/external-fault conditions are discriminated by utilizing the instantaneous phase angle between the NSCs of the terminal voltage and current. Subsequently, the internal fault is classified based on phase angle between NSCs of terminal voltage and neutral end current along with the zero sequence component of the neutral end current. Efficacy of the proposed scheme has been verified on a phase domain synchronous machine model developed on the real time digital simulator (RTDS). The results derived from various fault datasets show that the proposed technique is able to effectively distinguish between internal and external faults including special cases, such as current transformer saturation, overloading, and unbalance condition. Further, it provides added capability of detecting and identifying inter-turn faults irrespective of the winding configuration of the generator. Comparative assessment of the proposed scheme in terms of detection time and incorporation of different types of faults with the existing techniques proves its superiority.

32 citations

Journal ArticleDOI
TL;DR: In this paper, an on-line digital computer technique for the protection of a generator against internal asymmetrical faults is described, which relies on the detection of a second harmonic component in the field current at the onset of a fault in the armature winding.
Abstract: An on-line digital computer technique for the protection of a generator against internal asymmetrical faults is described in this paper. The proposed technique relies on the detection of a second harmonic component in the field current at the onset of a fault in the armature winding. Discrimination against external faults is achieved by monitoring the direction of the negative sequence power flow at the machine terminals. Tests have been conducted on a laboratory synchronous generator for various types of internal and external faults. Results show that the total time for internal fault detection and tripping is well within half a cycle of the 60 Hz signal. A simple extension to negative sequence relaying and loss of excitation relaying is proposed.

30 citations

Journal ArticleDOI
TL;DR: In this article, a digital technique for detecting internal faults in stator windings of synchronous generators is described, which does not need information concerning the machine parameters and is applicable to all types of generators, irrespective of their size.

26 citations

Journal ArticleDOI
TL;DR: The IEEE Working Group on Generator Protection with Digital Computers surveyed power industry engineers to determine what problems are generally encountered and for which adequate protective devices are not available as mentioned in this paper, and two surveys were conducted: one to identify the problems; and the other to determine how prevalent they are.
Abstract: The IEEE Working Group on Generator Protection with Digital Computers surveyed power industry engineers to determine what problems are generally encountered and for which adequate protective devices are not available. Two surveys were conducted: one to identify the problems; and the other to determine how prevalent they are. The industry responses are briefly reported, the problems identified are described, and the feasibility of using digital processors to alleviate them is examined. >

21 citations

References
More filters
Journal ArticleDOI
TL;DR: In this paper, the authors describe the research and development work being done at the AEP Service Corp. on digital computer applications in EHV substations, including relaying of transmission lines and other power system equipment, station alarm monitoring and data logging, oscillography, and supervisory control functions.
Abstract: This paper describes the research and development work being done at the AEP Service Corp. on digital computer applications in EHV substations. Relaying of transmission lines and other power system equipment, station alarm monitoring and data logging, oscillography, and supervisory control functions are considered for possible computer implementation. A new algorithm for computing the impedance as seen from the terminals of a faulted transmission line is presented. Results obtained with the new algorithm for faults simulated with a model transmission line are included in the paper. Field experience obtained from operating a minicomputer in an EHV substation is also described.

100 citations

Journal ArticleDOI
TL;DR: An experimental general-purpose process-control digital computer system provides high-speed phase-and ground-distance fault protection of one 230 kV transmission line and an automatic oscillograph and diagnostic programs will allow a study of field performance.
Abstract: 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.

82 citations

Journal ArticleDOI
TL;DR: The principles of a method of transformer protection by digital computer are described, which is essentially an adaptation ion of harmonic-restraint differential protection.
Abstract: The principles of a method of transformer protection by digital computer are described. The method is essentially an adaptation ion of harmonic-restraint differential protection.

80 citations

Journal ArticleDOI
TL;DR: In this paper, a digital computer program for the protection of a three-phase transmission line is described, which detects the presence of a disturbance, classifies the fault into one of six fault types and determines the modulus and phase of the impedance of the faulted line.
Abstract: The paper describes a digital computer programme for the protection of a three-phase transmission line. This programme detects the presence of a disturbance, classifies the fault into one of six fault types and, using a method of impedance calculation described in an earlier paper, determines the modulus and phase of the impedance of the faulted line. Accuracy of calculation and reliability of detection are determined from fault data for a model transmission line.

56 citations

Journal ArticleDOI
TL;DR: In this article, some of the possible orthogonal sampling techniques for determining instantaneous values of current and voltage to facilitate digital protection of transmission lines are examined by comparison of their frequency spectra.
Abstract: This paper examines some of the possible orthogonal sampling techniques for determining instantaneous values of current and voltage to facilitate digital protection of transmission lines. The relative merits of each technique are examined by comparison of their frequency spectra. Tests to verify the results of the analytical analysis are described.

45 citations