Method and device for detecting health degree of intelligent capacitor and intelligent capacitor

Abstract

The invention provides a health degree detection method and device of an intelligent capacitor and the intelligent capacitor, and belongs to the technical field of element detection.The health degree detection method comprises the steps that first, a first voltage signal and a second voltage signal of a relay contact end in the intelligent capacitor are obtained respectively; and then, a control signal is sent to a relay to control the connection or disconnection of the contact end of the relay, the sending time of the control signal is recorded, the contact voltage difference is obtained according to the first voltage signal and the second voltage signal, the change time of the contact voltage difference is recorded, and the temperature information and the current information of the load capacitor of the intelligent capacitor are obtained. And finally, obtaining a health detection result of the intelligent capacitor according to at least one of the temperature information, the current information, the contact pressure difference, the sending time and the change time. Therefore, health detection of the intelligent capacitor is realized.

Description

Technical Field

[0001] The present application relates to the field of component detection technology, and specifically to a health detection method and device for a smart capacitor and a smart capacitor. Background Art

[0002] Smart capacitors are an important component of the power system, including relays and load capacitors. According to the reactive power demand of the power system, relays control the switching on and off of load capacitors, thereby realizing dynamic regulation of the reactive power of the power grid and improving the power factor of the power grid. This can not only effectively improve the utilization rate of power equipment, but also significantly reduce the operating cost of the power grid.

[0003] However, in actual use, the operation of the power system is affected by many factors such as temperature, harmonics and load, and the fluctuation range is large, which makes the operating environment of smart capacitors more complex and changeable, which can easily lead to performance degradation or even failure, and then increase load loss, which will further increase the fluctuation of the power system. Therefore, how to detect the health of smart capacitors to avoid the problem that smart capacitors cannot be effectively compensated due to failures. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present application provides a method and device for detecting the health of a smart capacitor and a smart capacitor.

[0005] In a first aspect, the present application provides a method for detecting the health of a smart capacitor, comprising:

[0006] The intelligent capacitor comprises a relay, a load capacitor and a controller, and is characterized in that it comprises:

[0007] Respectively obtaining a first voltage signal and a second voltage signal at both ends of a contact of a relay in the intelligent capacitor;

[0008] Sending a control signal to the relay to control the contact end of the relay to be turned on or off, and recording the sending time of the control signal;

[0009] Obtaining a contact pressure difference according to the first voltage signal and the second voltage signal, and recording a change time of the contact pressure difference;

[0010] Acquiring temperature information and current information of the load capacitance of the smart capacitor;

[0011] A health detection result of the smart capacitor is obtained according to at least one of the temperature information, the current information, the contact pressure difference, the sending time and the changing time.

[0012] Optionally, the control signal is a conduction control signal, and obtaining a health detection result of the smart capacitor according to at least one of the temperature information, the current information, the contact pressure difference, the sending time, and the changing time includes:

[0013] Within a first preset time period from the moment when the conduction control signal is sent, determining whether the contact pressure difference is less than a first preset pressure difference threshold;

[0014] If the contact pressure difference is greater than or equal to the first preset pressure difference threshold, determining that the health detection result of the relay is a closing abnormality;

[0015] If the contact pressure difference is less than the first preset pressure difference threshold, a contact resistance value is obtained according to the contact pressure difference, and it is determined whether the contact resistance value is less than a preset resistance threshold;

[0016] If the contact resistance value is greater than or equal to the preset resistance threshold, it is determined that the health detection result of the relay is abnormal contact wear;

[0017] If the contact resistance value is less than the preset resistance threshold, the conduction response time is obtained according to the sending time of the conduction control signal and the change time, and it is determined whether the conduction response time is less than a second preset time;

[0018] If the conduction response time is greater than or equal to the second preset time, determining that the health detection result of the relay is a closing timeout abnormality;

[0019] If the conduction response time is less than the second preset time, it is determined that the health detection result of the relay is operating normally.

[0020] Optionally, the control signal is a disconnection control signal, and the health detection result of the relay of the smart capacitor is obtained according to the contact pressure difference, the sending time and the changing time, including:

[0021] Within a third preset time period from the moment when the disconnection control signal is sent, determining whether the contact pressure difference is greater than a second preset pressure difference threshold;

[0022] If the contact pressure difference is less than or equal to the second preset pressure difference threshold, determining that the health detection result of the relay is disconnection abnormality;

[0023] If the contact pressure difference is greater than the second preset pressure difference threshold, the disconnection response time is obtained according to the sending time of the disconnection control signal and the change time, and it is determined whether the disconnection response time is less than a fourth preset time;

[0024] If the disconnection response time is greater than or equal to the fourth preset time, determining that the health detection result of the relay is a disconnection timeout abnormality;

[0025] If the disconnection response time is less than the fourth preset time, it is determined that the health detection result of the relay is normal disconnection.

[0026] Optionally, the temperature information includes a first temperature value inside a load capacitor in the smart capacitor and a second temperature value of a loop where the load capacitor is located; the current information includes a rated current value of the load capacitor and an actual current value obtained by sampling the current of the loop where the load capacitor is located;

[0027] The obtaining of the health detection result of the smart capacitor according to at least one of the temperature information, the current information, the contact pressure difference, the sending time and the changing time also includes:

[0028] A health detection result of the load capacitor is obtained according to the first temperature value, the second temperature value, the actual current value and the rated current value.

[0029] Optionally, the method further includes a method for obtaining the rated current value of the load capacitor, the method comprising:

[0030] Sampling the voltage source of the loop where the load capacitor is located to obtain the power supply frequency and the output voltage;

[0031] Obtaining the rated capacitance of the load capacitor;

[0032] The rated current value of the load capacitor is obtained according to the power supply frequency, the output voltage and the rated capacitance.

[0033] Optionally, obtaining a health detection result of the load capacitor according to the first temperature value, the second temperature value, the actual current value, and the rated current value includes:

[0034] Determine whether the difference between the actual current value and the rated current value is greater than a preset error value, and compare the first temperature value and the second temperature value with preset temperature thresholds respectively;

[0035] If the difference between the actual current value and the rated current value is greater than the preset error value or the first temperature value is greater than the preset temperature threshold or the second temperature value is greater than the preset temperature threshold, then the health detection result of the load capacitor is determined to be abnormal;

[0036] If the difference between the actual current value and the rated current value is less than the preset error value and the first temperature value and the second temperature value are both less than or equal to the preset temperature threshold, it is determined that the health detection result of the load capacitor is normal.

[0037] In a second aspect, in one embodiment, the present application provides a health detection device for a smart capacitor, comprising:

[0038] A voltage sampling circuit, used for acquiring a first voltage signal and a second voltage signal of a contact end of a relay in the smart capacitor;

[0039] A controller is connected to the voltage sampling circuit and is used to obtain a health detection result of the smart capacitor according to the first voltage signal and the second voltage signal.

[0040] Optionally, the contact end includes a first contact and a second contact, and the voltage sampling circuit includes a first voltage dividing subcircuit for collecting the first voltage signal and a second voltage dividing subcircuit for collecting the second voltage signal;

[0041] The first voltage dividing subcircuit includes a first resistor and a second resistor;

[0042] The first end of the first resistor is connected to the first contact, and the second end is connected to the first end of the second resistor and the controller; the second end of the second resistor is grounded;

[0043] The second voltage dividing sub-circuit includes a third resistor and a fourth resistor;

[0044] The first end of the third resistor is connected to the second contact, and the second end is connected to the first end of the fourth resistor and the controller; the second end of the fourth resistor is grounded.

[0045] Optionally, it also includes a temperature detection circuit and a current detection circuit;

[0046] The temperature detection circuit is used to obtain a first temperature value inside a load capacitor in the smart capacitor and a second temperature value of a loop where the load capacitor is located;

[0047] The current detection circuit is used to sample the current of the loop where the load capacitor is located to obtain the actual current value;

[0048] The controller is connected to the temperature detection circuit and the current detection circuit, and is used to obtain the rated current value of the load capacitor, and obtain a health detection result of the load capacitor based on the first temperature value, the second temperature value, the actual current value and the rated current value.

[0049] In a third aspect, in one embodiment, the present application provides a smart capacitor, including: a voltage source, a drive control circuit, a relay, a load capacitor, and a health monitoring device of the smart capacitor;

[0050] The contact end of the relay is connected in series with the voltage source, the load capacitor and the current detection circuit, and the coil end is connected with the drive control circuit, so as to control the connection and disconnection of the load capacitor;

[0051] The controller is connected to the voltage sampling circuit, the current detection circuit, the temperature detection circuit and the drive control circuit, and is used to send a control signal to the drive control circuit to control the on and off of the relay through the drive control circuit, and obtain a health detection result of the smart capacitor according to the first voltage signal, the second voltage signal, the first temperature value, the second temperature value, the actual current value and the rated current value.

[0052] In summary, in the present application, firstly, the first voltage signal and the second voltage signal of the contact end of the relay in the intelligent capacitor are respectively obtained to implement the capture of the voltage state of the contact end of the relay. Secondly, the conduction or disconnection of the contact end is controlled by sending a control signal to the relay, and the sending time of the control signal is recorded. Then, the contact pressure difference is calculated according to the obtained first voltage signal and the second voltage signal, and the change time of the contact pressure difference is recorded. The change of the contact pressure difference can reflect the contact state of the relay contact, and the sending time of the control signal and the change time of the contact pressure difference can reflect whether the response of the relay is timely, so as to analyze the sensitivity of the load capacitor connection and cut-out. In addition, the working state of the load capacitor can be obtained through temperature information and current information. In this way, according to at least one of the temperature information, current information, contact pressure difference, sending time and change time, the health detection of the relay or the load capacitor can be realized, and because there is a close connection between the state of the relay and the load capacitor and the working state of the intelligent capacitor, the health detection of the intelligent capacitor is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0054] Figure 1 This is a schematic diagram of an application scenario of a method for detecting the health of a smart capacitor in one embodiment of the present application;

[0055] Figure 2This is a flow chart of a method for detecting the health of a smart capacitor in one embodiment of the present application;

[0056] Figure 3 This is a flow chart of a method for detecting the health of a relay conduction state in one embodiment of the present application;

[0057] Figure 4 A timing diagram of a relay response in one embodiment of the present application;

[0058] Figure 5 This is a flow chart of a method for detecting the health of a relay in a disconnected state in an embodiment of the present application;

[0059] Figure 6 This is a schematic diagram of a health detection device for a smart capacitor in one embodiment of the present application.

[0060] Explanation of the accompanying drawings: 1. Voltage sampling circuit; 2. Controller; 3. Temperature detection circuit; 4. Current detection circuit; 5. Communication circuit. DETAILED DESCRIPTION

[0061] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0062] In the description of the present application, it should be understood that the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In the present application, the word "exemplary" is used to mean "used as an example, illustration or description". Any embodiment described as "exemplary" in the present application is not necessarily interpreted as being more preferred or more advantageous than other embodiments. In order to enable any technician in the field to implement and use the present application, the following description is given. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present application can also be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid unnecessary details that make the description of the present application obscure. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the widest range of principles and features disclosed in the present application.

[0063] The health detection method of the smart capacitor in the embodiment of the present application is applied to the smart capacitor, such as Figure 1 As shown, Figure 1 The present invention is a schematic diagram of an application scenario of a health detection method for a smart capacitor in an embodiment of the present application. The smart capacitor includes a controller, a drive control circuit, a relay, and a load capacitor; the controller determines whether to connect the load capacitor to compensate the power factor of the power system according to preset parameters and real-time measured data of the power system, and outputs a control signal. The drive control circuit receives a control signal from the controller and converts the control signal into a signal that can drive the relay to act, thereby ensuring that the control signal issued by the controller can be accurately responded to by the relay. The contact end of the relay is connected in series between the voltage source and the load capacitor, and the coil end is connected to the drive control circuit. The coil end of the relay receives the control signal converted by the drive control circuit to switch the contact end of the controller. When the contact end of the relay is disconnected, the voltage source and the load capacitor are disconnected, and the load capacitor is cut out of the power system. When the contact end of the relay is turned on, the voltage source and the load capacitor are turned on, and the load capacitor is connected to the power system for compensation, which helps to improve the stability and efficiency of the power system.

[0064] In order to achieve stable operation of the smart capacitor, the present application monitors the health of the smart capacitor.

[0065] First, as Figure 2 As shown, in one embodiment, the present application provides a method for detecting the health of a smart capacitor. The method for detecting the health of a smart capacitor includes steps S101 to S104, which are described in detail below.

[0066] Step S101: respectively obtaining a first voltage signal and a second voltage signal of a contact end of a relay in a smart capacitor.

[0067] As an example, the first voltage signal and the second voltage signal represent the voltages at both sides of the contact end, respectively. When the contact end of the circuit breaker is turned on, the contact end is equivalent to a wire, and the voltages at both ends of the contact end should be basically the same. When the contact end of the circuit breaker is turned off, the voltage on one side of the contact end is close to the voltage source connected to it, and the voltage on the other side of the contact end is close to zero.

[0068] Step S102: Send a control signal to the relay to control the contact end of the relay to be turned on or off, and record the time when the control signal is sent.

[0069] As an example, the control signal includes a conduction control signal and a disconnection control signal. When the power system requires reactive power compensation, a conduction control signal is sent to the relay to connect the load capacitor in the smart capacitor to the power system. When the power system does not require reactive power compensation, a disconnection control signal is sent to the relay to disconnect the connection between the power system and the load capacitor.

[0070] Step S103: obtaining a contact pressure difference according to the first voltage signal and the second voltage signal, and recording a change time of the contact pressure difference.

[0071] As an example, the change moment of the contact pressure difference refers to the moment when the change amount of the contact pressure difference in a unit time exceeds a preset value. For example, when the contact pressure difference changes from 12V to 1V in 1 second, this moment is recorded as the change moment.

[0072] Step S104: Acquire temperature information and current information of the load capacitance of the smart capacitor.

[0073] The temperature information includes a first temperature value inside the load capacitor in the smart capacitor and a second temperature value of the loop where the load capacitor is located; the current information includes a rated current value of the load capacitor and an actual current value obtained by sampling the current of the loop where the load capacitor is located. As an example, the first temperature value may be the temperature between the two plates of the load capacitor.

[0074] The circuit where the load capacitor is located refers to the circuit composed of the voltage source, the relay and the load capacitor, that is, when the relay is turned on, the output voltage of the voltage source flows to the load capacitor through the relay. As an example, the second temperature value can collect the temperature value of the contact end of the relay.

[0075] As an example, the rated current value of the load capacitor will be affected by the voltage source connected to it, that is, the fluctuation of the power system. The higher the output voltage and the higher the frequency of the voltage source, the higher the rated current value of the load capacitor will be.

[0076] Step S105: Obtain a health detection result of the smart capacitor according to at least one of the temperature information, the current information, the contact pressure difference, the sending time, and the changing time.

[0077] In the above implementation, first, the first voltage signal and the second voltage signal of the contact end of the relay in the smart capacitor are respectively obtained to implement the capture of the voltage state of the contact end of the relay. Secondly, the conduction or disconnection of the contact end of the relay is controlled by sending a control signal to the relay, and the sending time of the control signal is recorded. Then, the contact pressure difference is calculated according to the obtained first voltage signal and the second voltage signal, and the change time of the contact pressure difference is recorded. The change of the contact pressure difference can reflect the contact state of the relay contact, and the sending time of the control signal and the change time of the contact pressure difference can reflect whether the response of the relay is timely, so as to analyze the sensitivity of the load capacitor connection and cut-out. In addition, the working state of the load capacitor can be obtained through temperature information and current information. In this way, according to at least one of the temperature information, current information, contact pressure difference, sending time and change time, the health detection of the relay or the load capacitor can be realized, and because there is a close connection between the state of the relay and the load capacitor and the working state of the smart capacitor, the health detection of the smart capacitor is realized.

[0078] Reference Figure 3 In some embodiments, the control signal is a conduction control signal, and step S104 may include steps S201 to S207, which are described in detail below.

[0079] Step S201: within a first preset time period from the moment of sending the conduction control signal, determine whether the contact pressure difference is less than a first preset pressure difference threshold. If the contact pressure difference is greater than or equal to the first preset pressure difference threshold, execute step S202; if the contact pressure difference is less than the first preset pressure difference threshold, execute step S203.

[0080] Among them, the first preset pressure difference threshold is the voltage difference threshold for judging whether the contact end is closed normally. The first preset pressure difference threshold is less than the output voltage of the voltage source. For example, the first preset pressure difference threshold can be one tenth, one twentieth or other value of the output voltage of the voltage source, as long as it can reflect that the contact pressure difference of the circuit breaker has a significant change, that is, it reflects that the contact pressure difference changes from close to the output voltage of the voltage source to less than the first preset pressure difference threshold.

[0081] Among them, the first preset time length is a preset time window, which is used to continuously detect the contact pressure difference within the time window after sending the conduction control signal. If the contact pressure difference is less than the first preset pressure difference threshold within the first preset time length, it means that the contact end of the relay has been normally closed; if the contact pressure difference is equal to or greater than the first preset pressure difference threshold within the first preset time length, it means that there is still a large pressure difference on both sides of the contact end of the relay, and the contact end of the relay is in a disconnected state.

[0082] Step S202: Determine that the health detection result of the relay is abnormal closing.

[0083] Step S203: Obtain the contact resistance value according to the contact pressure difference, and determine whether the contact resistance value is less than the preset resistance threshold. If the contact resistance value is greater than or equal to the preset resistance threshold, execute step S204; if the contact resistance value is less than the preset resistance threshold, execute step S205.

[0084] As an example, the current flowing through the contact end of the relay is sampled to obtain the sampled current value, and the contact resistance value can be expressed as R=△V / I1; wherein △V represents the contact pressure difference, and I1 represents the sampled current value.

[0085] As an example, the preset resistance value is used to represent the resistance value of the relay when it is normally turned on. If the contact resistance value of the contact end of the relay is greater than the preset resistance value, it means that the contact end of the relay may be worn or the contact is not tight enough.

[0086] Step S204: determining that the health detection result of the relay is abnormal contact wear.

[0087] Step S205: Obtain the conduction response time according to the sending time and the changing time of the conduction control signal, and determine whether the conduction response time is less than the second preset time. If the conduction response time is greater than or equal to the second preset time, execute step S206; if the conduction response time is less than the second preset time, execute step S207;

[0088] As an example, combining Figure 4 , ON represents the conduction control signal, T1 is the sending time of the conduction control signal, and T2 is the change time of the relay responding to the conduction control signal, that is, the relay closing time. Then the conduction response time can be expressed as △T1=T2-T1.

[0089] Step S206: Determine that the health detection result of the relay is a closing timeout abnormality.

[0090] Step S207: Determine that the health detection result of the relay is normal.

[0091] As an example, the second preset time is a time threshold for the normal response speed of the relay. If the on-response time is greater than or equal to the second preset time, that is, the on-control signal is sent for more than the second preset time, but the relay is not closed, the relay closing timeout occurs.

[0092] In the above implementation, first, by setting the first preset duration and the first preset pressure difference threshold, the relay contact pressure difference is detected within the time window after the conduction control signal is sent. If the contact pressure difference on both sides of the contact end is too large, the relay may have a closing fault. Secondly, after the relay is closed normally, the contact resistance value is calculated using the contact pressure difference, and compared with the preset resistance threshold to determine whether the contact is worn, which can further identify the wear problem of the contact end of the relay caused by long-term use or environmental factors. Finally, the conduction response duration is calculated according to the sending time and change time of the conduction control signal, and compared with the second preset duration to evaluate the response speed of the relay. It can detect whether the relay can respond in time after receiving the conduction control signal, thereby determining whether the relay has a closing timeout abnormality. In this way, by performing a health detection on the relay, the relay can control the load capacitor to stably connect to the power system, thereby ensuring the normal operation of the smart capacitor.

[0093] Reference Figure 5 In some embodiments, the control signal is a disconnection control signal, and step S104 may include steps S301 to S305, which are described in detail below.

[0094] Step S301: within a third preset time period from the moment of sending the disconnect control signal, determine whether the contact pressure difference is greater than the second preset pressure difference threshold. If the contact pressure difference is less than or equal to the second preset pressure difference threshold, execute step S302; if the contact pressure difference is greater than the second preset pressure difference threshold, execute step S303;

[0095] The second preset voltage difference threshold is a voltage difference threshold for judging whether the contact end is normally disconnected. Under normal circumstances, when the contact end of the relay is disconnected, its contact voltage difference changes from zero to close to the output voltage of the voltage source. Therefore, the second preset voltage difference threshold can be set near the output voltage of the voltage source and less than the output voltage of the voltage source, so as to identify the state of the contact end of the relay changing from on to off.

[0096] Among them, the third preset time length is a preset time window, which is used to continuously detect the contact pressure difference within the time window after sending the disconnect control signal. If the contact pressure difference is greater than the second preset pressure difference threshold within the third preset time length, it means that the contact end of the relay has been normally disconnected and closed; if the contact pressure difference is still less than the third preset pressure difference threshold within the third preset time length, it means that the contact end of the relay is in the on state, that is, the relay cannot be disconnected normally.

[0097] Step S302: Determine that the health detection result of the relay is disconnection abnormality.

[0098] Step S303: Obtain the disconnection response duration according to the sending time and the change time of the disconnection control signal, and determine whether the disconnection response duration is less than the fourth preset duration. If the disconnection response duration is greater than or equal to the fourth preset duration, execute step S304; if the disconnection response duration is less than the fourth preset duration, execute step S305.

[0099] As an example, combining Figure 4 , OFF represents the disconnection control signal, T3 is the sending time of the disconnection control signal, and T4 is the change time of the relay responding to the disconnection control signal, that is, the relay disconnection time. Then the disconnection response time can be expressed as △T2=T4-T3.

[0100] Step S304: Determine whether the relay health detection result is an opening timeout abnormality.

[0101] Step S305: Determine whether the relay health detection result is disconnection normal.

[0102] In the above implementation, first, by setting the third preset duration and the second preset pressure difference threshold, the relay contact pressure difference is detected within the time window after the disconnection control signal is sent to identify whether the relay disconnection is abnormal, that is, whether the voltage difference across the contact fails to rise normally to the second preset pressure difference threshold, so as to promptly discover the possible disconnection fault of the relay. Secondly, the disconnection response duration is calculated by the sending time and the change time of the disconnection control signal, and compared with the fourth preset duration to evaluate the disconnection response speed of the relay, so as to determine whether there is a timeout abnormality in the opening of the switch. In this way, by performing a health detection on the relay, the relay can control the load capacitor to stably cut out of the power system.

[0103] As a further implementation of the health detection method of the smart capacitor, step S105 can obtain the health detection result of the load capacitor according to the first temperature value, the second temperature value, the actual current value and the rated current value.

[0104] In the above implementation, firstly, by obtaining the first temperature value inside the load capacitor in the smart capacitor and the second temperature value of the loop where the load capacitor is located, the working environment temperature of the load capacitor is monitored, which helps to promptly discover the risk of performance degradation or damage to the load capacitor due to overheating. Secondly, by sampling the current in the loop where the load capacitor is located, the actual current value is obtained and compared with the rated current value of the load capacitor, so as to evaluate the working load state of the load capacitor and determine whether it is in overload operation, thereby effectively avoiding the shortening of the capacitor life or sudden failure due to long-term overload. In this way, combined with the first temperature value, the second temperature value, the actual current value and the rated current value, the health state of the load capacitor can be comprehensively evaluated, thereby achieving a more comprehensive detection of the health of the smart capacitor.

[0105] In some embodiments, as a further implementation of the health detection method for smart capacitors, the health detection method for smart capacitors also includes a method for obtaining the rated current value of the load capacitance. The acquisition method may include steps S4031-S4033, which are described in detail below.

[0106] Step S4031: sampling the voltage source of the loop where the load capacitor is located to obtain the power supply frequency and the output voltage.

[0107] Step S4032: Obtain the rated capacitance of the load capacitor.

[0108] The rated capacitance is the factory setting parameter of the load capacitance.

[0109] Step S4033: Obtain the rated current value of the load capacitor according to the power frequency, the output voltage and the rated capacitance.

[0110] As an example, the rated current value of the load capacitor can be expressed as In=2πfCU; wherein f represents the power supply frequency, C represents the rated capacitance, and U represents the output voltage of the voltage source.

[0111] In the above implementation, the rated current value of the load capacitor is calculated by using the power supply frequency and output voltage obtained in real time, so that the load capacitor has a matching rated current value under different working conditions, avoiding misjudgment caused by using a fixed rated current value.

[0112] In some embodiments, step S404 may include steps S4041 to S4043, which are described in detail below.

[0113] Step S4041: Determine whether the difference between the actual current value and the rated current value is greater than the preset error value, and compare the first temperature value and the second temperature value with the preset temperature threshold value. If the difference between the actual current value and the rated current value is greater than the preset error value or the first temperature value is greater than the preset temperature threshold value or the second temperature value is greater than the preset temperature threshold value, then execute step S4042; if the difference between the actual current value and the rated current value is less than the preset error value and the first temperature value and the second temperature value are both less than or equal to the preset temperature threshold value, then execute step S4043.

[0114] Step S4042: Determine that the health detection result of the load capacitor is abnormal.

[0115] Step S4043: determining that the health detection result of the load capacitor is normal.

[0116] As an example, when judging whether the difference between the actual current value and the rated current value is greater than the preset error value, the absolute value of the difference between the actual current value and the rated current value can be taken for comparison. For example, the difference between the actual current value and the rated current value can be expressed as △I=|In-I1|; wherein In represents the actual current value and I1 represents the rated current value.

[0117] Among them, the abnormality of the health test result of the load capacitor may be due to abnormalities such as aging of the load capacitor, or it may be due to excessively high harmonics of the voltage source causing the abnormal working state of the load capacitor.

[0118] As an example, since there is an electrical connection between the relay and the load capacitor and they are connected in series, there is a certain correlation between the first temperature value and the second temperature value sampled by the two. For example, if the first temperature value and the second temperature value rise at the same time and are both greater than the preset temperature threshold, it may be due to the excessive harmonics of the voltage source that cause the temperature of the relay and the load capacitor to rise synchronously, and the health detection result may be that the voltage source harmonics are too high. If only the first temperature value is greater than the preset temperature threshold, it may be due to the load capacitor itself. The health detection result may be that the load capacitor is abnormal.

[0119] In the above implementation, firstly, by comparing the difference between the actual current value and the rated current value and the preset error value as the judgment standard to evaluate whether the current performance of the load capacitor in the working state meets expectations, the situation where the current deviation is too large can be effectively identified. Secondly, since temperature is an important factor affecting the performance and service life of the load capacitor, it is determined whether the first temperature value and the second temperature value are both less than or equal to the preset temperature threshold value to ensure that the working environment temperature of the load capacitor is within a safe range. In this way, the health detection result of the load capacitor obtained by combining current and temperature is more comprehensive.

[0120] Reference Figure 6 In a second aspect, in one embodiment, the present application provides a health detection device for a smart capacitor, comprising a voltage sampling circuit 1 and a controller 2. The voltage sampling circuit 1 is used to obtain a first voltage signal and a second voltage signal at a contact end of a relay in the smart capacitor. The controller 2 is connected to the voltage sampling circuit 1, and is used to obtain a health detection result of the relay of the smart capacitor according to the first voltage signal and the second voltage signal. K1 represents a relay.

[0121] In the above implementation, the first voltage signal and the second voltage signal on both sides of the contact end are sampled by the voltage sampling circuit 1, and the first voltage signal and the second voltage signal are analyzed by the controller 2 to obtain the health detection result of the relay. Since the state of the relay is closely related to the working state of the smart capacitor, the health detection of the smart capacitor is realized.

[0122] In some embodiments, the contact end includes a first contact and a second contact, and the voltage sampling circuit 1 includes a first voltage dividing subcircuit for collecting a first voltage signal and a second voltage dividing subcircuit for collecting a second voltage signal.

[0123] The first voltage dividing subcircuit includes a first resistor R1 and a second resistor R2. The first resistor R1 has a first end connected to the first contact, and a second end connected to a first end of the second resistor R2 and the controller 2. The second end of the second resistor R2 is grounded.

[0124] The second voltage dividing subcircuit includes a third resistor R3 and a fourth resistor. The first end of the third resistor R3 is connected to the second contact, and the second end is connected to the first end of the fourth resistor and the controller 2. The second end of the fourth resistor is grounded.

[0125] As an example, the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor can be set according to actual conditions so that the voltage at the contact end after voltage division does not exceed the range of the controller 2 to avoid damage to the controller 2.

[0126] As an example, since the first contact is electrically connected to the voltage source, the voltage of the output signal of the voltage source can be calculated by combining the resistance values ​​of the first resistor R1 and the second resistor R2 with the first divided voltage signal obtained by dividing the first resistor R1 and the second resistor R2.

[0127] As a further implementation of the health detection device of the smart capacitor, the health detection device of the smart capacitor also includes a temperature detection circuit 3 and a current detection circuit 4. Among them, the temperature detection circuit 3 is used to obtain the first temperature value inside the load capacitor in the smart capacitor and the second temperature value of the loop where the load capacitor is located. The current detection circuit 4 is used to sample the current in the loop where the load capacitor is located to obtain the actual current value. The controller 2 is connected to the temperature detection circuit 3 and the current detection circuit 4, and is used to obtain the rated current value of the load capacitor, and obtain the health detection result of the load capacitor based on the first temperature value, the second temperature value, the actual current value and the rated current value.

[0128] As an example, the health detection device of the smart capacitor further includes a communication circuit 5, such as an RS485 communication module, for sending the health detection result to the management terminal so as to perform technical processing when an abnormality occurs in the smart capacitor.

[0129] In a third aspect, in one embodiment, the present application provides a smart capacitor, including: a voltage source, a drive control circuit, a relay, a load capacitor, and a health monitoring device for the smart capacitor.

[0130] The contact end of the relay is connected in series with the voltage source, the load capacitor and the current detection circuit 4, and the coil end is connected with the drive control circuit, so as to control the connection and disconnection of the load capacitor.

[0131] The controller 2 is connected to the voltage sampling circuit 1, the current detection circuit 4, the temperature detection circuit 3 and the drive control circuit, and is used to send a control signal to the drive control circuit to control the on and off of the relay through the drive control circuit, and obtain the health detection result of the smart capacitor according to the first voltage signal, the second voltage signal, the first temperature value, the second temperature value, the actual current value and the rated current value.

[0132] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0133] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.

[0134] The above are only preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A method for detecting the health of a smart capacitor, wherein the smart capacitor comprises a relay, a load capacitor and a controller, characterized in that: include: Respectively obtaining a first voltage signal and a second voltage signal at both ends of a contact of a relay in the intelligent capacitor; Sending a control signal to the relay to control the contact end of the relay to be turned on or off, and recording the sending time of the control signal; Obtaining a contact pressure difference according to the first voltage signal and the second voltage signal, and recording a change time of the contact pressure difference; Acquiring temperature information and current information of the load capacitance of the smart capacitor; A health detection result of the smart capacitor is obtained according to at least one of the temperature information, the current information, the contact pressure difference, the sending time and the changing time.

2. The method for detecting the health of a smart capacitor according to claim 1, characterized in that: The control signal is a conduction control signal, and a health detection result of the smart capacitor is obtained according to at least one of the temperature information, the current information, the contact pressure difference, the sending time, and the changing time, including: Within a first preset time period from the moment when the conduction control signal is sent, determining whether the contact pressure difference is less than a first preset pressure difference threshold; If the contact pressure difference is greater than or equal to the first preset pressure difference threshold, determining that the health detection result of the relay is a closing abnormality; If the contact pressure difference is less than the first preset pressure difference threshold, a contact resistance value is obtained according to the contact pressure difference, and it is determined whether the contact resistance value is less than a preset resistance threshold; If the contact resistance value is greater than or equal to the preset resistance threshold, it is determined that the health detection result of the relay is abnormal contact wear; If the contact resistance value is less than the preset resistance threshold, the conduction response time is obtained according to the sending time of the conduction control signal and the change time, and it is determined whether the conduction response time is less than a second preset time; If the conduction response time is greater than or equal to the second preset time, determining that the health detection result of the relay is a closing timeout abnormality; If the conduction response time is less than the second preset time, it is determined that the health detection result of the relay is operating normally.

3. The method for detecting the health of a smart capacitor according to claim 2, characterized in that: The control signal is a disconnection control signal, and a health detection result of the relay of the smart capacitor is obtained according to the contact pressure difference, the sending time and the changing time, including: Within a third preset time period from the moment when the disconnection control signal is sent, determining whether the contact pressure difference is greater than a second preset pressure difference threshold; If the contact pressure difference is less than or equal to the second preset pressure difference threshold, determining that the health detection result of the relay is disconnection abnormality; If the contact pressure difference is greater than the second preset pressure difference threshold, the disconnection response time is obtained according to the sending time of the disconnection control signal and the change time, and it is determined whether the disconnection response time is less than a fourth preset time; If the disconnection response time is greater than or equal to the fourth preset time, determining that the health detection result of the relay is a disconnection timeout abnormality; If the disconnection response time is less than the fourth preset time, it is determined that the health detection result of the relay is normal disconnection.

4. The method for detecting the health of a smart capacitor according to claim 1, characterized in that: The temperature information includes a first temperature value inside the load capacitor in the smart capacitor and a second temperature value of the loop where the load capacitor is located; the current information includes a rated current value of the load capacitor and an actual current value obtained by sampling the current of the loop where the load capacitor is located; The obtaining of the health detection result of the smart capacitor according to at least one of the temperature information, the current information, the contact pressure difference, the sending time and the changing time also includes: A health detection result of the load capacitor is obtained according to the first temperature value, the second temperature value, the actual current value and the rated current value.

5. The method for detecting the health of a smart capacitor according to claim 4, characterized in that: Also included is a method for obtaining the rated current value of the load capacitor, the method comprising: Sampling the voltage source of the loop where the load capacitor is located to obtain the power supply frequency and the output voltage; Obtaining the rated capacitance of the load capacitor; The rated current value of the load capacitor is obtained according to the power supply frequency, the output voltage and the rated capacitance.

6. The method for detecting the health of a smart capacitor according to claim 4, characterized in that: The obtaining a health detection result of the load capacitor according to the first temperature value, the second temperature value, the actual current value and the rated current value includes: Determine whether the difference between the actual current value and the rated current value is greater than a preset error value, and compare the first temperature value and the second temperature value with preset temperature thresholds respectively; If the difference between the actual current value and the rated current value is greater than the preset error value or the first temperature value is greater than the preset temperature threshold or the second temperature value is greater than the preset temperature threshold, then the health detection result of the load capacitor is determined to be abnormal; If the difference between the actual current value and the rated current value is less than the preset error value and the first temperature value and the second temperature value are both less than or equal to the preset temperature threshold, it is determined that the health detection result of the load capacitor is normal.

7. A health detection device for a smart capacitor, characterized in that: include: A voltage sampling circuit (1) is used to obtain a first voltage signal and a second voltage signal of a contact end of a relay in the smart capacitor; A controller (2) is connected to the voltage sampling circuit (1) and is used to obtain a health detection result of the smart capacitor according to the first voltage signal and the second voltage signal.

8. The health detection device of the smart capacitor according to claim 7, characterized in that: The contact end comprises a first contact and a second contact, and the voltage sampling circuit (1) comprises a first voltage dividing subcircuit for collecting the first voltage signal and a second voltage dividing subcircuit for collecting the second voltage signal; The first voltage dividing subcircuit comprises a first resistor (R1) and a second resistor (R2); The first end of the first resistor (R1) is connected to the first contact, and the second end is connected to the first end of the second resistor (R2) and the controller (2); the second end of the second resistor (R2) is grounded; The second voltage dividing subcircuit includes a third resistor (R3) and a fourth resistor; The first end of the third resistor (R3) is connected to the second contact, and the second end is connected to the first end of the fourth resistor and the controller (2); the second end of the fourth resistor is grounded.

9. The health detection device of the smart capacitor according to claim 7, characterized in that: It also includes a temperature detection circuit (3) and a current detection circuit (4); The temperature detection circuit (3) is used to obtain a first temperature value inside a load capacitor in the intelligent capacitor and a second temperature value of a loop where the load capacitor is located; The current detection circuit (4) is used to sample the current in the loop where the load capacitor is located to obtain an actual current value; The controller (2) is connected to the temperature detection circuit (3) and the current detection circuit (4) to obtain the rated current value of the load capacitor, and obtain a health detection result of the load capacitor based on the first temperature value, the second temperature value, the actual current value and the rated current value.

10. A smart capacitor, characterized in that: include: A voltage source, a drive control circuit, a relay, a load capacitor, and a health monitoring device for a smart capacitor as claimed in claim 9; The contact end of the relay is connected in series with the voltage source, the load capacitor and the current detection circuit (4), and the coil end is connected with the drive control circuit, so as to control the connection and disconnection of the load capacitor; The controller (2) is connected to the voltage sampling circuit (1), the current detection circuit (4), the temperature detection circuit (3) and the drive control circuit, and is used to send a control signal to the drive control circuit to control the on and off of the relay through the drive control circuit, and obtain a health detection result of the smart capacitor according to the first voltage signal, the second voltage signal, the first temperature value, the second temperature value, the actual current value and the rated current value.

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