Power switchgear operating characteristics monitoring system

Abstract

The present invention relates to a system for monitoring the operational characteristics of an electric power switch. The system for monitoring the operational characteristics of an electric power switch according to the present invention is characterized in that it includes an electrode sensor that is impregnated in a circular, square or pin-shaped structure inside a conventional insulator constituting the electric power switch, or is separately installed outside in the form of a detachable electrode sensor module, and detects an electrostatic voltage induced when the position of the main contact of the electric power switch moves, and an integrated monitoring means that simultaneously calculates and displays the opening and closing time, three-pole non-simultaneous opening and closing time, stroke and operating speed of each phase of the electric power switch based on the voltage value input from the electrode sensor, and outputs a control signal for an alarm or locking when the calculated output value deviates from a predetermined operational characteristic limit range.

Description

[Technical field]

[0001] The present invention relates to an operating characteristic monitoring system for electric power switches, and more particularly to an operating characteristic monitoring system for electric power switches which monitors operating characteristics during switching, such as the switching time of each phase of the electric power switch, the non-simultaneous switching time of three poles, the stroke, and the operating speed, in real time so as to always ensure switching and breaking performance during use, thereby enabling monitoring and control even from a remote location, and which can transmit an output signal to the outside by detecting the occurrence of a sudden change in the operating characteristic value. [Background technology]

[0002] An electric power switchgear is a device that creates, changes, opens, closes, and breaks an electric circuit in order to efficiently and reliably connect and distribute the electricity produced at a power plant to consumers. It is broadly divided into a general switch that is used for a single purpose, and a switchgear in which a circuit is formed with multiple switches and the system has multiple functions.

[0003] A general switchgear is a power device that cuts off the power supply by switching the load current in the inspection section for line or load inspection in power systems that supply electricity, such as power transmission systems and distribution systems, and then re-supplies the load current stably after the inspection is completed. Depending on the purpose of use, general switchgears can be classified into circuit breakers (CB), load breaker switches (LBS), automatic transfer switches (ATS), automatic section switches (ASS), automatic load transfer switches (ALTS), earth switches (ES), disconnect switches, etc.

[0004] General switchgears are divided into Gas Insulated Switchgear (GIS) and Solid Insulated Switchgear according to the insulation method, and into overhead switchgears that are installed on utility poles to open and close overhead lines, and underground switchgears that are built into earthed metal boxes to open and close underground cables. Currently, molded solid insulated switchgears, which were introduced to prevent global warming, are commonly used as overhead switchgears, and both SF6 gas insulated switchgears and solid insulated switchgears are used as underground switchgears, but they are expected to be replaced by environmentally friendly gas insulated switchgears in the future.

[0005] In terms of the method for extinguishing the arcs that occur when switching on and off current, gas insulated switchgears, which use SF6 gas as an arc-extinguishing medium due to its excellent arc-extinguishing properties, were mainly used in the past. However, when the use of SF6 gas became a concern as it caused global warming, solid insulated switching methods were developed to solve this problem, and since then vacuum interrupters have generally been used.

[0006] In general, Gas Insulated Switchgear (GIS) is a composite switchgear that not only switches load current under normal operating conditions in a power system, but also safely protects the line under abnormal conditions such as accidents and short circuits. It is composed of a circuit breaker (CB), disconnecting switch (DS), earth switch (ES), potential transformer (PT), current transformer (CT), lighting arrester (LA), bus (BUS), etc., housed in a metal case filled and sealed with insulating gas such as SF6 gas, CO2, g3, or dry air.

[0007] Hardware technology for power switchgear is already at a mature stage, and in recent years, there has been intensive development of environmentally friendly technologies such as dry air insulation, epoxy insulation, and environmentally friendly vacuum interrupter technology for increasing the interrupting capacity. There has also been active promotion of efficient asset management of power equipment for trouble-free operation and economical maintenance and replacement of power equipment.

[0008] As the number of switching operations increases according to the period in which a power switchgear is applied to a system and used, the switching operation characteristic values ​​of the power switchgear, such as the switching time of each phase, the non-simultaneous switching time of three poles, the stroke, and the operating speed, change due to deterioration of electrical components, wear of mechanical operating device components, loosening and breakage of bolts, etc. If a power switchgear has operating characteristics different from those at the time of initial installation and no longer operates correctly, the switching and breaking capabilities will decrease, leading to damage and serious failure of power equipment and making it impossible to stably supply power to consumers, so it is very important to monitor and diagnose the switching operation characteristics of the power switchgear.

[0009] When evaluating the soundness of electric power facilities, technical evaluation is performed by periodic inspection to grasp the condition of the facilities and online preventive diagnosis using sensors. The main inspection items for power switchgear include the main circuit characteristics of the power facilities (insulation resistance, contact resistance), the operation characteristics of the switchgear (opening time, 3-pole non-simultaneous opening and closing time, stroke, operation speed), and the current preventive diagnosis items include gas condition monitoring (moisture content, purity, amount of SO2 in gas) and partial discharge measurement. However, since the inspection of power switchgear is performed in a power outage (no voltage) state, the power supply through the power line where the switchgear is installed must be stopped, and therefore, a separate power line must be secured in order to continue supplying power to consumers. In addition, since it is not possible to shut down all power lines at the same time, the inspection must be performed in stages, which increases the human and time costs.

[0010] Therefore, there is a strong demand for the development and application of monitoring technology that can monitor and diagnose the operating characteristics of power switchgears in real time, such as the opening and closing time of each phase, the non-simultaneous opening and closing time of three poles, the stroke, and the operating speed, by using various types of sensors while the voltage is applied during operation. The operating status data of power switchgears collected in real time by sensors is used for evaluating the health of power switchgears by comparing and analyzing the initial data and previously collected data. The analyzed data is not only provided to the asset owner or manager as information for deciding whether to suspend operation and perform maintenance of the equipment, but is also used as information for giving accurate work instructions to on-site workers. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent No. 10-0996138 (November 17, 2010) [Patent Document 2] Korean Registered Utility Model No. 20-0446550 (November 2, 2009) [Patent Document 3] Korean Registered Utility Model No. 20-0418998 (June 9, 2006) Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention aims to provide an operational characteristic monitoring system for a power switch that is capable of monitoring and diagnosing changes in the operational characteristics of a power switch during operation, such as the opening and closing time of each phase of the power switch, the three-pole non-simultaneous opening and closing time, stroke, and operating speed, in real time, by installing an electrode sensor in an impregnated form inside a solid insulator that is a component of the power switch, or by installing a separate, detachable detection electrode sensor module on the outside, and outputting a control signal for warning and locking when the operational characteristics of the power switch suddenly change, based on the characteristic that the voltage induced in the capacitance-type electrode sensor varies depending on the spatial position change of the movable electrode due to the operation of the switch.

[0013] Furthermore, the present invention aims to provide an operating characteristic monitoring system for power switch that is equipped with a communication module to enable communication with an external computer in a remote location, thereby making it possible to easily monitor and control the operating characteristics of a power switch even in a remote location. [Means for solving the problem]

[0014] The power switchgear operation characteristic monitoring system according to the first embodiment of the present invention is characterized in that it includes: capacitance-type electrode sensors that are installed in a circular, rectangular, or pin-shaped structure inside an insulating partition spacer between a circuit breaker unit and a cable connection unit of an insulated switchgear and detect a voltage induced when a movable electrode moves in position due to operation of the circuit breaker; capacitance-type electrode sensors that are installed in a circular, rectangular, or pin-shaped structure inside an insulating partition spacer between a three-terminal switchgear unit (disconnector unit) and the circuit breaker unit of a gas-insulated switchgear and detect a voltage induced when a movable electrode moves in position due to operation of the three-terminal switchgear (disconnector); and integrated monitoring means that is connected to the electrode sensors, converts and calculates signals input from the electrode sensors into digital signals, and simultaneously calculates, diagnoses, and displays the opening and closing times, three-pole non-simultaneous opening and closing times, strokes, and operating speeds of the circuit breakers and three-terminal switches (disconnectors) of the switchgear, and outputs a control signal for warning or locking when the calculated output value deviates from a predetermined limit range of the power switchgear operation characteristics.

[0015] The power switch operation characteristic monitoring system according to the second embodiment of the present invention is characterized in that it includes capacitance-type electrode sensors that are installed in a circular, square, or pin-shaped structure inside and outside an epoxy insulator housing that is located outside a switching unit (vacuum interrupter and blade-type contact) electrically connected to a primary inlet of a general switch and detect a voltage induced when the main contact of the switching unit of the general switch moves up and down or rotates, and an integrated monitoring means that is connected to each of the electrode sensors and converts and calculates signals input from the electrode sensors into digital signals to simultaneously calculate, diagnose, and display the switching time, three-pole non-simultaneous switching time, stroke, and operating speed of each phase of the general switch, and outputs a control signal for an alarm or locking when the calculated output value deviates from a predetermined operating characteristic limit range.

[0016] The power switch operating characteristic monitoring system according to the third embodiment of the present invention is characterized in that it includes an electrode sensor module that is installed in the form of a detachable structure on the outside of the insulating partition spacer that constitutes the gas partition of the power switch and detects a voltage induced during the opening and closing operation of the power switch, and an integrated monitoring means that is connected to each of the electrode sensor modules and converts and calculates signals input from the electrode sensor modules into digital signals to simultaneously calculate, diagnose and display the opening and closing time, three-pole non-simultaneous opening and closing time, stroke and operating speed of each phase of the power switch, and outputs a control signal for an alarm or locking when the calculated output value deviates from a predetermined operating characteristic limit range. Effect of the Invention

[0017] The power switch operating characteristic monitoring system according to the present invention installs circular, square and pin-shaped electrode sensors impregnated inside a solid insulator, which is a component of a conventional power switch, or installs a separate detachable detection electrode sensor module on the outside, so that the operating characteristics of the power switch can be monitored and diagnosed in real time when a voltage is applied and the switch is in operation.

[0018] The power switch operation characteristic monitoring system according to the present invention can display the operation characteristic states of the power switch, such as the opening and closing time of each phase, the three-pole non-simultaneous opening and closing time, the stroke, and the operating speed, in real time in the form of digital values ​​and graphs while the power switch is in operation with voltage applied, and can monitor the operation characteristic states of the power switch from a remote location in real time without the need for an inspector to move to the installation site of the power switch. If the operation characteristics of the power switch suddenly change, a control signal for an alarm and locking can be output to perform alarm and locking control, and the power switch can be replaced and maintained at an appropriate time, thereby preventing accidents and accident spread in the power system and power equipment in advance and ensuring the operational reliability of the power system.

[0019] The power switchgear operation characteristic monitoring system according to the present invention can be utilized for asset management by evaluating and analyzing the health of power equipment by accumulating, collecting, comparing and analyzing data showing the operation characteristics of power switchgears. The analyzed data is not only provided to the asset owner or manager as information for deciding whether to suspend operation of the equipment or to perform maintenance management, but is also used as information for giving accurate work instructions to on-site workers. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a structural diagram of a typical three-phase integrated gas-insulated switchgear. [Figure 2A] FIG. 1 is a structural diagram of a three-terminal switch section of a typical three-phase integrated gas-insulated switchgear. [Figure 2B] FIG. 1 is a structural diagram of a three-terminal switch section of a typical phase-separation type gas-insulated switchgear. [Figure 2C] FIG. 1 is a structural diagram of a circuit breaker section of a typical phase-separation type gas-insulated switchgear. [Diagram 3] FIG. 1 is a structural diagram of a typical solid insulated switchgear. [Figure 4] 1 is a conceptual diagram of a power switchgear operational characteristic monitoring system according to the present invention; [Figure 5A]This is an example in which a capacitance-type electrode sensor of the power switchgear operation characteristic monitoring system according to the present invention is applied to a phase-separation type gas-insulated switchgear. [Figure 5B] This is an example in which the capacitance-type electrode sensor of the power switch operating characteristic monitoring system according to the present invention is applied to a three-phase insulating partition spacer of a three-phase integrated gas-insulated switchgear. [Figure 5C] 1 is an example in which a capacitance-type electrode sensor of a power switch operation characteristic monitoring system according to the present invention is applied to a solid insulated switch. [Figure 6A] In the power switchgear operating characteristic monitoring system according to the present invention, a part (one in the case of a phase separation type) of the embedded metal fitting (nut type) of the insulating partition spacer is replaced with an impregnated, insulated pin-type electrode and used directly as a capacitance-type electrode sensor. [Figure 6B] In the power switchgear operating characteristic monitoring system according to the present invention, an impregnated and insulated pin-type electrode (one in the case of a phase-separated type) is added between the embedded metal fittings (nut type) of the insulating partition spacer and used as a capacitance-type electrode sensor. [Figure 7A] 1 is an example showing a detachable capacitance-type electrode sensor module of a power switchgear operation characteristic monitoring system for application to a phase-separated gas-insulated switchgear according to the present invention. [Figure 7B] 1 is an example showing a detachable capacitance-type electrode sensor module of a power switch operating characteristic monitoring system for application to a three-phase integrated gas-insulated switchgear according to the present invention. [Figure 8A] FIG. 13 is a diagram showing a potential distribution map and an induced voltage of an electrode sensor when a three-terminal switch of a gas-insulated switchgear is in an open state (DS / ES OPEN). [Figure 8B] FIG. 13 is a diagram showing a potential distribution map and an induced voltage of an electrode sensor when a three-terminal switch of a gas-insulated switchgear is in a disconnector closed (DS CLOSE) state. [Figure 8C] FIG. 2 is a diagram showing a potential distribution map and an induced voltage of an electrode sensor when a three-terminal switch of a gas-insulated switchgear is in an earthing switch closed (ES CLOSE) state. [Figure 9A] FIG. 1 is a diagram showing a concept of measuring the opening and closing times of each phase using changes in induced voltage of a capacitance-type electrode sensor that appear when the three-terminal switch unit of the gas-insulated switchgear according to the present invention performs the disconnector close (DS CLOSE), disconnector open (DS OPEN), and earth switch close (ES CLOSE) operations. [Figure 9B] FIG. 1 is a diagram showing a measurement concept of a three-pole non-simultaneous switching time when a circuit is closed and a three-pole non-simultaneous switching time when a circuit is opened by the operation of a three-terminal switch unit of a gas-insulated switchgear according to the present invention. [Figure 10A] 1A and 1B are diagrams showing a potential distribution map and an induced voltage of an electrode sensor when a circuit breaker of a gas-insulated switchgear is in an open state. [Figure 10B] 4A and 4B are diagrams showing a potential distribution map and an induced voltage of an electrode sensor when a circuit breaker of a gas-insulated switchgear is in a closed state. [Figure 11A] FIG. 11 is a diagram showing a change in induced voltage of a capacitance-type electrode sensor due to the gap between a fixed contact and a movable contact when a circuit breaker of a gas-insulated switchgear according to the present invention operates from a closed circuit state to an open circuit state. [Figure 11B] FIG. 1 is a diagram showing a concept of measuring the operating stroke and speed of a gas-insulated switchgear circuit breaker according to the present invention when the circuit breaker performs a switching operation upon receiving an operation command. [Figure 12] 1 is a schematic structural diagram showing the configuration of a monitoring means for monitoring operating characteristics such as the switching time of each phase of the power switchgear according to the present invention, the three-pole non-simultaneous switching time, stroke, and operating speed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The power switch operating characteristic monitoring system according to the present invention is characterized in that it includes a capacitance-type electrode sensor that is installed outside the primary conductor of the power switch and detects the electrostatic voltage induced during the opening and closing operation of the main contacts of the power switch, and an integrated monitoring means that diagnoses the operating characteristics of each phase based on the electrostatic voltage input from the capacitance-type electrode sensor and outputs an alarm or a control signal for locking if a predetermined operating characteristic safety range is exceeded.

[0022] The advantages, features and methods of achieving the present invention will become more apparent from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various forms.

[0023] In this specification, the present embodiment is provided to fully understand the scope of the invention to those skilled in the art to which the present invention pertains, so that the disclosure of the present invention is complete. The present invention is defined only by the claims. Therefore, in some embodiments, well-known components, well-known operations, and well-known techniques are not specifically described to avoid obscuring the present invention.

[0024] Throughout the specification, the same reference numerals refer to the same components. Furthermore, the terms used (referred to) in this specification are used to describe the embodiments, and do not limit the present invention. In this specification, the singular expression includes the plural expression unless otherwise specified. Furthermore, components and operations referred to as "including" do not exclude the presence or addition of one or more other components and operations.

[0025] Unless otherwise specified, all terms (including technical and scientific terms) used in this specification are used in the sense commonly understood by those having ordinary knowledge in the technical field to which the present invention belongs. Furthermore, terms defined in a commonly used dictionary should not be interpreted ideally or excessively unless otherwise specified. Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings.

[0026] As shown in Figs. 1, 2A, 2B and 2C, a typical gas-insulated switchgear 100 includes a housing 10 forming a case, a busbar section 20 provided in the upper part of the inside of the housing 10 and consisting of a main busbar 21 for connecting a service line through which a large current flows and a supporting insulator supporting the main busbar, a three-terminal switch section 30 partitioned by an insulating bulkhead spacer 80 located on the upper part of the inside of the housing 10 and consisting of a fixed electrode 31 connected to the main busbar 21, a grounding electrode 33 connected to the ground, and a movable electrode 35 selectively connected to the fixed electrode 31 and the three-terminal switch section 30 which plays two roles: a disconnect switch (DS) which enables separation and connection of lines in a voltage-free state, and an earth switch (ES) which is used for earth switching operation for maintenance and inspection, a circuit breaker section 40 partitioned in the center of the inside of the housing 10 to protect load equipment and lines from large fault currents such as short circuits and ground faults that occur in the circuit, a cable connection section 50 to which a distribution line is connected, and a control panel 60 for operating, controlling, measuring and monitoring the gas-insulated switchgear.

[0027] All electrically live conductors located within the sealed housing 10 of the gas-insulated switchgear 100 are electrically insulated by the insulating gas 70 filled therein, and each component is separated into gas compartments by insulating partition spacers 80, so that the transfer of an accident in one component to other components is minimized. The metal housing 10 is connected to an external ground to maintain an electrically grounded state, and is configured to ensure the safety of operators during inspection and maintenance of the switchgear.

[0028] The circuit breaker section 40 of the gas-insulated switchgear 100 is formed as a compartment within the housing 10 of the gas-insulated switchgear 100 filled with insulating gas 70, and is interposed between the three-terminal switchgear section 30 and the cable connection section 50 to protect the load equipment and the line from fault currents. Circuit breakers are classified as vacuum circuit breakers, gas circuit breakers, etc. depending on the arc-extinguishing medium for the arc generated during opening and closing. Generally, for transmission voltage classes (154 kV class or higher), gas circuit breakers that use SF6 gas as an arc-extinguishing medium are mainly used, and for distribution voltage classes with rated voltages lower than that, vacuum interrupters with excellent arc-extinguishing and insulation performance are mainly used.

[0029] As shown in FIG. 2C , in the case of circuit breaker section 40 of the gas-insulated switchgear composed of a vacuum interrupter, fixed electrode section 142 and movable electrode section 143 are arranged coaxially in cylindrical ceramic insulating tube 141, the interior of which is sealed by a vacuum, and a shielding plate 145 is attached to the inner wall of ceramic insulating tube 141 to prevent metallic ions released due to arc generation caused by switching operation of the contacts from adhering to the inner wall of ceramic insulating tube 141 and deteriorating the insulating performance.

[0030] The circuit breaker section 40 constituted by the solid insulated switchgear shown in FIG. 3 mainly includes components such as an epoxy insulator housing 127 molded from a polymer, a vacuum valve 122 attached by molding inside the polymer epoxy insulator housing 127, an insulating rod 126 connecting the vacuum interrupter to an operating device (not shown), a primary conductor 121 for electrical connection with the power source side, a secondary conductor 120 for electrical connection and coupling with the load side, a wound type current transformer 125 for measuring the load current, and a primary voltage detection sensor 123 and a secondary voltage detection sensor 124 for voltage detection. The opening and closing operation of the solid insulated switchgear is performed by manual operation using a manual operating handle or by electrical operation using an electric motor. The clockwise or counterclockwise rotational power generated by the electrical or manual operation is transmitted to a power transmission device (not shown) via a drive shaft (not shown). The power transmission device converts the clockwise or counterclockwise rotational power into a vertical opening and closing drive force and transmits it to the insulating rod 246, thereby driving the lower main contact of the switch to perform the opening and closing operation.

[0031] Since power systems are configured with three-phase AC to efficiently supply electrical energy, all electrical equipment used in the system, such as switchgear and general switches, are configured in three-phase form. Generally, power switches used in power systems perform switching operations by operating movable electrodes 35 for all three phases at once with one operating device on an external control panel. The main elements of operating characteristics for performance evaluation of power switches are the switching time of each phase of the power switch, the non-simultaneous switching time of three poles, the stroke, operating speed, etc.

[0032] When a power switchgear is opened or closed on-site or remotely by communication means, it must complete the opening / closing operation within the specified opening / closing time when a switching operation signal is given, and must not exceed the three-pole non-simultaneous opening / closing time specified in the standard. The three-pole non-simultaneous opening / closing time of a power switchgear refers to the difference in operation time of each phase of the power switchgear that occurs when operating the three phases together due to the link length of each phase, assembly tolerances that occur when assembling components of mechanical operators such as levers, shafts, and rods, and electrical and mechanical defects during operation. If the difference in opening / closing time between each phase is large, the power switchgear may become unable to open or close (shut off), so continuous real-time status monitoring and diagnosis are required.

[0033] During development testing before application to the power grid, power switchgears are verified in advance by determining upper and lower limits for the size of the control power source and measuring operating characteristics such as the opening and closing time for each phase, the non-simultaneous opening and closing time for three poles, stroke, and operating speed. However, since they will continue to be used after application to the power grid, it is difficult to diagnose operating characteristics caused by electrical and mechanical defects that occur during operation. As a complementary measure, Korea Electric Power Corporation currently maintains power switchgears by measuring operating characteristics when operation is stopped and no voltage is applied on short, medium, and long-term inspection schedules in accordance with its operating guidelines.

[0034] When the main contacts of a power switch become worn out due to long-term use, the insulation performance of the switch decreases and the operating characteristics change, and the increase in main circuit resistance increases heat generation from the live conductor, adversely affecting the basic physical and chemical characteristics of the surrounding insulators. In addition, if the pressure between the contacts is insufficient and the electrodes are separated from their normal positions due to the electromagnetic force generated when a large current flows, it can lead to a major electrical accident. Therefore, there is a demand for the application of technology that can monitor and diagnose the operating characteristics of the power switch when opening and closing in real time, not only during inspections when the power is off, but also during operation when voltage is applied.

[0035] As shown in FIG. 4, the power switch operating characteristic monitoring system according to the present invention measures and calculates operating characteristics such as the opening and closing time of each phase of the power switch, the three-pole non-simultaneous opening and closing time, stroke, operating speed, etc. in real time during pressurized operation, and if the measured values ​​deviate from a predetermined safety range, a control signal for an alarm or locking is output, so that an alarm sound is outputted to the outside by the alarm means so that the manager can take appropriate measures, or the operation of the power switch is automatically stopped by the locking means, thereby preventing serious accidents caused by electrical or mechanical abnormalities in the power switch.

[0036] The capacitance-type electrode sensor unit for the power switch operating characteristic monitoring system is installed in the power switch in the form of an electrode sensor structure including an electrode impregnated inside the insulator of the insulating partition spacer 80 of the switch, or is installed outside the insulating partition spacer in the form of an electrode sensor module having a structural feature that allows it to be detached and attached, and is electrically composed of a composite circuit of capacitances C1, C2 that are formed sequentially between the main conductor and electrode sensor of the power switch and between the electrode sensor and the housing. When the movable electrode 35 changes position spatially in response to a control command, the voltage induced by the capacitance-type electrode sensor changes, and by using this characteristic, it is possible to monitor in real time changes in the state of operating characteristics of the power switch during operation, such as the opening and closing time of each phase, the three-pole non-simultaneous opening and closing time, stroke, operating speed, etc.

[0037] As shown in Figures 5A, 5B, and 5C, internal electrode sensors that are impregnated inside an insulator to monitor and diagnose the operating characteristics of a power switchgear are configured in various forms depending on the type and structure of the power switchgear.

[0038] As shown in Fig. 5A, in a system for monitoring operational characteristics of electric power switches such as phase-separated gas-insulated switchgear, a three-terminal switch electrode sensor is installed for each phase inside a single-phase insulating partition spacer 80 between the three-terminal switch section 30 and the circuit breaker section 40 in the form of an annular or rectangular conductor, and a circuit breaker electrode sensor is installed for each phase inside a single-phase insulating partition spacer 80 between the circuit breaker section 40 and the cable connection section 50 in the form of an annular or rectangular conductor. As shown in Fig. 5B, in a system for monitoring operational characteristics of electric power switches such as three-phase integrated gas-insulated switchgear, the electrode sensors are arranged in a structure in which three annular or rectangular conductors are collectively configured inside one three-phase insulating partition spacer 80 between the three-terminal switch section 30 and the circuit breaker section 40 and between the circuit breaker section 40 and the cable connection section 50. As shown in FIG. 5C, in a system for monitoring the operational characteristics of a power switch such as a solid insulated switchgear, an electrode sensor is installed in the form of a ring-shaped or rectangular conductor inside an external epoxy insulator housing 127 that impregnates the switching section (vacuum interrupter and blade-type contacts) that is electrically connected to the primary inlet 121 of the switch.

[0039] In a system for monitoring the operating characteristics of electric power switches, such as a phase separation type gas insulated switchgear, one of the embedded metal fittings (nut type) of a conventional insulating partition spacer 80 may be insulated and used directly as a capacitance type electrode sensor, as shown in Fig. 6A, or one pin type electrode that is impregnated and insulated may be added between the embedded metal fittings (nut type) of the insulating partition spacer and used as a capacitance type electrode sensor, as shown in Fig. 6B. Similarly, in a system for monitoring the operating characteristics of electric power switches, such as a three-phase integrated gas insulated switchgear, three of the embedded metal fittings (nut type) of the insulating partition spacer adjacent to the main conductor of each phase may be insulated and used directly as a capacitance type electrode sensor for each phase, or three pin type electrodes that are impregnated and insulated may be added between the embedded metal fittings (nut type) of the insulating partition spacer and used as a capacitance type electrode sensor for each phase.

[0040] As shown in Figures 7A and 7B, the detachable electrode sensor module unit for monitoring and diagnosing the operating characteristics of a power switchgear has electrode sensors for each phase installed in a ring structure that can be detached and attached to the outside of an insulating partition spacer without changing the structure of the power switchgear, and therefore has a structural feature that it can be easily installed and applied as an add-on not only to newly applied switchgears but also to existing switchgears.

[0041] The power switch operation characteristic monitoring system according to the present invention includes a voltage detection capacitance-type electrode sensor and electrode sensor module, which are configured in various forms according to the type of power switch, and a monitoring means that is connected to each of the electrode sensors and converts and calculates signals input from the electrode sensors into digital signals to simultaneously calculate, diagnose and display the opening and closing time, three-pole non-simultaneous opening and closing time, stroke and operating speed of each phase of the power switch, and outputs a control signal for an alarm or locking if the calculated output value deviates from a predetermined operating characteristic limit range. Therefore, it is possible to replace and maintain the power switch at an appropriate time, and to prevent accidents in the power system and power equipment in advance and ensure the operational reliability of the system.

[0042] 8A, 8B, and 8C are diagrams showing potential distribution diagrams of the three-terminal switch part of a gas-insulated switchgear by the finite element method, and induced voltages of an electrode sensor according to the present invention, when the three-terminal switch of the gas-insulated switchgear is in an open state (DS / ES Open) (FIG. 8A), when the disconnector is in a closed state (DS Close) (FIG. 8B), and when the earthing switch is in a closed state (ES Close) (FIG. 8C). It is confirmed that the voltages induced by the capacitance-type electrode sensor are different depending on the spatial position change of the movable electrode due to the operation of the switch. The induced voltage when the three-terminal switch is in an open state is defined as V OPEN The induced voltage when the disconnector is closed is V DSCL The induced voltage when the earthing switch is closed is V ESCL Then, as shown in the figure, V DSCL =19.03%[V], V OPEN =3.44%[V], V ESCL=0.00%[V]. V DSCL , V OPEN , V ESCL The respective values ​​of V are illustrative and are not necessarily limited to these. DSCL >V OPEN >V ESCL It has been confirmed that the opening and closing time of a three-terminal switch can be measured from the change in induced voltage of the electrode sensor that occurs in response to the change in internal capacitance caused by the positional movement of the movable electrode.

[0043] FIG. 9A is a diagram showing the basic concept of measuring the opening and closing times of each phase using changes in induced voltage of a capacitance-type electrode sensor that appear when the three-terminal switch unit of the gas-insulated switchgear according to the present invention performs the disconnector closing, disconnector opening, and earth switch closing operations. FIG. 9B is a diagram showing the measurement concept of three-pole non-simultaneous opening and closing times during closing operation and three-pole non-simultaneous opening and closing times during opening operation by the operation of the three-terminal switch unit of the gas-insulated switchgear.

[0044] When the three-terminal switch of the gas-insulated switchgear is in an open (DS / ES Open) state, if a disconnector close command is transmitted by the control switch, the motor for the operating device is driven, and a force is transmitted to the movable electrode 35 via an external link connected to each other, and the movable electrode of the power switch moves from the open position to the disconnector close position. Here, the operating current of the motor for the operating device of the power switch changes until the operation of the movable electrode 35 is completed, as shown in FIG. 9A. When the position of the movable electrode changes, the values ​​of the capacitance C1 between the pressurized busbar 21 and the electrode sensor, and the capacitance C2 between the electrode sensor and the grounded housing change, and the voltage induced in the electrode sensor is the voltage V of the electrode sensor in the open position. OPEN When the disconnector closing operation is completed, the voltage induced in the electrode sensor reaches a voltage value V DSCL When the power switch in the disconnector closed position receives a disconnector open command, it goes through the same electrical and mechanical operation process. Here, the voltage induced in the electrode sensor is the opposite to when the disconnector is closed, and converges to a constant V DSCL Value to V OPENThe voltage V changes in a manner that decreases from V to V, and finally converges to a constant value. The closing and opening operations of the earthing switch are also carried out through the same process as described above, but the induced voltage of the electrode sensor during the closing operation of the earthing switch is V OPEN From V ESCL (=0V), and the induced voltage when the earthing switch is opened is V ESCL From V OPEN The trend is for the price to rise.

[0045] As shown in Fig. 9A, the operation characteristic monitoring system for three-terminal switches of gas-insulated switchgear, which is an application example of the present invention, can measure the switching time of each phase in real time during pressurized operation from changes in induced voltage of electrode sensors installed in each phase, and can also calculate and diagnose the three-pole non-simultaneous switching time during switching operation of the three-terminal switch by comparing and analyzing the switching time difference of each phase as shown in Fig. 9B. The three-terminal switch operation characteristic monitoring system according to the present invention constantly monitors and diagnoses electrical and mechanical abnormalities of the three-terminal switch of the power switch by comparing the operation characteristic data collected in real time with reference operation characteristic data in a normal state, so that preemptive maintenance measures can be taken.

[0046] 10A and 10B are diagrams showing a potential distribution diagram of a circuit breaker part of a gas-insulated switchgear using a vacuum interrupter and an induced voltage of an electrode sensor according to the present invention by the finite element method. It is confirmed that, in the circuit breaker closed (CB Close) and open (CB Open) states of the gas-insulated switchgear, the voltage induced by the capacitance-type electrode sensor in response to the spatial position change of the movable electrode 35 due to the circuit breaker operation is higher in the circuit breaker closed position (19.19% [V]) than in the open position (2.46% [V]). The induced voltage of the electrode sensor in the circuit breaker closed position (19.19% [V]) and the induced voltage in the open position (2.46% [V]) are illustrative values ​​and are not necessarily limited to these, but as with the application to the three-terminal switch section of a gas-insulated switchgear, the opening and closing time of each phase and the three-pole non-simultaneous opening and closing time during the opening and closing operation of the circuit breaker can be measured from the change in induced voltage of the electrode sensor, and real-time online measurement and diagnosis of the stroke and operating speed are also possible.

[0047] FIG. 11A is a diagram showing a change in induced voltage of a capacitance-type electrode sensor when the gap between the fixed contact and the movable contact changes by 1 mm when the circuit breaker of the gas-insulated switchgear according to the present invention operates from a closed circuit state to an open circuit state.

[0048] Fig. 11B is a diagram showing the concept of measuring the operating stroke of a circuit breaker based on the change in induced voltage of the electrode sensor in Fig. 11A, and is a diagram estimated by considering the electrical and mechanical characteristics of the operating device according to the time change when the circuit breaker of the gas-insulated switchgear receives an operating command and completes the opening and closing operation. In a circuit breaker using a spring charging type operating device, which is mainly used in the Korean distribution voltage class, when a control power is supplied, the closing spring is compressed by a cam and a crank connected to the motor, and when a closing command is given, the closing coil is excited to operate the closing coil, releasing the compression of the closing spring, and the operating shaft is rotated by the operation of a roller connected to the operating shaft to perform a quick closing operation, and during the closing operation, the opening spring is compressed at the same time, and after the operation, the pressure contact force of the circuit breaker contact is maintained by a wipe spring mechanically connected to the operating shaft. In the opening operation, when an opening command is given, the rod is operated by the excitation of the opening coil, and the operating shaft rotates by the restoring force of the opening spring and the wipe spring, and the circuit breaker performs the opening operation very quickly in a short time. As shown in the stroke curve of Fig. 11B, there is a time delay when the coil is excited to perform the opening and closing operation, and a time required for the process of transmitting the force of the cam, lever, shaft, rod, etc. that constitute the operating device, so a time delay phenomenon occurs in the transmission of force at the beginning of the opening and closing operation, and mechanical vibration occurs during the opening and closing operation due to the influence of various springs used in the mechanical operating device and the contact repulsion force, etc., and the contact gap fluctuates, so the stroke curve using the induced voltage also shows an oscillating aspect. Based on the circuit breaker contact gap that has already been input in advance, the opening and closing average speed and initial speed of the circuit breaker of the gas-insulated switchgear can be monitored, diagnosed, and displayed in real time by utilizing the digital data of the opening and closing time and stroke curve of each phase obtained as described above.

[0049] According to the above method, the operational characteristic monitoring system for power switches according to the present invention can be expanded and applied to all power switches that use a method of opening and closing by a structure in which contacts are separated and moved, such as switchgear and general switches such as circuit breakers, load switches, automatic transfer switches, automatic fault section switches, automatic load transfer switches, and disconnectors.

[0050] As shown in FIG. 12 , the integrated monitoring means 200 includes an input conversion unit 230 that converts a signal input from a secondary side reference voltage of a potential transformer (PT) and a voltage detection capacitance type electrode sensor into a voltage value, an A / D converter 240 that converts the voltage value received from the input conversion unit 230 into a digital signal, a central arithmetic and control unit 250 that is connected to the A / D converter 240 and calculates and diagnoses operating characteristics such as the opening and closing time of each phase of the power switchgear, the three-pole non-simultaneous opening and closing time, stroke, operating speed, etc., based on the digital signal input via the A / D converter 240, and a central arithmetic and control unit 250 that is connected to the central arithmetic and control unit 250. The system includes a control signal generating unit 260 which outputs a control signal for an alarm or locking when the operating characteristic value of the power switch diagnosed by the central computing and control unit 250 deviates from a predetermined safety range, a display unit 270 which is connected to the central computing and control unit 250 and digitally displays the open / closed state of each power switch calculated and diagnosed by the central computing and control unit 250, a key input unit 280 which is connected to the central computing and control unit 250 and enables setting of an operation mode or a safety range, and a power supply unit 290 which supplies power required for operation from an external power source 400.

[0051] An A / D converter 240 is connected to the input conversion unit 230, and the A / D converter 240 converts the voltage value received from the input conversion unit 230 into a digital signal and transmits it to a central processing unit 250 which functions as a digital processing device.

[0052] The central processing unit 250 connected to the A / D converter 240 calculates and diagnoses the operating characteristic values ​​of the power switch of each phase based on the digital signal input via the A / D converter 240, and transmits the calculated operating characteristic values ​​to the display unit 270. If the calculated operating characteristic value deviates from a predetermined safe range, the central processing unit supplies the corresponding signal to the control signal generating unit 260, and presets an operating mode or a safe operating characteristic value range in response to an input signal input from the key input unit 280. The central processing unit 250 is formed in the form of a printed circuit board on which a predetermined circuit is printed, or a chip on which a predetermined circuit is integrated.

[0053] The control signal generating unit 260 connected to the central computing and control unit 250 outputs a control signal for an alarm or locking when an operating characteristic value calculated and diagnosed by the central computing and control unit 250 deviates from a predetermined safety range due to an electrical or mechanical defect, so that an alarm sound is output to the outside using a predetermined alarm means (not shown) connected to the control signal generating unit 260 so that an administrator can take appropriate measures, or the operation of the power switch is automatically cut off using a predetermined locking means (not shown) connected to the control signal generating unit 260.

[0054] The control signal generating unit 260 is installed on the rear surface of the integrated monitoring means 200 and includes a control signal output terminal for outputting a control signal for an alarm or locking, and the above-mentioned alarm means and locking means are electrically connected to the control signal output terminal.

[0055] The display unit 270 connected to the central computing control unit 250 digitally displays the operating characteristic values ​​of the power switch of each phase calculated and diagnosed by the central computing control unit 250, and includes a panel that displays operating characteristics such as the opening and closing time of each phase of the power switch, the three-pole non-simultaneous opening and closing time, stroke, operating speed, etc., in digital values ​​and graphs, a safety range display window that continuously displays the safety range and the upper and lower danger ranges, and two operation display lamps (not shown) installed on the front side of the integrated monitoring means 200 and that respectively display whether or not the control signal generating unit 260 outputs a control signal for an alarm or locking, but are not necessarily limited thereto.

[0056] The key input unit 280 connected to the central processing unit 250 enables the setting of the operation mode, the range of safe operating characteristic values, etc., and includes a mode selection button that enables the setting of the operation mode, and a safety range setting button that enables the setting of the range of safe operating characteristic values, but is not necessarily limited to these.

[0057] The power supply unit 290 supplies power required for operation from an external power supply 400, and includes a power connection terminal (not shown) to which the external power supply 400 is connected, as shown in Fig. 8. The external power supply 400 is preferably a DC voltage for stable operation of the integrated monitoring means 200.

[0058] The communication module 265 connected to the central processing unit 250 enables communication with a remote external computer and allows the remote external computer to monitor the operating characteristics of the power switch, and is preferably configured as a known wired communication module such as a modem or a known wireless communication module such as Bluetooth.

[0059] In addition, the integrated monitoring means 200 may further include a filter unit 210 sequentially connected between the input conversion unit 230 and the A / D converter 240, which removes noise from the voltage value output from the input conversion unit 230, and a linear processing unit 220 which linearizes the voltage value passing through the filter unit 210 and supplies it to the A / D converter 240.

[0060] Since abnormal voltages may be present inside a power switchgear that is operated with a high voltage applied thereto due to magnetic fields and switching surges, a filter unit 210 is provided to remove such abnormal voltages, and it is preferable that the filter unit 210 is configured with a low pass filter.

Claims

1. In the power switch, a capacitance type electrode sensor is installed outside a primary side conductor and detects an electrostatic voltage induced when a main contact of the power switch is opened and closed; and an integrated monitoring means for diagnosing the operating characteristics of each phase based on the electrostatic voltage input from the capacitive electrode sensor, and outputting a control signal for an alarm or locking when a predetermined operating characteristic safety range is exceeded. An operational characteristic monitoring system for power switchgear.

2. When the main contact of the power switch performs an opening and closing operation, the voltage induced in the electrode sensor changes according to a voltage division characteristic caused by a fluctuation in the relative internal capacitance of the electrode sensor of the power switch. The power switchgear operational characteristic monitoring system according to claim 1 .

3. The capacitance type electrode sensor is characterized in that it is composed of a composite circuit of capacitances (C1, C2) electrically formed sequentially between the primary conductor and the electrode sensor, and between the electrode sensor and the ground electrode. The power switchgear operational characteristic monitoring system according to claim 1 .

4. The capacitive electrode sensor is a non-contact type, The electrode sensor is in the form of a circular, square or pin-shaped electrode sensor impregnated in the insulator in the internal space of the insulating partition spacer between the breaker unit and the three-terminal switch unit, and between the three-terminal switch unit and the busbar unit. The circuit breaker is made up of circular, square and pin-shaped electrode sensors inside and outside the epoxy insulator housing. The insulating partition spacer and the insulator are configured in the form of a detachable electrode sensor module outside the insulating partition spacer and the insulator. The power switchgear operational characteristic monitoring system according to claim 1 .

5. The operating characteristics diagnosed based on the capacitance type electrode sensor include a switching time of each phase of the power switch, a three-pole non-simultaneous switching time, a stroke, and an operating speed. The power switchgear operational characteristic monitoring system according to claim 1 .

6. The integrated monitoring means receives operation and control signals including a secondary voltage of a potential transformer (PT), a control power supply, a coil current, a motor current, and an auxiliary contact signal of a power switch from an operation control panel. The power switchgear operational characteristic monitoring system according to claim 1 .

7. The integrated monitoring means comprises: an input conversion unit that converts signals input from a potential transformer (PT) and an electrode sensor into voltage values; an A / D converter connected to the input conversion unit and configured to convert a voltage value received from the input conversion unit into a digital signal; a central processing unit connected to the A / D converter and configured to diagnose an opening / closing operation of a switching device for each phase based on a digital signal input via the A / D converter; a control signal generating unit connected to the central processing unit and configured to output a control signal for issuing an alarm or locking when an open / close state of the switching device diagnosed by the central processing unit deviates from a predetermined safety range; a display unit connected to the central processing unit and digitally displaying the open / closed state of the switching device diagnosed by the central processing unit; a key input unit connected to the central arithmetic and control unit for setting an operation mode or a safe vacuum range; and a power supply unit provided within the integrated monitoring means for supplying power required for the operation of the integrated monitoring means from an external power source. The power switchgear operational characteristic monitoring system according to claim 1 .

8. The integrated monitoring means comprises: The power switch further includes a communication module connected to the central processing unit, which enables communication with a remote external computer and enables the remote external computer to monitor operating characteristics of the power switch, including the switching time of each phase, the three-pole non-simultaneous switching time, the stroke, and the operating speed. The power switchgear operational characteristic monitoring system according to claim 7.

9. The power switch includes a gas insulated switchgear, a solid insulated switchgear, a circuit breaker, a load switchgear, an automatic transfer switch, an automatic fault section switchgear, an automatic load transfer switchgear, a grounding switchgear, and a disconnector, each of which has a switching method using contacts. The power switchgear operational characteristic monitoring system according to claim 1 .

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