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The selection of a grounding configuration and design of a grounding impedance is of vital importance for the stability and functionality of power systems, including industrial and commercial power systems. These key aspects of grounding systems have been the subject of various standards, industrial codes, and recommended practices. In this article, a review, modeling, and analysis of different grounding system designs are provided. The different grounding system design discussed in this article is compared in terms of the ground potential, ground currents, and overvoltage during ground faults. The various grounding system designs are implemented for power systems components in order to assess their capabilities and performance. Several tests are conducted for ground faults, when different grounding system designs are used. Test results show that some grounding system design can limit ground currents, with minor effects on ground potentials. Other grounding system design can limit ground potentials, while fail to limit ground currents. [ABSTRACT FROM AUTHOR]

This article presents the implementation and performance testing of a bus-differential protection for buses, which interconnect battery storage systems (BSSs). The proposed bus-differential protection is based on employing the α β 0 components of the apparent powers flowing in all branches of the protected bus. The α β 0 components of the apparent powers are employed due to their ability to accommodate changes in the power flow direction in the branches connected to the protected bus. The apparent powers are determined using the measured voltage and currents in all branches connected to the protected bus. The proposed α β 0-based bus-differential protection is implemented and tested for internal and external faults, which are created during the charging and discharging of BSSs. Test results demonstrate the ability of the proposed α β 0-based bus-differential protection to initiate fast, accurate, and reliable responses to internal and external faults in the protected bus. Observed response features of the proposed protection are found to have minor sensitivity to the mode of operation of the BSS (charging and discharging), fault location (internal and external), and/or fault type. [ABSTRACT FROM AUTHOR]

This paper presents the performance evaluation of the digital modular protection for grid-connected battery storage systems (BSSs). The tested digital protection is designed using multiple digital relays that are located at different parts of the protected BSS. Each digital relay is featured with a phaselet-based fault detection to ensure accuracy and response speed. The outputs of the digital modular protection are control signals that operate circuit breakers in the charging and discharging circuits, battery units, and the point of common coupling. The tested digital modular protection is implemented for performance evaluation using a 250-kW grid-connected BSS that is charged through a $3\phi$ ac–dc power electronic converter (PEC) and discharged through a $3\phi$ dc–ac PEC. Performance results show that the digital modular protection can initiate fast, accurate, and reliable responses to faults occurring in different parts of the protected BSS. These response features have a negligible sensitivity to the type and/or location of faults, the charge/discharge mode of operation, and/or levels of power exchange with the host grid. [ABSTRACT FROM PUBLISHER]

This paper presents the application of the multiframe digital interconnection protection for cogeneration systems. The multiframe digital interconnection protection is constructed from two frequency main frames; one frame to detect islanding events and the other frame to detect faults on either side of the point-of-common-coupling (PCC). Islanding events are detected based on the wavelet packet transform high-frequency subband, which is extracted from the $d\!-\!q$-axis components of the instantaneous $3\phi$ apparent powers determined at PCC. The detection of faults, on either side of PCC, is achieved by extracting the magnitudes and phases of the high-frequency contents present in PCC currents. The high-frequency contents present in PCC currents are extracted by a phaselet filter bank that is composed of six digital high-pass filters, which are designed to implement six phaselet subframes. The multiframe digital interconnection protection is experimentally tested on a 3.6 kVA cogeneration system for islanding events, different faults on both sides of PCC, and nontransient conditions. Test results demonstrate the ability of the proposed interconnection protection to initiate accurate, fast, and reliable responses to various types of transient disturbances. [ABSTRACT FROM AUTHOR]

This paper develops and tests a new method for managing the responses of multiple digital relays employed in interconnected permanent-magnet generator (PMG)-based wind energy conversion systems (WECSs) with battery storage. The developed method utilizes digital relays (modules), each of which provides protection for a specific location of the PMG-based WECS and battery storage. The outputs of the developed digital protection scheme are trip signals to operate circuit breakers in PMG-based WECS, battery storage, and point-of-common-coupling. The modular digital protection is implemented for experimental testing on a 5-kW PMG-based WECS that has a 2.3-kW battery storage. Test results show that the developed protection can offer fast, accurate, and reliable responses to faults occurring in different parts of the tested WECS and battery storage. In addition, test results show that the modular digital protection has minor sensitivity to the location of faults, charge/discharge cycles of the battery storage, and/or levels of power delivery to the host grid. [ABSTRACT FROM AUTHOR]

This paper develops and experimentally tests the performance of a digital interconnection protection for grid-connected wind energy conversion systems (WECSs). The developed protection is constructed by two frequency frames to process voltages and currents measured at the point-of-common-coupling (PCC). The first frequency frame is set to process the d-q-axis components of the instantaneous 3\phi apparent powers ( sd and sq) determined at PCC. This processing of sd and sq aims to extract their high-frequency subband contents in order to detect the islanding condition. The second frequency frame is set to extract the high-frequency contents (magnitudes and phases) present in the $3\phi$ currents flowing through PCC. These high-frequency contents provide signature information for detecting faults occurring on either side of PCC. The multiframe digital interconnection protection is implemented for performance evaluation on two different WECSs operated in grid connection. Performance results show accurate and reliable detection and identification of the islanding condition and faults occurring on either side of PCC. In addition, performance results show that the multiframe digital interconnection protection has minor sensitivity to the type, structure, ratings, and levels of power delivery to the host grid. [ABSTRACT FROM PUBLISHER]

This paper presents the real-time implementation and experimental performance evaluation of the phase-based digital protection against arc flash faults. The tested digital protection is based on extracting the high frequency components from fault currents triggered by an arc flash fault. The desired high frequency components are extracted using a filter bank that is composed of five exponentially modulated Kaiser window-based high-pass filters (HPFs). The structure of the used filter bank is selected to ensure extracting high frequency components with nonstationary phases, which represent a unique signature of arc flash faults. Such a signature allows detecting and identifying arc flash faults, as well as initiating responses against such events. The performance of the phase-based digital protection is experimentally evaluated for a laboratory $3\phi$ system that supplies linear, nonlinear, and dynamic loads. Test results demonstrate fast, accurate, and reliable detection, identification, and response to arc flash faults. In addition, test results show that the phase-based digital protection has minor sensitivity to the type of arc flash fault or supplied loads. [ABSTRACT FROM PUBLISHER]

This paper proposes a new approach for detecting and identifying arc flash faults in power systems. The proposed approach is structured to extract the phases of transient frequency components present in arc flash fault currents. The desired phases can be extracted by processing fault currents using a modulated filter bank that is composed of high-pass finite impulse response (FIR) filters. These filters are designed by using the Kaiser window method to achieve linear phase responses. Extracting the phases of transient frequency components, present in arc flash fault currents, can provide signature information for accurate and fast detection and distinguish of an arc flash fault. The proposed phase-based approach is implemented for off-line testing to evaluate its performance. Test cases of parallel and series arch flash faults are conducted for supplying linear, nonlinear, and dynamic loads. Simulation and off-line results demonstrate the validity, accuracy, speed, and reliability of the phase-based approach to detect and distinguish arc flash faults with minor sensitivities to the load type and arch flash type. [ABSTRACT FROM AUTHOR]

Ground faults are among the major causes of disrupting the safe, secure, stable, and profitable operation of doubly fed induction generator (DFIG) based wind energy conversion systems (WECSs). On one hand, minimizing the possible damage in a DFIG-based WESC, caused by ground faults, requires accurate detection and fast response of ground protective devices. On the other hand, the responses of ground protective devices are highly dependent on ground currents and potentials, especially during high-impedance ground faults. This paper investigates the influences of grounding configurations on the responses of ground protective devices used in DFIG-based WECSs during high-impedance ground faults. Investigated influences are observed through the ability of ground protective devices, used in DFIG-based WECSs, to quickly and accurately respond to high-impedance ground faults for different grounding configurations. In this paper, the solid, low-resistance, high-resistance, and open grounding configurations are tested for DFIG-based WECS in order to establish comprehensive investigations. The results of the investigations show that the responses of ground protective devices vary depending on ground fault currents, which can have different levels due to the grounding configuration. Moreover, the results of the investigations reveal that the frequency-selective grounding configuration can offer a minimum impact on the responses of ground protective devices used in DFIG-based WECSs. [ABSTRACT FROM AUTHOR]

One of the requirements for safe, stable, sustainable, and profitable operation of doubly fed induction generators (DFIGs)-based wind energy conversion systems (WECSs) is the accurate and reliable protection against electrical faults, in particular, ground faults. The performance of protective devices employed to achieve this requirement is highly dependent on the grounding configuration of the DFIG-based WECS. This paper investigates impacts of the grounding configuration on the performance of protective devices used to protect DFIGs-based WECSs from electrical ground faults. Investigated grounding configurations include solid grounding, low-resistance grounding, high-resistance grounding, and no grounding. This paper also investigates the use of a capacitor in parallel with a low resistance, as a grounding configuration, to limit ground potentials, reduce ground currents, and minimize impacts on responses of ground protective relays. The impacts of the grounding configurations on protective devices are observed through their ability to identify faults, as well as their speed to respond to identified faults. Simulation and experimental results reveal that adequately designed low-resistance grounding offers the minimum impacts on protective devices used for ground protection of DFIG-based WECSs. [ABSTRACT FROM PUBLISHER]