The article describes the possibilities of using the non-traditional current and voltage sensors ... more The article describes the possibilities of using the non-traditional current and voltage sensors to solve the problem of fault location in terms of digital transformers developed at the Ivanovo State Power Engineering University (ISPEU). Frequency and metrological characteristics of current and voltage sensors are given.
— Rapid fault determination of single-phase earth fault (SPEF) and SPEF location on the line are ... more — Rapid fault determination of single-phase earth fault (SPEF) and SPEF location on the line are extremely important for the speedy elimination of damage and restoring normal operation of the power supply. Effective methods of SPEF determination on the cable lines under voltage do not still exist in medium voltage networks. The electrical values of the transition process that occurs during the breakdown of the insulation can be used for solving the problem of determining the place of single-phase including self-eliminating faults. The best method to study the electromagnetic transients at SPEF in medium-voltage networks and to identify the information parameters, which can be used for distant SPEF determination, is a combination of analytical methods on the basis of simplified models of the electrical networks and the method of computer simulation. Keywords— power distribution networks of medium voltage, determination of the single-phase earth fault place, computer simulation.
Introduction. Damage from the single-phase ground fault SPGF depends on fault localization quickn... more Introduction. Damage from the single-phase ground fault SPGF depends on fault localization quickness and its containment. Protection devices and fault localization devices in networks 6-10 kV for current paths are connected, as a rule, to the cable zero sequence current transformers (CZST) of various types, often working with large secondary loads. The most effective method of both dynamic and static modes and different ways of doing performances SPGF protection devices connected to the cable CZST is mathematical modeling on a computer. Therefore, the development of mathematical models for different types CZST study of both static and dynamic modes of operation of protection devices SPGF is our view, an urgent task. Study of static and dynamic modes of operation CZST. Standard simulation SimPowerSystem blocks do not always allow a sufficiently accurate modeling of electrical and electromagnetic processes in nonlinear systems and devices. Such difficulties may arise in the need to create sufficiently accurate models of nonlinear devices, which include CZST. In these cases, the required accuracy of the model can be derived from the main library blocks Simulink, realizing structural modeling method. The combination of these methods (electrotechnical schematic simulation and structural EPF modeling implemented in other packages for different purposes Simulink) seems to be quite effective method solving problems related to the study of dynamic and static CZST modes in protection devices from SPGF in networks 6-10 kV. About the approaches to the CZST mathematical model construction. Different models [2, 3 and others] can be used for different frequency ranges and different loading situations of the transformer. As long as the transformer is loaded and the frequency of interest is low, fairly simple models can be used: leakage reactance, copper losses, winding capacitances [1]. In the problems associated with the modeling of relay protection, are often applied simple CZST model , in which the magnetic core is described by primary or middle magnetization curve (PMC or MMC) taking into account the hysteresis loss and eddy-currents losses [3 and others]. Such models tend to provide an acceptable accuracy of calculations secondary values for large values of the primary current and low loads of current transformers. CZST in SPGF protection devices should provide the required accuracy of the conversion in high dynamic range of the primary current (ampere units and shares in steady SPGF to hundreds and thousands of amperes in transient regimes) and a more complex shape of the input currents. Therefore, the possibility and conditions of use for modeling CZST descriptions of the magnetic core in the form of PMC or MMC is required additional research. In [4] it is shown that a significant increase in the accuracy of calculations electrotechnical devices with magnetic cores can be obtained by using to describe the processes in the magnetic core and dynamics equations magnetization reversal dynamics equations presented in the following form:
The article describes the possibilities of using the non-traditional current and voltage sensors ... more The article describes the possibilities of using the non-traditional current and voltage sensors to solve the problem of fault location in terms of digital transformers developed at the Ivanovo State Power Engineering University (ISPEU). Frequency and metrological characteristics of current and voltage sensors are given.
— Rapid fault determination of single-phase earth fault (SPEF) and SPEF location on the line are ... more — Rapid fault determination of single-phase earth fault (SPEF) and SPEF location on the line are extremely important for the speedy elimination of damage and restoring normal operation of the power supply. Effective methods of SPEF determination on the cable lines under voltage do not still exist in medium voltage networks. The electrical values of the transition process that occurs during the breakdown of the insulation can be used for solving the problem of determining the place of single-phase including self-eliminating faults. The best method to study the electromagnetic transients at SPEF in medium-voltage networks and to identify the information parameters, which can be used for distant SPEF determination, is a combination of analytical methods on the basis of simplified models of the electrical networks and the method of computer simulation. Keywords— power distribution networks of medium voltage, determination of the single-phase earth fault place, computer simulation.
Introduction. Damage from the single-phase ground fault SPGF depends on fault localization quickn... more Introduction. Damage from the single-phase ground fault SPGF depends on fault localization quickness and its containment. Protection devices and fault localization devices in networks 6-10 kV for current paths are connected, as a rule, to the cable zero sequence current transformers (CZST) of various types, often working with large secondary loads. The most effective method of both dynamic and static modes and different ways of doing performances SPGF protection devices connected to the cable CZST is mathematical modeling on a computer. Therefore, the development of mathematical models for different types CZST study of both static and dynamic modes of operation of protection devices SPGF is our view, an urgent task. Study of static and dynamic modes of operation CZST. Standard simulation SimPowerSystem blocks do not always allow a sufficiently accurate modeling of electrical and electromagnetic processes in nonlinear systems and devices. Such difficulties may arise in the need to create sufficiently accurate models of nonlinear devices, which include CZST. In these cases, the required accuracy of the model can be derived from the main library blocks Simulink, realizing structural modeling method. The combination of these methods (electrotechnical schematic simulation and structural EPF modeling implemented in other packages for different purposes Simulink) seems to be quite effective method solving problems related to the study of dynamic and static CZST modes in protection devices from SPGF in networks 6-10 kV. About the approaches to the CZST mathematical model construction. Different models [2, 3 and others] can be used for different frequency ranges and different loading situations of the transformer. As long as the transformer is loaded and the frequency of interest is low, fairly simple models can be used: leakage reactance, copper losses, winding capacitances [1]. In the problems associated with the modeling of relay protection, are often applied simple CZST model , in which the magnetic core is described by primary or middle magnetization curve (PMC or MMC) taking into account the hysteresis loss and eddy-currents losses [3 and others]. Such models tend to provide an acceptable accuracy of calculations secondary values for large values of the primary current and low loads of current transformers. CZST in SPGF protection devices should provide the required accuracy of the conversion in high dynamic range of the primary current (ampere units and shares in steady SPGF to hundreds and thousands of amperes in transient regimes) and a more complex shape of the input currents. Therefore, the possibility and conditions of use for modeling CZST descriptions of the magnetic core in the form of PMC or MMC is required additional research. In [4] it is shown that a significant increase in the accuracy of calculations electrotechnical devices with magnetic cores can be obtained by using to describe the processes in the magnetic core and dynamics equations magnetization reversal dynamics equations presented in the following form:
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