Monitoring system for closing coil and opening coil of circuit breaker

Abstract

The invention discloses a monitoring system for a closing coil and an opening coil of a circuit breaker, and relates to the technical field of circuit equipment monitoring. The system comprises a monitoring controller, a circuit breaker coil monitoring circuit, a closing coil monitoring circuit and an opening coil monitoring circuit. The monitoring controller can obtain a positive bus-to-ground DC voltage, a negative bus-to-ground DC voltage, a first current value flowing into the closing coil and a second current value flowing into the opening coil from the circuit breaker coil monitoring circuit, the closing coil monitoring circuit and the opening coil monitoring circuit. And determining whether the closing coil of the circuit breaker is broken based on the positive bus-to-ground DC voltage, the negative bus-to-ground DC voltage and the first current value, and determining whether the opening coil of the circuit breaker is broken based on the positive bus-to-ground DC voltage, the negative bus-to-ground DC voltage and the second current value. According to the system, the circuit break monitoring accuracy of the closing coil and the opening coil of the circuit breaker can be remarkably enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit equipment monitoring, and in particular to a monitoring system for a closing coil and an opening coil of a circuit breaker. Background Art

[0002] As the society's demand for electricity consumption increases, people's requirements for the stability of power grid operation are also increasing. At present, defects in relay protection circuits are one of the main causes of power grid failures. Among them, incorrect protection caused by the circuit breaker's closing coil and opening coil breaking is the main cause of relay protection circuit defects. Therefore, it is necessary to monitor the circuit breaker's closing coil and opening coil to detect whether the circuit breaker's closing coil and opening coil are broken in advance, and then take corresponding measures to ensure the normal operation of the power grid.

[0003] Currently, the existing method for monitoring the closing coil and opening coil of the circuit breaker is easily affected by the busbar-to-ground voltage of the busbar where the circuit breaker is located. When the busbar-to-ground voltage is undervoltage, it is easy to mistakenly believe that the closing coil or the opening coil is open-circuited, resulting in low accuracy in the open-circuit monitoring of the closing coil and the opening coil of the circuit breaker. Summary of the invention

[0004] In view of this, the present application provides a monitoring system for the closing coil and the opening coil of a circuit breaker, the main purpose of which is to solve the technical problem of low circuit breaker monitoring accuracy in the existing method for monitoring the closing coil and the opening coil of a circuit breaker.

[0005] According to a first aspect of the present invention, a monitoring system for a closing coil and an opening coil of a circuit breaker is provided, which is used to monitor the closing coil and the opening coil of the circuit breaker for disconnection. The monitoring system for the closing coil and the opening coil of the circuit breaker comprises a monitoring controller, a circuit breaker coil monitoring circuit, a closing coil monitoring circuit and an opening coil monitoring circuit;

[0006] The circuit breaker coil monitoring circuit is arranged between the positive bus and the negative bus where the circuit breaker is located, and is used to collect the DC voltage of the positive bus to the ground and the DC voltage of the negative bus to the ground;

[0007] The closing coil monitoring circuit is connected between the positive busbar and the positive terminal of the closing coil of the circuit breaker, and is used to collect a first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil; the opening coil monitoring circuit is connected between the positive busbar and the positive terminal of the opening coil of the circuit breaker, and is used to collect a second current value flowing from the opening coil monitoring circuit to the positive terminal of the opening coil;

[0008] The monitoring controller is used to determine whether the positive bus and the negative bus are undervoltage based on the positive bus-to-ground DC voltage and the negative bus-to-ground DC voltage, and when the positive bus and the negative bus are not undervoltage, determine whether the closing coil is open-circuited based on the first current value, and determine whether the opening coil is open-circuited based on the second current value.

[0009] In an optional embodiment, the monitoring controller is used to determine whether the positive bus and the negative bus are undervoltage based on the positive bus DC voltage to ground and the negative bus DC voltage to ground, including: determining whether the sum of the positive bus DC voltage to ground and the negative bus DC voltage to ground is greater than a preset DC voltage threshold; if the sum of the positive bus DC voltage to ground and the negative bus DC voltage to ground is greater than the preset DC voltage threshold, determining that the positive bus and the negative bus are not undervoltage.

[0010] In an optional embodiment, the circuit breaker coil monitoring circuit includes a first voltage-dividing resistor, a second voltage-dividing resistor, a first voltage collector and a second voltage collector; the first voltage-dividing resistor and the second voltage-dividing resistor are connected in series between the positive bus and the negative bus, and the first voltage-dividing resistor and the second voltage-dividing resistor are grounded; the first voltage collector is used to collect a first voltage drop across the first voltage-dividing resistor, and send the first voltage drop as the positive bus-to-ground DC voltage to the monitoring controller; the second voltage collector is used to collect a second voltage drop across the second voltage-dividing resistor, and send the second voltage drop as the negative bus-to-ground DC voltage to the monitoring controller.

[0011] In an optional embodiment, the monitoring controller is used to determine whether the positive bus and the negative bus are undervoltage based on the positive bus DC voltage to ground and the negative bus DC voltage to ground, including: the monitoring controller determines whether the sum of the positive bus DC voltage to ground and the negative bus DC voltage to ground is greater than a preset DC voltage threshold; if the sum of the positive bus DC voltage to ground and the negative bus DC voltage to ground is greater than the preset DC voltage threshold, it is determined that the positive bus and the negative bus are not undervoltage.

[0012] In an optional embodiment, the monitoring controller determines whether the closing coil is open circuit based on the first current value, including: the monitoring controller determines whether the first current value flowing from the closing coil monitoring circuit to the positive end of the closing coil is less than a first preset current threshold; if the first current value is less than the first preset current threshold, it is determined that the closing coil is open circuit.

[0013] In an optional embodiment, the closing coil monitoring circuit includes a first current sampling circuit, a first current sensor and a first optical coupling circuit breaker; the first end of the first current sampling circuit is connected to the positive bus, the second end of the first current sampling circuit is connected to the first end of the normally open auxiliary contact of the circuit breaker, and the second end of the normally open auxiliary contact is connected to the positive end of the closing coil; the first optical coupling circuit breaker contact of the first optical coupling circuit breaker is connected in parallel with the normally open auxiliary contact; the first control end of the monitoring controller is connected to the controlled end of the first optical coupling circuit breaker, and is used to control the first optical coupling circuit breaker contact to be turned on or off; the first current sensor is used to collect a first current value of the current flowing through the first current sampling circuit, and send the first current value to the monitoring controller. The monitoring controller determines whether the first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil is less than the first preset current threshold, including: the monitoring controller obtains the first current value from the first current sensor, and determines whether the first current value is less than the first preset current threshold; if the first current value is less than the first preset current threshold, the first optical coupling circuit breaker contact is controlled to be turned on, and after a preset time period, the first current value is obtained from the first current sensor again, and it is determined whether the first current value is still less than the first preset current threshold; if the first current value is still less than the first preset current threshold, it is determined that the first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil is less than the first preset current threshold.

[0014] In an optional embodiment, the monitoring controller determines whether the opening coil is open circuit based on the second current value, including: the monitoring controller determines whether the second current value flowing from the opening coil monitoring circuit to the positive end of the opening coil is less than a second preset current threshold; if the second current value is less than the second preset current threshold, it is determined that the opening coil is open circuit.

[0015] In an optional embodiment, the opening coil monitoring circuit includes a second current sampling circuit, a second current sensor and a second optically coupled circuit breaker; the first end of the second current sampling circuit is connected to the positive bus, the second end of the second current sampling circuit is connected to the first end of the normally closed auxiliary contact of the circuit breaker, and the second end of the normally closed auxiliary contact is connected to the positive end of the opening coil; the second optically coupled circuit breaker contact of the second optically coupled circuit breaker is connected in parallel with the normally closed auxiliary contact; the second control end of the monitoring controller is connected to the controlled end of the second optically coupled circuit breaker, and is used to control the second optically coupled circuit breaker contact to be turned on or off; the second current sensor is used to collect a second current value of the current flowing through the second current sampling circuit, and send the second current value to the monitoring controller. Controller; the monitoring controller determines whether the second current value flowing from the opening coil monitoring circuit to the positive terminal of the opening coil is less than the second preset current threshold, including: the monitoring controller obtains the second current value from the second current sensor, and determines whether the second current value is less than the second preset current threshold; if the second current value is less than the second preset current threshold, the second photocoupler circuit breaker contact is turned on, and after a preset time period, the second current value is obtained from the second current sensor again, and it is determined whether the second current value is still less than the second preset current threshold; if the second current value is still less than the second preset current threshold, it is determined that the second current value flowing from the opening coil monitoring circuit to the positive terminal of the opening coil is less than the second preset current threshold.

[0016] In an optional embodiment, the first voltage collector is also used to collect the first AC voltage value of the first voltage-dividing resistor, and the second voltage collector is also used to collect the second AC voltage value of the second voltage-dividing resistor; the monitoring controller is also used to determine whether the first AC voltage value and the second AC voltage value are greater than a preset AC voltage threshold. If the first AC voltage value or the second AC voltage value is greater than the preset AC voltage threshold, it is determined that AC inrush exists in the positive bus and the negative bus.

[0017] In an optional embodiment, the first current sampling circuit includes a first current limiting resistor and a first current measuring resistor; the first end of the first current limiting resistor is connected to the positive bus, the second end of the first current limiting resistor is connected to the first end of the first current measuring resistor, and the second end of the first current measuring resistor is connected to the first end of the normally open auxiliary contact; the first current sensor includes a first voltage drop sensor, a first conditioning circuit and a first current collector; the first voltage drop sensor is used to collect the first DC voltage drop value across the first current measuring resistor and send the first DC voltage drop value to the first conditioning circuit; the first conditioning circuit is used to perform signal amplification processing on the first DC voltage drop value to obtain a first conditioned voltage drop value, and send the first conditioned voltage drop value to the first current collector; the first current collector is used to obtain the first conditioned voltage drop value, perform analog-to-digital conversion processing on the first conditioned voltage drop value, and determine the first current value based on the first conditioned voltage drop value after the analog-to-digital conversion processing.

[0018] In an optional embodiment, the second current sampling circuit includes a second current limiting resistor and a second current measuring resistor; the first end of the second current limiting resistor is connected to the positive bus, the second end of the second current limiting resistor is connected to the first end of the second current measuring resistor, and the second end of the second current measuring resistor is connected to the first end of the normally closed auxiliary contact; the second current sensor includes a second voltage drop sensor, a second conditioning circuit and a second current collector; the second voltage drop sensor is used to collect the second voltage drop value across the second current measuring resistor and send the second voltage drop value to the second conditioning circuit; the second conditioning circuit is used to perform signal amplification processing on the second voltage drop value to obtain a second conditioned voltage drop value, and send the second conditioned voltage drop value to the second current collector; the second current collector is used to obtain the second conditioned voltage drop value, perform analog-to-digital conversion processing on the second conditioned voltage drop value, and determine the second current value based on the second conditioned voltage drop value after the analog-to-digital conversion processing.

[0019] The present invention provides a monitoring system for the closing coil and the opening coil of a circuit breaker. First, the positive bus and the negative bus where the circuit breaker is located are determined to be undervoltage through the positive bus-to-ground DC voltage of the positive bus and the negative bus-to-ground DC voltage of the negative bus. Then, when the positive bus and the negative bus are not undervoltage, it is determined whether the closing coil is open-circuited based on the first current value flowing from the closing coil monitoring circuit to the positive end of the closing coil, and it is determined whether the opening coil is open-circuited based on the second current value flowing from the opening coil monitoring circuit to the positive end of the opening coil. It is possible to comprehensively analyze whether the closing coil and the opening coil have open-circuit problems while considering the bus-to-ground voltage of the bus, thereby enhancing the accuracy of the open-circuit monitoring of the closing coil and the opening coil of the circuit breaker.

[0020] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 A schematic structural diagram of a monitoring system for a closing coil and an opening coil of a circuit breaker provided by an embodiment of the present invention is shown;

[0023] Figure 2a A schematic structural diagram of a closing coil monitoring circuit provided by an embodiment of the present invention is shown;

[0024] Figure 2b A schematic structural diagram of a first current sensor provided by an embodiment of the present invention is shown;

[0025] Figure 3a A schematic structural diagram of a trip coil monitoring circuit provided by an embodiment of the present invention is shown;

[0026] Figure 3b A schematic structural diagram of a second current sensor provided by an embodiment of the present invention is shown;

[0027] Figure 4 A schematic structural diagram of a circuit breaker coil monitoring circuit provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0029] In one embodiment, Figure 1 As shown, a monitoring system for closing coil and opening coil of a circuit breaker is provided, which is used to monitor the breaking of closing coil and opening coil of the circuit breaker, and the monitoring system for closing coil and opening coil of the circuit breaker includes a monitoring controller, a circuit breaker coil monitoring circuit, a closing coil monitoring circuit and an opening coil monitoring circuit. Here, the monitoring controller can be connected to a remote host computer to send an alarm message to the remote host computer. The host computer can be a remote control terminal or other equipment, and the relevant staff can view the alarm message sent by the monitoring controller from the host computer.

[0030] Specifically, the circuit breaker coil monitoring circuit is arranged between the positive bus and the negative bus where the circuit breaker is located, and is used to collect the DC voltage of the positive bus to the ground and the DC voltage of the negative bus to the ground of the negative bus. In the existing circuit breaker working scenario, the closing coil HQ of the circuit breaker is connected between the positive bus and the negative bus in the power grid, and the opening coil TQ of the circuit breaker is also connected between the positive bus and the negative bus to realize the function of the circuit breaker in the power grid.

[0031] Here, the circuit breaker coil monitoring circuit has a grounding point, and the circuit breaker coil monitoring circuit is connected between the positive bus and the negative bus, and the voltage between the positive bus and the grounding point can be used as the positive bus to ground DC voltage, and the voltage between the negative bus and the grounding point can be used as the negative bus to ground DC voltage. Further, the circuit breaker coil monitoring circuit is connected to a monitoring controller to send the positive bus to ground DC voltage and the negative bus to ground DC voltage to the monitoring controller.

[0032] Furthermore, the closing coil monitoring circuit is connected between the positive busbar and the positive terminal of the closing coil HQ of the circuit breaker, and is used to collect the first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil HQ. Figure 2a As shown, the negative terminal of the closing coil HQ is connected to the negative bus, and the positive terminal of the closing coil HQ is connected to the output terminal of the closing coil monitoring circuit. Further, the positive terminal of the closing coil HQ is also connected to the positive bus through the circuit breaker normally open contact QF1, the first closing lockout relay HBJ1, the opening lockout relay auxiliary contact TBJV, the closing relay auxiliary contact HJ, the second closing lockout relay HBJ2, the opening position relay current limiting resistor Rtw and the opening position relay TWJ. Further, as Figure 1As shown, the closing coil monitoring circuit is connected to the monitoring controller to send the first current value to the monitoring controller.

[0033] Furthermore, the opening coil monitoring circuit is connected between the positive busbar and the positive terminal of the opening coil TQ of the circuit breaker, and is used to collect a second current value flowing from the opening coil monitoring circuit to the positive terminal of the opening coil TQ; in the existing working scenario of the circuit breaker, Figure 3a As shown, the negative terminal of the opening coil TQ is connected to the negative bus, and the positive terminal of the opening coil TQ is connected to the output terminal of the opening coil monitoring circuit. Further, the positive terminal of the opening coil TQ is also connected to the positive bus through the circuit breaker normally closed contact QF2, the first opening lockout relay TBJ1, the opening relay auxiliary contact TJ, the second opening lockout relay TBJ2, the closing position relay current limiting resistor Rhw and the closing position relay HWJ. Further, as Figure 1 As shown, the opening coil monitoring circuit is connected to the monitoring controller to send the second current value to the monitoring controller.

[0034] Furthermore, the monitoring controller is used to determine whether the positive bus and the negative bus are under-voltage based on the positive bus DC voltage to ground and the negative bus DC voltage to ground; specifically, the monitoring controller can determine whether the sum of the positive bus DC voltage to ground and the negative bus DC voltage to ground is greater than a preset DC voltage threshold. Among them, the preset DC voltage threshold is a judgment standard that determines that the positive bus and the negative bus are not under-voltage when the sum of the positive bus DC voltage to ground and the negative bus DC voltage to ground obtained in advance based on experiments or tests is greater than a value, and the value of the preset DC voltage threshold can be determined based on actual conditions. Further, if the sum of the positive bus DC voltage to ground and the negative bus DC voltage to ground is greater than the preset DC voltage threshold, it is determined that the positive bus and the negative bus are not under-voltage. Conversely, if the sum of the positive busbar DC voltage to ground and the negative busbar DC voltage to ground is not greater than the preset DC voltage threshold, it is determined that the positive busbar and the negative busbar are undervoltage, and an alarm message of undervoltage of the positive and negative buses can be sent to a remote host computer.

[0035] Furthermore, the monitoring controller is also used to determine whether the closing coil HQ is open-circuited based on the first current value when the positive bus and the negative bus are not undervoltage. Specifically, when there is no undervoltage between the positive and negative bus, the first current value can be compared with a preset normal current interval to determine whether the first current value is within the normal closing current interval. Among them, the normal closing current interval is a judgment standard for determining that the closing coil is not open-circuited when the first current value flowing from the closing coil monitoring circuit to the positive end of the closing coil is within a range obtained in advance based on experiments or tests, and the value of the normal closing current interval can be determined according to actual conditions. Here, if the first current value is not within the normal closing current interval, it can be determined that the closing coil HQ is open-circuited. Conversely, if the first current value is within the normal closing current interval, it can be determined that the closing coil HQ is not open-circuited.

[0036] Furthermore, the monitoring controller is also used to determine whether the opening coil TQ is open-circuited based on the second current value when the positive bus and the negative bus do not have an undervoltage condition. Specifically, when there is no undervoltage between the positive and negative busbars, the second current value can be compared with a pre-set normal current range to determine whether the second current value is within the normal opening current range. Among them, the normal opening current range is a judgment standard for determining that the opening coil is not open-circuited when the second current value flowing from the opening coil monitoring circuit to the positive end of the opening coil is within a range obtained in advance based on experiments or tests, and the value of the normal opening current range can be determined according to actual conditions. Here, if the second current value is not within the normal opening current range, it can be determined that the opening coil TQ is open-circuited. Conversely, if the second current value is within the normal opening current range, it can be determined that the opening coil TQ is not open-circuited.

[0037] The present invention provides a monitoring system for the closing coil and the opening coil of a circuit breaker. First, the positive bus and the negative bus where the circuit breaker is located are determined to be undervoltage through the DC voltage of the positive bus to the ground and the DC voltage of the negative bus to the ground. Then, when the positive bus and the negative bus are not undervoltage, it is determined whether the closing coil is open-circuited based on the first current value flowing from the closing coil monitoring circuit to the positive end of the closing coil, and it is determined whether the opening coil is open-circuited based on the second current value flowing from the opening coil monitoring circuit to the positive end of the closing coil. It is possible to comprehensively analyze whether the closing coil and the opening coil have open-circuit problems while considering the bus voltage to the ground of the bus, thereby enhancing the accuracy of the open-circuit monitoring of the closing coil and the opening coil of the circuit breaker.

[0038] In an optional embodiment, if Figure 4As shown, the circuit breaker coil monitoring circuit includes a first voltage-dividing resistor Rpp, a second voltage-dividing resistor Rpn, a first voltage collector PT1 and a second voltage collector PT2. The first voltage-dividing resistor Rpp and the second voltage-dividing resistor Rpn are connected in series between the positive bus and the parent line, and the first voltage-dividing resistor Rpp and the second voltage-dividing resistor Rpn are grounded; further, the first voltage collector PT1 is used to collect the first voltage drop across the first voltage-dividing resistor Rpp, and send the first voltage drop as the positive bus to ground DC voltage to the monitoring controller; further, the second voltage collector PT2 is used to collect the second voltage drop across the second voltage-dividing resistor Rpn, and send the second voltage drop as the negative bus to ground DC voltage to the monitoring controller.

[0039] Specifically, the first end of the first voltage-dividing resistor Rpp is connected to the positive bus, the second end of the first voltage-dividing resistor Rpp is connected to the first end of the second voltage-dividing resistor Rpn and is grounded, and the second end of the second voltage-dividing resistor Rpn is connected to the negative bus; here, a first protection resistor Rlp can be connected in series between the first end of the first voltage-dividing resistor Rpp and the positive bus, and a second protection resistor Rln can be connected in series between the first end of the second voltage-dividing resistor Rpn and the negative bus to perform overcurrent protection on the circuit.

[0040] Further, the first collecting end of the first voltage collector PT1 is connected to the first end of the first voltage-dividing resistor Rpp, and the second collecting end of the first voltage collector PT1 is connected to the second end of the first voltage-dividing resistor Rpp. The first voltage collector PT1 is used to collect the first voltage drop across the first voltage-dividing resistor Rpp, and determine the first voltage drop as the positive bus-to-ground DC voltage. Further, the signal output end of the first voltage collector PT1 is connected to a monitoring controller (not shown in the figure), and is used to send the positive bus-to-ground DC voltage to the monitoring controller.

[0041] Further, the first acquisition end of the second voltage collector PT2 is connected to the first end of the second voltage-dividing resistor Rpn, the second acquisition end of the second voltage collector PT2 is connected to the second end of the second voltage-dividing resistor Rpn, and the second voltage collector PT2 is used to collect the second voltage drop across the second voltage-dividing resistor Rpn, and determine the second voltage drop as the negative bus-to-ground DC voltage. Further, the signal output end of the second voltage collector PT2 is connected to the monitoring controller, and is used to send the negative bus-to-ground DC voltage to the monitoring controller.

[0042] The embodiment provided by the present application can be connected to the positive and negative bus bars where the circuit breaker is located through a circuit breaker coil monitoring circuit, and the voltage on the first voltage-dividing resistor is collected as the positive bus bar to ground DC voltage through the first voltage collector in the circuit breaker coil monitoring circuit, and the voltage on the second voltage-dividing resistor is collected as the negative bus bar to ground DC voltage through the second voltage collector in the circuit breaker coil monitoring circuit. The positive bus bar to ground DC voltage and the negative bus bar to ground DC voltage can be accurately obtained, and the ability to identify undervoltage conditions can be significantly improved, so as to improve the monitoring ability of whether the closing coil and the opening coil are short-circuited.

[0043] In an optional embodiment, the monitoring controller determines whether the closing coil is open-circuited based on the first current value in a manner including: first, the monitoring controller determines whether the first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil is less than a first preset current threshold; wherein the first preset current threshold is a judgment standard obtained in advance based on experiments or tests, and when the first current value flowing from the closing coil monitoring circuit to the positive terminal of the opening and closing coil is less than a value, it can be determined that the closing coil is open-circuited. The value of the first preset current threshold can be determined based on actual conditions.

[0044] Further, if the first current value is less than the first preset current threshold, it is determined that the closing coil is open-circuited. Conversely, if the first current value is not less than the first preset current threshold, it is determined that the closing coil is not open-circuited. As an example, if the first preset current threshold is 8 mA and the first current value is 10 mA, it can be determined that the closing coil is not open-circuited.

[0045] The embodiment provided in the present application can quickly determine whether a closing coil is short-circuited based on the relationship between a first current value flowing from a closing coil monitoring circuit into the positive terminal of the closing coil and a first preset current threshold, thereby improving the efficiency of short-circuit monitoring of the closing coil.

[0046] In an optional embodiment, if Figure 2a As shown, the closing coil monitoring circuit includes a first current sampling circuit, a first current sensor CT1 and a first optical coupling circuit breaker OP1.

[0047] Specifically, the first end of the first current sampling circuit is connected to the positive bus, the second end of the first current sampling circuit is connected to the first end of the normally open auxiliary contact QF3 of the circuit breaker, and the second end of the normally open auxiliary contact QF3 is connected to the positive end of the closing coil HQ. Here, the normally open auxiliary contact QF3 of the circuit breaker can be connected to the closing coil monitoring circuit to determine whether the reason why the first current value is less than the first preset current threshold is that the normally open auxiliary contact QF3 is not in place.

[0048] Further, the first optocoupler circuit breaker contact of the first optocoupler circuit breaker OP1 is connected in parallel with the normally open auxiliary contact QF3. Specifically, the first end of the first optocoupler circuit breaker contact of the first optocoupler circuit breaker OP1 is connected to the first end of the normally open auxiliary contact QF3, and the second end of the first optocoupler circuit breaker contact of the first optocoupler circuit breaker OP1 is connected to the second end of the normally open auxiliary contact QF3. Further, the first control end of the monitoring controller (not shown in the figure) is connected to the controlled end of the first optocoupler circuit breaker OP1, and is used to control the first optocoupler circuit breaker contact to be turned on or off. Further, the first current sensor CT1 is used to collect the first current value of the current flowing through the first current sampling circuit in real time, and send the first current value to the monitoring controller.

[0049] Further, the monitoring controller determines whether the first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil HQ is less than the first preset current threshold value, including:

[0050] First, the monitoring controller obtains the first current value from the first current sensor and determines whether the first current value is less than the first preset current threshold; further, if the first current value is less than the first preset current threshold, the first optical coupling circuit breaker contact is controlled to be turned on, and after a preset time period, the first current value is obtained from the first current sensor again, and it is determined whether the first current value is still less than the first preset current threshold; wherein, the length of the preset time period can be determined according to actual conditions. Here, if the reason for the first current value being less than the first preset current threshold is that the normally open auxiliary contact QF3 is not in place instead of the closing coil HQ being disconnected, then after the first optical coupling circuit breaker contact is turned on, the first current value should be restored to above the first preset current threshold. Further, the first optical coupling circuit breaker OP1 can isolate the monitoring controller from the closing coil monitoring circuit to prevent the signal sent by the monitoring controller from affecting the closing coil monitoring circuit. Here, when the first optical coupling circuit breaker contact of the first optical coupling circuit breaker OP1 is turned on, the current flowing out of the first current sampling current flows to the closing coil HQ through the first optical coupling circuit breaker OP1.

[0051] Further, if the first current value is still less than the first preset current threshold, it is determined that the first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil HQ is less than the first preset current threshold. Specifically, if the first current value obtained by the first current sensor is still less than the first preset current threshold after a preset time period has passed since the first optical coupling circuit breaker contact was turned on, it can be determined that the reason why the first current value is less than the first preset current threshold is not that the normally open auxiliary contact QF3 is not in place, but that the closing coil HQ is broken.

[0052] Conversely, if after a preset time period has passed since the first optocoupler circuit breaker contact was turned on, the first current sensor obtains the first current value which is not less than the first preset current threshold, it can be determined that the reason why the first current value is less than the first preset current threshold is that the normally open auxiliary contact QF3 has not made contact. At this time, an alarm message that the normally open auxiliary contact QF3 has not made contact can be issued to prompt relevant personnel to pay attention to investigation.

[0053] The embodiment provided in the present application can eliminate the situation where the first current value is low due to the failure of the normally open auxiliary contact of the circuit breaker to make contact, thereby improving the accuracy of circuit breaker monitoring for the closing coil.

[0054] In an optional embodiment, if Figure 2a As shown, the first current sampling circuit includes a first current limiting resistor R1 and a first current measuring resistor R2; the first end of the first current limiting resistor R1 is connected to the positive bus, the second end of the first current limiting resistor R1 is connected to the first end of the first current measuring resistor R2, and the second end of the first current measuring resistor R2 is connected to the first end of the normally open auxiliary contact QF3. The first current limiting resistor R1 is used to perform overcurrent protection on the first current sampling circuit to improve the stability of the system.

[0055] Further, such as Figure 2b As shown, the first current sensor CT1 includes a first voltage drop sensor, a first conditioning circuit and a first current collector. The first access end of the first voltage drop sensor is connected to the first end of the first current measuring resistor R2, the second access end of the first voltage drop sensor is connected to the second end of the first current measuring resistor R2, the output end of the first voltage drop sensor is connected to the input end of the first conditioning circuit, the output end of the first conditioning circuit is connected to the first current collector, and the output end of the first current collector is connected to the monitoring controller.

[0056] Specifically, the first voltage drop sensor is used to collect the first DC voltage drop value across the first current measuring resistor R2, and send the first DC voltage drop value to the first conditioning circuit. Furthermore, the first conditioning circuit is used to perform signal amplification processing on the first DC voltage drop value to obtain a first conditioned voltage drop value, and send the first conditioned voltage drop value to the first current collector. Here, using the first conditioning circuit to amplify the signal of the first DC voltage drop value can enhance the signal quality of the first DC voltage drop value.

[0057] Further, the first current collector is used to obtain the first conditioned voltage drop value, and perform analog-to-digital conversion processing on the first conditioned voltage drop value, and determine the first current value based on the first conditioned voltage drop value after analog-to-digital conversion processing. Here, the first current collector can be a digital signal processor connected to an analog-to-digital converter, which is used to convert the first conditioned voltage drop value in the form of an analog signal into the first conditioned voltage drop value in the form of a digital signal through the analog-to-digital converter, and the digital signal processor divides the first conditioned voltage drop value by the resistance of the first current measuring resistor R2 to obtain the first current value. The embodiment provided in the present application can quickly determine the first current value flowing through the first current measuring resistor, thereby improving the efficiency of the system in monitoring the circuit breaker of the closing coil.

[0058] In an optional embodiment, the monitoring controller determines whether the opening coil is open-circuited based on the second current value in a manner that includes: first, the monitoring controller determines whether the second current value flowing from the opening coil monitoring circuit to the positive end of the opening coil is less than a second preset current threshold; wherein the second preset current threshold is a judgment standard obtained in advance based on experiments or tests, and when the second current value flowing from the opening coil monitoring circuit to the positive end of the opening coil is less than a value, it can be determined that the opening coil is open-circuited. The value of the second preset current threshold can be determined based on actual conditions.

[0059] Further, if the second current value is less than the second preset current threshold, it is determined that the opening coil is open-circuited. Conversely, if the second current value is not less than the second preset current threshold, it is determined that the opening coil is not open-circuited. As an example, if the second preset current threshold is 8 mA and the second current value is 10 mA, it can be determined that the opening coil is not open-circuited.

[0060] The embodiment provided in the present application can quickly determine whether the opening coil is open-circuited based on the relationship between the second current value flowing from the opening coil monitoring circuit into the positive end of the opening coil and the second preset current threshold, thereby improving the efficiency of the open-circuit monitoring of the opening coil.

[0061] In an optional embodiment, if Figure 3aAs shown, the trip coil monitoring circuit includes a second current sampling circuit, a second current sensor CT2 and a second optical coupling circuit breaker OP2.

[0062] Specifically, the first end of the second current sampling circuit is connected to the positive bus, the second end of the second current sampling circuit is connected to the first end of the normally closed auxiliary contact QF4 of the circuit breaker, and the second end of the normally closed auxiliary contact QF4 is connected to the positive end of the opening coil TQ. Here, the normally closed auxiliary contact QF2 of the circuit breaker can be connected to the opening coil monitoring circuit to determine whether the reason why the second current value is less than the second preset current threshold is that the normally closed auxiliary contact QF4 is not in place.

[0063] Further, the second optocoupler circuit breaker contact of the second optocoupler circuit breaker is connected in parallel with the normally closed auxiliary contact QF4. Specifically, the first end of the second optocoupler circuit breaker contact of the second optocoupler circuit breaker OP2 is connected to the first end of the normally closed auxiliary contact QF4, and the second end of the second optocoupler circuit breaker contact of the second optocoupler circuit breaker OP2 is connected to the second end of the normally closed auxiliary contact QF4. Further, the second control end of the monitoring controller (not shown in the figure) is connected to the controlled end of the second optocoupler circuit breaker OP2, and is used to control the conduction or disconnection of the second optocoupler circuit breaker contact. Further, the second current sensor CT2 is used to collect the second current value of the current flowing through the second current sampling circuit in real time, and send the second current value to the monitoring controller.

[0064] Further, the monitoring controller determines whether the second current value flowing from the opening coil monitoring circuit to the positive terminal of the opening coil TQ is less than the second preset current threshold value, including:

[0065] First, the monitoring controller obtains the second current value from the second current sensor CT2, and determines whether the second current value is less than the second preset current threshold; further, if the second current value is less than the second preset current threshold, the second optical coupling circuit breaker contact is turned on, and after a preset time period, the second current value is obtained from the second current sensor CT2 again, and it is determined whether the second current value is still less than the second preset current threshold; wherein, the length of the preset time period can be determined according to actual conditions. Here, if the reason for the second current value being less than the second preset current threshold is that the normally closed auxiliary contact QF4 is not in place instead of the opening coil TQ being disconnected, then after the second optical coupling circuit breaker contact is turned on, the second current value should be restored to above the second preset current threshold. Further, the second optical coupling circuit breaker OP2 can isolate the monitoring controller from the opening coil monitoring circuit to prevent the signal sent by the monitoring controller from affecting the opening coil monitoring circuit. Here, when the second optical coupling circuit breaker contact of the second optical coupling circuit breaker OP2 is turned on, the current flowing out of the second current sampling current flows to the opening coil TQ through the second optical coupling circuit breaker OP2.

[0066] Further, if the second current value is less than the second preset current threshold, it is determined that the second current value flowing from the opening coil monitoring circuit to the positive terminal of the opening coil TQ is less than the second preset current threshold. Specifically, if after the second optical coupling circuit breaker contact is turned on and a preset time period has passed, the second current value obtained by the second current sensor CT2 is still less than the second preset current threshold, it can be determined that the reason why the second current value is less than the second preset current threshold is not that the normally closed auxiliary contact QF4 is not in place, but that the opening coil TQ is broken.

[0067] Conversely, if after a preset time period has passed since the second optocoupler circuit breaker contact was turned on, the second current value obtained by the second current sensor CT2 is not less than the second preset current threshold, it can be determined that the reason why the second current value is less than the second preset current threshold is that the normally closed auxiliary contact QF4 has not been in contact. At this time, an alarm message that the normally closed auxiliary contact QF4 has not been in contact can be issued to prompt relevant personnel to pay attention to investigation.

[0068] The embodiment provided in the present application can eliminate the situation where the second current value is low due to the normally closed auxiliary contact of the circuit breaker not being in contact, thereby improving the accuracy of circuit breaker monitoring of the opening coil.

[0069] In an optional embodiment, if Figure 3aAs shown, the second current sampling circuit includes a second current limiting resistor R3 and a second current measuring resistor R4; the first end of the second current limiting resistor R3 is connected to the positive bus, the second end of the second current limiting resistor R3 is connected to the first end of the second current measuring resistor R4, and the second end of the second current measuring resistor R4 is connected to the first end of the normally closed auxiliary contact QF4. The second current limiting resistor R3 is used to perform overcurrent protection on the second current sampling circuit to improve the stability of the system.

[0070] Further, such as Figure 3b As shown, the second current sensor CT2 includes a second voltage drop sensor, a second conditioning circuit and a second current collector. The first access end of the second voltage drop sensor is connected to the first end of the second current measuring resistor R4, the second access end of the second voltage drop sensor is connected to the second end of the second current measuring resistor R4, the output end of the second voltage drop sensor is connected to the input end of the second conditioning circuit, the output end of the second conditioning circuit is connected to the second current collector, and the output end of the second current collector is connected to the monitoring controller.

[0071] Specifically, the second voltage drop sensor is used to collect the second DC voltage drop value across the second current measuring resistor R4, and send the second DC voltage drop value to the second conditioning circuit. Further, the second conditioning circuit is used to perform signal amplification processing on the second DC voltage drop value to obtain a second conditioned voltage drop value, and send the second conditioned voltage drop value to the second current collector. Here, using the second conditioning circuit to amplify the signal of the second DC voltage drop value can enhance the signal quality of the second DC voltage drop value.

[0072] Further, the second current collector is used to obtain the second conditioned voltage drop value, and perform analog-to-digital conversion processing on the second conditioned voltage drop value, and determine the second current value based on the second conditioned voltage drop value after the analog-to-digital conversion processing. Here, the second current collector can be a digital signal processor connected to an analog-to-digital converter, which is used to convert the second conditioned voltage drop value in the form of an analog signal into the second conditioned voltage drop value in the form of a digital signal through the analog-to-digital converter, and the digital signal processor divides the second conditioned voltage drop value by the resistance of the second current measuring resistor R4 to obtain the second current value. The embodiment provided in the present application can quickly determine the second current value flowing through the second current measuring resistor, thereby improving the efficiency of the system in monitoring the circuit breaker of the closing coil.

[0073] In an optional embodiment, the first voltage collector is further used to collect the first AC voltage value of the first voltage-dividing resistor, and the second voltage collector is further used to collect the second AC voltage value of the second voltage-dividing resistor. Here, when AC current enters the positive and negative busbars, the AC current will form an AC voltage value on the first voltage-dividing resistor and the second voltage-dividing resistor.

[0074] Furthermore, the monitoring controller is also used to determine whether the first AC voltage value and the second AC voltage value are greater than a preset AC voltage threshold value, wherein the preset AC voltage threshold value is a preset criterion for determining whether AC current is introduced into the positive and negative busbars.

[0075] Further, if the first AC voltage value or the second AC voltage value is greater than the preset AC voltage threshold, it is determined that the positive bus and the negative bus have AC intrusion. Conversely, if neither the first AC voltage value nor the second AC voltage value is greater than the preset AC voltage threshold, it is determined that the positive bus and the negative bus do not have AC intrusion.

[0076] Furthermore, when the monitoring controller determines that AC has entered the positive and negative busbars where the circuit breaker is located, an AC intrusion alarm message can be sent to the host computer to remind relevant staff to pay attention to the investigation. The embodiment provided by the present application can monitor whether AC has entered the busbar where the circuit breaker is located, enriching the functions of the monitoring system of the closing coil and the opening coil of the circuit breaker.

[0077] The present invention provides a monitoring system for a closing coil and an opening coil of a circuit breaker, wherein a closing coil monitoring circuit and an opening coil monitoring circuit are respectively added to conventional closing coils and opening coils, and optical coupling relay contacts connected in parallel with auxiliary contacts are respectively added to the above-mentioned closing coil monitoring circuit and opening coil monitoring circuit, and a monitoring branch of the DC voltage of the positive and negative busbars to the ground and its AC component is added. Whether the positive busbar and the negative busbar where the circuit breaker is located are undervoltage can be determined through the DC voltage of the positive busbar to the ground and the DC voltage of the negative busbar to the ground of the negative line. When the positive bus and the negative bus are not undervoltage, the closing coil is determined to be short-circuited based on the first current value flowing from the closing coil monitoring circuit into the positive end of the closing coil, and the opening coil is determined to be short-circuited based on the second current value flowing from the opening coil monitoring circuit into the positive end of the opening coil, and the influence of the normally open auxiliary contact and the normally closed auxiliary contact on the monitoring work can be eliminated. Considering the bus-to-ground voltage of the bus, the closing coil and the opening coil can be comprehensively analyzed to see if there is a short circuit, thereby enhancing the accuracy of the short circuit monitoring of the closing coil and the opening coil of the circuit breaker. Furthermore, the technical solution provided by the present application can monitor whether there is an AC intrusion phenomenon in the positive and negative busbars where the circuit breaker is located, and timely issue an alarm message when an AC intrusion phenomenon occurs in the positive and negative busbars, thereby increasing the functions that can be realized by the system.

[0078] The above serial numbers of this application are only for description and do not represent the advantages and disadvantages of the implementation scenarios. The above disclosure is only a few specific implementation scenarios of this application, but this application is not limited to them, and any changes that can be thought of by technicians in this field should fall within the scope of protection of this application.

Claims

1. A monitoring system for closing coil and opening coil of a circuit breaker, used for monitoring the breaking of closing coil and opening coil of the circuit breaker, characterized in that: The monitoring system of the closing coil and the opening coil of the circuit breaker comprises a monitoring controller, a circuit breaker coil monitoring circuit, a closing coil monitoring circuit and an opening coil monitoring circuit; The circuit breaker coil monitoring circuit is arranged between the positive bus and the negative bus where the circuit breaker is located, and is used to collect the DC voltage of the positive bus to the ground and the DC voltage of the negative bus to the ground; The closing coil monitoring circuit is connected between the positive busbar and the positive terminal of the closing coil of the circuit breaker, and is used to collect a first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil; the opening coil monitoring circuit is connected between the positive busbar and the positive terminal of the opening coil of the circuit breaker, and is used to collect a second current value flowing from the opening coil monitoring circuit to the positive terminal of the opening coil; The monitoring controller is used to determine whether the positive bus and the negative bus are undervoltage based on the positive bus-to-ground DC voltage and the negative bus-to-ground DC voltage, and when the positive bus and the negative bus are not undervoltage, determine whether the closing coil is open-circuited based on the first current value, and determine whether the opening coil is open-circuited based on the second current value.

2. The monitoring system for closing coil and opening coil of circuit breaker according to claim 1, characterized in that: The circuit breaker coil monitoring circuit includes a first voltage dividing resistor, a second voltage dividing resistor, a first voltage collector and a second voltage collector; The first voltage-dividing resistor and the second voltage-dividing resistor are connected in series between the positive bus and the negative bus, and the first voltage-dividing resistor and the second voltage-dividing resistor are grounded; The first voltage collector is used to collect a first voltage drop across the first voltage-dividing resistor, and send the first voltage drop as the positive bus-to-ground DC voltage to the monitoring controller; The second voltage collector is used to collect a second voltage drop across the second voltage-dividing resistor, and send the second voltage drop as the negative bus-to-ground DC voltage to the monitoring controller.

3. The monitoring system for closing coil and opening coil of circuit breaker according to claim 2, characterized in that: The monitoring controller determines whether the positive bus and the negative bus are undervoltage based on the DC voltage of the positive bus to ground and the DC voltage of the negative bus to ground, including: The monitoring controller determines whether the sum of the positive busbar-to-ground DC voltage and the negative busbar-to-ground DC voltage is greater than a preset DC voltage threshold; If the sum of the positive busbar-to-ground DC voltage and the negative busbar-to-ground DC voltage is greater than the preset DC voltage threshold, it is determined that the positive busbar and the negative busbar are not undervoltage.

4. The monitoring system for closing coil and opening coil of circuit breaker according to claim 1, characterized in that: The monitoring controller determines whether the closing coil is open circuit based on the first current value, including: The monitoring controller determines whether a first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil is less than a first preset current threshold; If the first current value is less than the first preset current threshold, it is determined that the closing coil is open-circuited.

5. The monitoring system for closing coil and opening coil of circuit breaker according to claim 4, characterized in that: The closing coil monitoring circuit includes a first current sampling circuit, a first current sensor and a first optical coupling circuit breaker; The first end of the first current sampling circuit is connected to the positive bus, the second end of the first current sampling circuit is connected to the first end of the normally open auxiliary contact of the circuit breaker, and the second end of the normally open auxiliary contact is connected to the positive end of the closing coil; The first optical coupling circuit breaker contact of the first optical coupling circuit breaker is connected in parallel with the normally open auxiliary contact; the first control end of the monitoring controller is connected to the controlled end of the first optical coupling circuit breaker, and is used to control the first optical coupling circuit breaker contact to be turned on or off; The first current sensor is used to collect a first current value of the current flowing through the first current sampling circuit, and send the first current value to the monitoring controller; The monitoring controller determines whether a first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil is less than a first preset current threshold, including: The monitoring controller obtains the first current value from the first current sensor, and determines whether the first current value is less than a first preset current threshold; If the first current value is less than the first preset current threshold, the first optical coupling circuit breaker contact is controlled to be turned on, and after a preset time period, the first current value is obtained from the first current sensor again, and it is determined whether the first current value is still less than the first preset current threshold; If the first current value is still smaller than the first preset current threshold, it is determined that the first current value flowing from the closing coil monitoring circuit to the positive terminal of the closing coil is smaller than the first preset current threshold.

6. The monitoring system for closing coil and opening coil of circuit breaker according to claim 1, characterized in that: The monitoring controller determines whether the trip coil is open circuit based on the second current value, including: The monitoring controller determines whether a second current value flowing from the opening coil monitoring circuit to the positive terminal of the opening coil is less than a second preset current threshold; If the second current value is less than the second preset current threshold, it is determined that the trip coil is open-circuited.

7. The monitoring system for closing coil and opening coil of circuit breaker according to claim 6, characterized in that: The opening coil monitoring circuit includes a second current sampling circuit, a second current sensor and a second optical coupling circuit breaker; The first end of the second current sampling circuit is connected to the positive bus, the second end of the second current sampling circuit is connected to the first end of the normally closed auxiliary contact of the circuit breaker, and the second end of the normally closed auxiliary contact is connected to the positive end of the opening coil; The second optical coupling circuit breaker contact of the second optical coupling circuit breaker is connected in parallel with the normally closed auxiliary contact; the second control terminal of the monitoring controller is connected to the controlled terminal of the second optical coupling circuit breaker for controlling the second optical coupling circuit breaker contact to be turned on or off; The second current sensor is used to collect a second current value of the current flowing through the second current sampling circuit, and send the second current value to the monitoring controller; The monitoring controller determines whether a second current value flowing from the opening coil monitoring circuit to the positive terminal of the opening coil is less than a second preset current threshold, including: The monitoring controller obtains a second current value from the second current sensor, and determines whether the second current value is less than the second preset current threshold; If the second current value is less than the second preset current threshold, the second optical coupling circuit breaker contact is turned on, and after a preset time period, the second current value is obtained from the second current sensor again, and it is determined whether the second current value is still less than the second preset current threshold; If the second current value is still smaller than the second preset current threshold, it is determined that the second current value flowing from the opening coil monitoring circuit to the positive terminal of the opening coil is smaller than the second preset current threshold.

8. The monitoring system for closing coil and opening coil of circuit breaker according to claim 3, characterized in that: The first voltage collector is further used to collect a first AC voltage value of the first voltage-dividing resistor, and the second voltage collector is further used to collect a second AC voltage value of the second voltage-dividing resistor; The monitoring controller is also used to determine whether the first AC voltage value and the second AC voltage value are greater than a preset AC voltage threshold. If the first AC voltage value or the second AC voltage value is greater than the preset AC voltage threshold, it is determined that AC inrush exists in the positive bus and the negative bus.

9. The monitoring system for closing coil and opening coil of circuit breaker according to claim 5, characterized in that: The first current sampling circuit includes a first current limiting resistor and a first current measuring resistor; the first end of the first current limiting resistor is connected to the positive bus, the second end of the first current limiting resistor is connected to the first end of the first current measuring resistor, and the second end of the first current measuring resistor is connected to the first end of the normally open auxiliary contact; The first current sensor includes a first voltage drop sensor, a first conditioning circuit and a first current collector; The first voltage drop sensor is used to collect a first DC voltage drop value across the first current measuring resistor and send the first DC voltage drop value to the first conditioning circuit; The first conditioning circuit is used for performing signal amplification processing on the first DC voltage drop value to obtain a first conditioned voltage drop value, and sending the first conditioned voltage drop value to the first current collector; The first current collector is used to obtain the first conditioned voltage drop value, perform analog-to-digital conversion on the first conditioned voltage drop value, and determine the first current value based on the first conditioned voltage drop value after the analog-to-digital conversion.

10. The monitoring system for closing coil and opening coil of circuit breaker according to claim 7, characterized in that: The second current sampling circuit includes a second current limiting resistor and a second current measuring resistor; the first end of the second current limiting resistor is connected to the positive bus, the second end of the second current limiting resistor is connected to the first end of the second current measuring resistor, and the second end of the second current measuring resistor is connected to the first end of the normally closed auxiliary contact; The second current sensor includes a second voltage drop sensor, a second conditioning circuit and a second current collector; The second voltage drop sensor is used to collect a second voltage drop value across the second current measuring resistor and send the second voltage drop value to the second conditioning circuit; The second conditioning circuit is used for performing signal amplification processing on the second voltage drop value to obtain a second conditioned voltage drop value, and sending the second conditioned voltage drop value to the second current collector; The second current collector is used to obtain the second conditioned voltage drop value, perform analog-to-digital conversion on the second conditioned voltage drop value, and determine the second current value based on the second conditioned voltage drop value after the analog-to-digital conversion.

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