Direct current leakage current sensor and energy storage system insulation state monitoring method

Abstract

The invention discloses a direct current leakage current sensor and an energy storage system insulation state monitoring method. The direct current leakage current sensor comprises a duplex winding magnetic ring, a signal processing circuit and a leakage current alarm module. When leakage current exists on the direct-current side of the energy storage system, the duplex-winding magnetic ring induces a leakage current signal of the direct-current side of the energy storage system, the signal processing circuit processes the leakage current signal to generate a voltage signal enabling the duplex-winding magnetic ring to keep a zero magnetic flux state, and the leakage current alarm module processes and converts the voltage signal. The direct current leakage current sensor is based on a magnetic modulation technology, and can judge the insulation state of the energy storage system by monitoring the magnitude of the leakage current of the direct current side of the energy storage system, so as to solve the problems of poor effect, low precision and poor reliability of monitoring the insulation state by using insulation impedance traditionally. Electric leakage monitoring on the direct current side of the energy storage battery is realized, early warning is performed in advance, and the possibility of electrical fire of the energy storage system is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of insulation monitoring of energy storage systems, and in particular to a direct current leakage current sensor and an insulation state monitoring method of an energy storage system. Background Art

[0002] With the rapid development of renewable energy and the continuous increase in electricity demand, energy storage systems play an increasingly important role in modern power systems. Energy storage systems can not only balance electricity supply and demand, but also improve the reliability and stability of power systems. In these energy storage systems, various energy storage technologies such as lithium-ion batteries, lead-acid batteries and supercapacitors are widely used. Energy storage systems are widely used in power peak regulation, load regulation, backup power supply and power quality control, and the safety and reliability of their operation are particularly important.

[0003] Since energy storage systems often operate under high voltage and high current conditions, their insulation status is directly related to the safety of the system. If there is a problem with the insulation status of the energy storage system, such as insulation damage or aging, leakage current may be generated, which will not only cause energy loss, but also may bring safety hazards such as electric shock and fire. Therefore, insulation status monitoring of energy storage systems, especially leakage current detection, is one of the key means to ensure the safe operation of the system.

[0004] Because direct current has no alternating electric field, traditional leakage current transformers cannot detect direct current leakage current, resulting in poor monitoring of the insulation status of the energy storage system, low accuracy and poor reliability. Summary of the invention

[0005] The embodiment of the present invention provides a load forecasting method and system for a regional integrated energy system, so as to solve the existing problems.

[0006] An embodiment of the present invention provides a DC leakage current sensor, characterized in that the DC leakage current sensor is connected to the DC side of the energy storage system, and the DC leakage current sensor includes a double-winding magnetic ring, a signal processing circuit and a leakage current alarm module connected in sequence; When there is leakage current on the DC side of the energy storage system, the dual-winding magnetic ring senses the leakage current signal on the DC side of the energy storage system, the signal processing circuit processes the leakage current signal to generate a voltage signal that keeps the dual-winding magnetic ring in a zero flux state, and the leakage current alarm module processes and converts the voltage signal to obtain DC leakage current information on the DC side of the energy storage system and issues an alarm.

[0007] Furthermore, the double-winding magnetic ring comprises a magnetic core made of a high magnetic permeability material and a coil wound on the magnetic core and composed of two groups of multiple turns of conducting wire; The coil includes an excitation coil and a demodulation coil.

[0008] Furthermore, the signal processing circuit includes a square wave voltage source excitation circuit, a square wave positive and negative half-wave effective value difference circuit, and a zero adjustment integration circuit which are connected in sequence; The square wave voltage source excitation circuit outputs a corresponding voltage signal according to the leakage current signal. The voltage signal is processed by the square wave positive and negative half-wave effective value difference circuit to obtain a DC component. The DC component is sent to the zero adjustment integration circuit to form an electromotive force proportional to the leakage current signal. The electromotive force is applied to both ends of the coil of the double-winding magnetic ring to balance the magnetic field generated by the DC leakage current, so that the double-winding magnetic ring maintains a zero flux state.

[0009] Furthermore, the signal processing circuit also includes an analog-to-digital converter connected to the zero-adjusting integration circuit; The analog-to-digital converter converts the feedback signal output by the zero-adjusting integration circuit from an analog signal into a digital signal, and then inputs the digital signal into the leakage current alarm module.

[0010] Further, the leakage current alarm module includes a single chip microcomputer and a leakage current display unit connected in sequence; The single chip microcomputer processes and converts the digital signal to obtain DC leakage current information of the DC side of the energy storage system. The leakage current display unit displays the DC leakage current information, and the DC leakage current information includes the direction and magnitude of the DC leakage current.

[0011] Furthermore, the leakage current alarm module further includes an alarm unit connected to the single chip microcomputer; The single chip microcomputer compares the magnitude of the DC leakage current with a set current threshold value, and if the magnitude of the DC leakage current exceeds the current threshold value, sends a control signal to the alarm unit, and the alarm unit sends an alarm signal based on the control signal.

[0012] Furthermore, the alarm unit includes a drive circuit, and a buzzer and an indicator light respectively connected to the drive circuit; The driving circuit turns on the power of the buzzer and the indicator light based on the control signal, the buzzer emits an alarm sound, and the indicator light emits a visual alarm signal with a color and / or flashing frequency corresponding to the control signal.

[0013] Furthermore, when there is no leakage current on the DC side of the energy storage system, the double-winding magnetic ring maintains a zero magnetic flux state.

[0014] Accordingly, an embodiment of the present invention provides a method for monitoring insulation status of an energy storage system, comprising: When there is leakage current on the DC side of the energy storage system, the leakage current signal on the DC side of the energy storage system is sensed by the double-winding magnetic ring of the DC leakage current sensor; The leakage current signal is processed by the signal processing circuit of the DC leakage current sensor to generate a voltage signal that keeps the double-winding magnetic ring in a zero flux state; The voltage signal is processed and converted by the leakage current alarm module of the DC leakage current sensor to obtain the DC leakage current information of the DC side of the energy storage system and issue an alarm; The DC leakage current sensor is the DC leakage current sensor according to any one of claims 1 to 8.

[0015] Furthermore, the double-winding magnetic ring comprises a magnetic core made of a high magnetic permeability material and a coil wound on the magnetic core and composed of two groups of multiple turns of conducting wire; The coil includes an excitation coil and a demodulation coil.

[0016] Since the DC leakage current sensor in the embodiment of the present invention includes a double-winding magnetic ring, a signal processing circuit and a leakage current alarm module connected in sequence; when there is leakage current on the DC side of the energy storage system, the double-winding magnetic ring senses the leakage current signal on the DC side of the energy storage system, the signal processing circuit processes the leakage current signal to generate a voltage signal that keeps the double-winding magnetic ring in a zero magnetic flux state, and the leakage current alarm module processes and converts the voltage signal to obtain DC leakage current information on the DC side of the energy storage system and issues an alarm, the DC leakage current sensor is based on magnetic modulation technology and can judge the insulation state of the energy storage system by monitoring the leakage current on the DC side of the energy storage system, so as to solve the problems of poor effect, low precision and poor reliability of traditional insulation state monitoring using insulation impedance, realize leakage monitoring on the DC side of the energy storage battery, and issue an early warning, thereby greatly reducing the possibility of electrical fires in the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. 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 accompanying drawings: Figure 1 A schematic diagram of the structure of a DC leakage current sensor provided by an embodiment of the present invention; Figure 2 A schematic diagram of a double winding of an induction coil of a DC leakage current sensor provided by an embodiment of the present invention; Figure 3 A schematic diagram of the overall working principle of a leakage current sensor of a DC leakage current sensor provided by an embodiment of the present invention; Figure 4A waveform diagram of an excitation winding voltage and an induction winding voltage when there is leakage current in a DC leakage current sensor provided by an embodiment of the present invention; Figure 5 A schematic flow chart of a method for monitoring insulation status of an energy storage system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] 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 invention can be combined with each other without conflict.

[0019] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0020] Embodiment 1: Figure 1 A schematic diagram of the structure of a DC leakage current sensor provided by an embodiment of the present invention. The DC leakage current sensor is connected to the DC side of the energy storage system, and the DC leakage current sensor includes a double-winding magnetic ring, a signal processing circuit and a leakage current alarm module connected in sequence; When there is leakage current on the DC side of the energy storage system, the dual-winding magnetic ring senses the leakage current signal on the DC side of the energy storage system. The signal processing circuit processes the leakage current signal to generate a voltage signal that keeps the dual-winding magnetic ring in a zero flux state. The leakage current alarm module processes and converts the voltage signal to obtain the DC leakage current information on the DC side of the energy storage system and issues an alarm.

[0021] The leakage current is the vector difference caused by the current imbalance. Generally, the leakage current is relatively small, at the milliampere level. Since direct current has no alternating electric field, the traditional leakage current transformer cannot detect the DC leakage current. In the embodiment of the present invention, a DC leakage current sensor is proposed, which can also be called a magnetic modulation current transformer. Different from the traditional leakage current transformer, the DC leakage current sensor in the embodiment of the present invention is based on magnetic modulation technology. It can judge the insulation state of the energy storage system by monitoring the leakage current on the DC side of the energy storage system, so as to solve the problem of poor effect, low accuracy and poor reliability of the traditional use of insulation impedance to monitor the insulation state, realize the leakage monitoring of the DC side of the energy storage battery, and give early warning, which greatly reduces the possibility of electrical fires in the energy storage system. And the DC leakage current sensor provided in the embodiment of the present invention can achieve a measurement accuracy of 10 microamperes when used for insulation state monitoring of the energy storage system.

[0022] When there is no leakage current on the DC side of the energy storage system, the dual-winding magnetic ring maintains a zero flux state; when there is leakage current on the DC side of the energy storage system, the dual-winding magnetic ring will generate a DC bias magnetic field, and the magnetic flux is not zero at this time. The signal processing circuit processes the voltage signal applied to the dual-winding magnetic ring, which can balance the magnetic field generated by the DC leakage current, so that the dual-winding magnetic ring can maintain a zero flux state again. Therefore, by detecting the size of the voltage signal applied by the signal processing circuit and converting it, the DC leakage current information on the DC side of the energy storage system can be obtained. The DC leakage current information can include the direction and size of the DC leakage current.

[0023] In one implementation, Figure 2 As shown, the double-winding magnetic ring includes a magnetic core made of a high magnetic permeability material and a coil composed of two groups of several turns of wire wound on the magnetic core; the coil includes an excitation coil and a demodulation coil. In other words, the double-winding magnetic ring includes a magnetic core and two groups of several turns of wire wound on the coil, and the positive and negative busbars on the DC side simultaneously pass through the center hole of the magnetic ring of the DC leakage inductance sensor. When there is a leakage current on the DC side of the energy storage system, the leakage current generates an electromagnetic induction signal in the double-winding magnetic ring. The primary winding of the double-winding magnetic ring is connected to the square wave excitation circuit, and the secondary winding is connected to the demodulation circuit. The double-winding magnetic ring can also include a feedback winding for providing a feedback signal to achieve control and protection of the motor or circuit.

[0024] In one example, the signal processing circuit includes a square wave voltage source excitation circuit (also called a square wave stimulation circuit), a square wave positive and negative half-wave effective value difference circuit (also called a square wave effective value difference circuit), and a zero adjustment integration circuit connected in sequence; the square wave voltage source excitation circuit outputs a corresponding voltage signal according to the leakage current signal, and the voltage signal is processed by the square wave positive and negative half-wave effective value difference circuit to obtain a DC component, and the DC component is sent to the zero adjustment integration circuit to form an electromotive force proportional to the leakage current signal. The electromotive force is applied to both ends of the coil of the double-winding magnetic ring to balance the magnetic field generated by the DC leakage current, so that the double-winding magnetic ring maintains a zero flux state.

[0025] In this example, the square wave voltage source excitation circuit sends a continuously oscillating excitation signal to the primary coil (of the double-winding magnetic ring) of the DC leakage current sensor. The excitation signal can be a voltage signal. The voltage signal output by the square wave voltage source excitation circuit is processed by the square wave positive and negative half-wave effective value difference circuit to obtain a DC component, which is then sent to the zero-adjusting integration circuit to form an electromotive force that is proportional to the DC leakage current. The electromotive force applied to both ends of the feedback winding can balance the magnetic field generated by the DC leakage current, so that the magnetic ring maintains a zero flux state. Therefore, by detecting the size of the feedback winding voltage signal after signal processing and converting it, the direction and size of the DC side leakage current of the energy storage system can be obtained.

[0026] The feedback winding voltage signal can be reflected by a demodulated signal or a feedback signal output by a signal processing circuit.

[0027] In one implementation, the signal processing circuit converts the output demodulated signal into a valid analog signal and inputs it into the leakage alarm module.

[0028] In another implementation, the signal processing circuit further includes an analog-to-digital converter connected to the zero-adjusting integration circuit; the analog-to-digital converter converts the feedback signal output by the zero-adjusting integration circuit from an analog signal to a digital signal, and then inputs the digital signal into the leakage current alarm module.

[0029] See also Figure 3 , the DC leakage current sensor is connected to the square wave voltage source excitation circuit in the signal processing circuit. The DC leakage current sensor is specifically a dual-winding current transformer, and the square wave voltage source excitation circuit can be specifically a square wave oscillator. The DC leakage current sensor is connected to the DC bus to be measured, that is, the DC side of the energy storage system. When there is leakage current on the DC side of the energy storage system, the square wave oscillator uses the inductance effect of the detection coil to generate a square wave signal. When there is DC bias in the magnetic core, an electromotive force is generated on the detection coil to distort the waveform of the output voltage signal of the excitation circuit, and the distorted square wave signal, that is, the voltage signal, is sent to the subsequent circuit for further processing. The square wave positive and negative half-wave effective value difference circuit, as the subsequent circuit of the square wave oscillator, can be a filter, specifically a wireless gain filter, which can obtain a DC component by filtering out the high-frequency noise in the voltage signal. The zero-adjusting integration circuit can zero-adjust and amplify the filtered signal, that is, the DC component, to obtain an output signal. At the same time, the output signal is also a feedback signal that can balance the DC bias. Figure 2 In the invention, the zero adjustment integral circuit includes a zero point adjustment circuit, a proportional amplifier and a low pass filter connected in sequence, and the low pass filter can realize voltage output. The analog-to-digital converter can convert the amplified analog signal into a digital signal and input it into the leakage alarm module.

[0030] For example, Figure 3 In the embodiment, the leakage current alarm module includes a single chip microcomputer and a leakage current display unit connected in sequence; optionally, the leakage current alarm module also includes an alarm unit connected to the single chip microcomputer, also called an alarm device.

[0031] In the above implementation, the signal processing circuit converts the output demodulated signal into a valid analog signal and inputs it into the single chip microcomputer, or the analog-to-digital converter converts the amplified analog signal into a digital signal for processing by the single chip microcomputer.

[0032] The single chip microcomputer processes and converts the digital signal to obtain the DC leakage current information of the DC side of the energy storage system. The leakage current display unit displays the DC leakage current information, for example, it can display the direction and magnitude of the DC leakage current.

[0033] If the leakage current alarm module includes an alarm device, the single-chip microcomputer can also compare the magnitude of the DC leakage current with the set current threshold. If the magnitude of the DC leakage current exceeds the current threshold, a control signal is sent to the alarm unit, and the alarm unit sends an alarm signal based on the control signal. The set current threshold is used as a preset action threshold. In this example, the single-chip microcomputer can calculate the effective value of the DC leakage current and display it on the leakage current display unit. When the effective value of the DC leakage current reaches the preset action threshold, an action signal is output to the alarm unit to send an alarm.

[0034] In one implementation, the single-chip microcomputer is connected to the signal processing circuit, the leakage current display unit, and the alarm unit through the I / O (Input / Output) port. The leakage current display unit can be a liquid crystal display that can display the measured DC leakage current information in real time. The single-chip microcomputer is responsible for receiving the digital signal from the sensor, comparing it with the measured DC leakage current value according to the preset action threshold, and triggering the alarm unit if the measured value exceeds the preset threshold.

[0035] The alarm unit may include a drive circuit, and a buzzer and an indicator light connected to the drive circuit respectively; the drive circuit turns on the power of the buzzer and the indicator light based on the control signal, the buzzer emits an alarm sound, and the indicator light emits a visual alarm signal of a color and / or flashing frequency corresponding to the control signal. When the alarm unit is triggered, the single-chip microcomputer may send a control signal to the drive circuit, and the drive circuit is responsible for controlling the working state of the buzzer and the indicator light, receiving the control signal from the single-chip microcomputer, and turning on or off the power of the buzzer and the indicator light according to the control signal. The buzzer is used to emit an audible alarm signal, and when an abnormal situation is detected, the buzzer will emit a preset alarm sound. The indicator light is used to emit a visual alarm signal, and when the alarm condition is triggered, the indicator light will light up. The indication indicates different alarm states or severity levels with different colors or flashing frequencies.

[0036] In an embodiment of the present invention, when there is no leakage current on the DC side of the energy storage system, the magnetic core maintains a zero flux state, the magnetic ring has entered saturation, and the operational amplifier output signal is a square wave signal with symmetric positive and negative half-waves in the excitation cycle. When there is leakage current on the DC side of the energy storage system, the DC leakage current generates a DC bias magnetic field in the magnetic core. At this time, the magnetic flux in the magnetic core is not zero. Since the voltage signal generated on the detection winding is connected to the reverse input terminal of the operational amplifier through a resistor divider, when the DC bias magnetic field is in the same direction as the magnetic field initially generated by the detection coil voltage, the magnetic core reaches magnetic saturation in advance, and when the external magnetic field is opposite to the internal magnetic field, it takes longer for the magnetic core to reach magnetic saturation. Therefore, the operational amplifier outputs a square wave signal. The ratio of the positive and negative half-waves changes during the excitation cycle, and the waveform is distorted and no longer symmetrical. The output voltage signal of the square wave excitation circuit is processed by the square wave effective value difference circuit to obtain a DC component, and then sent to the zero adjustment and integration circuit to form an electromotive force that is proportional to the DC leakage current. The voltage signal applied to both ends of the feedback winding can balance the magnetic field generated by the DC leakage current, so that the magnetic ring maintains a zero flux state. Therefore, by detecting the magnitude of the feedback winding voltage signal after signal processing and converting it, the direction and magnitude of the DC side leakage current of the energy storage system can be obtained. Figure 4 The waveforms of the excitation winding voltage and the induction winding voltage when there is leakage current show that the waveforms are distorted and the effective value of the secondary winding voltage changes. Excitation winding: The excitation winding (also called the excitation winding) is a coil winding that can generate a magnetic field. Induction winding: The winding structure and insulation system in the induction motor are the key to the design. Primary winding and secondary winding: In the transformer, the primary winding is the winding connected to the power supply and receives energy from the power supply; the secondary winding is the winding connected to the load and mainly provides energy to the load. Usually, the wire diameter of the primary winding is thinner, the number of turns is more, and the winding resistance is larger, while the secondary winding is the opposite.

[0037] In an embodiment of the present invention, a DC leakage current sensor for monitoring the insulation status of an energy storage system includes a double-winding magnetic ring based on the magnetic modulation principle, which operates in a deep saturation state and is used to sense DC leakage current; a signal processing circuit for processing and feeding back the sensed leakage current signal, including a square wave voltage source excitation circuit, a square wave positive and negative half-wave effective value difference circuit, a zero adjustment circuit and an integration circuit; a leakage current display and alarm device: processes and converts the signal output by the signal processing circuit, displays the leakage current information, and issues an alarm when the leakage current exceeds a preset value, so that the staff can check it conveniently.

[0038] In the embodiment of the present invention, the DC leakage current sensor for monitoring the insulation status of the energy storage system adopts a dual-coil structure, including a detection winding and a feedback winding. The sensor has a simple structure, high sensitivity, good detection accuracy and stability, can accurately measure the DC tiny leakage current, and realize accurate online monitoring of the insulation status of the DC side of the energy storage system, so as to timely discover and deal with potential safety hazards, provide strong guarantee for the stable operation of the energy storage system, and is suitable for application scenarios involving energy storage systems such as renewable energy power generation.

[0039] The technical solution provided by the embodiment of the present invention can provide a solution for insulation monitoring of an energy storage system and give a timely warning.

[0040] Embodiment 2: Figure 5 A schematic flow chart of a method for monitoring insulation status of an energy storage system provided by an embodiment of the present invention includes the following steps: S501: When there is leakage current on the DC side of the energy storage system, a leakage current signal on the DC side of the energy storage system is sensed by a double-winding magnetic ring of a DC leakage current sensor; S502: Processing the leakage current signal through the signal processing circuit of the DC leakage current sensor to generate a voltage signal that keeps the double-winding magnetic ring in a zero magnetic flux state; S503: Process and convert the voltage signal through the leakage current alarm module of the DC leakage current sensor to obtain the DC leakage current information of the DC side of the energy storage system and issue an alarm.

[0041] The DC leakage current sensor is the DC leakage current sensor of the above embodiment.

[0042] Optionally, the double-winding magnetic ring includes a magnetic core made of a high magnetic permeability material and a coil wound on the magnetic core and composed of two groups of multiple turns of conductive wire; the coil includes an excitation coil and a demodulation coil.

[0043] Optionally, in the above S502, the square wave voltage source excitation circuit in the signal processing circuit outputs a corresponding voltage signal according to the leakage current signal, and the voltage signal is processed by the square wave positive and negative half-wave effective value difference circuit in the signal processing circuit to obtain a DC component. The DC component is sent to the zero adjustment integration circuit in the signal processing circuit to form an electromotive force proportional to the leakage current signal. The electromotive force is applied to both ends of the coil of the double-winding magnetic ring to balance the magnetic field generated by the DC leakage current, so that the double-winding magnetic ring maintains a zero flux state.

[0044] Optionally, the method further includes: converting the feedback signal output by the zero-adjusting integration circuit from an analog signal to a digital signal based on an analog-to-digital converter in the signal processing circuit, and then inputting the digital signal into the leakage current alarm module.

[0045] Optionally, in the above S503, the single chip microcomputer based on the leakage current alarm module processes and converts the digital signal to obtain DC leakage current information on the DC side of the energy storage system, and the leakage current display unit based on the leakage current alarm module displays the DC leakage current information, and the DC leakage current information includes the direction and magnitude of the DC leakage current.

[0046] Optionally, in the above S503, the microcontroller based on the leakage current alarm module compares the magnitude of the DC leakage current with the set current threshold. If the magnitude of the DC leakage current exceeds the current threshold, a control signal is sent to the alarm unit of the leakage current alarm module, and the alarm unit sends an alarm signal based on the control signal.

[0047] Optionally, in the above S503, the driving circuit in the alarm unit turns on the power of the buzzer and the indicator light in the alarm unit based on the control signal, the buzzer emits an alarm sound, and the indicator light emits a visual alarm signal with a color and / or flashing frequency corresponding to the control signal.

[0048] Optionally, when there is no leakage current on the DC side of the energy storage system, the double-winding magnetic ring maintains a zero flux state.

[0049] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

[0050] The embodiments described in the present invention are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0051] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0052] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0053] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0054] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A DC leakage current sensor, characterized in that: The DC leakage current sensor is used to be connected to the DC side of the energy storage system, and the DC leakage current sensor includes a double-winding magnetic ring, a signal processing circuit and a leakage current alarm module connected in sequence; When there is leakage current on the DC side of the energy storage system, the dual-winding magnetic ring senses the leakage current signal on the DC side of the energy storage system, the signal processing circuit processes the leakage current signal to generate a voltage signal that keeps the dual-winding magnetic ring in a zero flux state, and the leakage current alarm module processes and converts the voltage signal to obtain DC leakage current information on the DC side of the energy storage system and issues an alarm.

2. The sensor according to claim 1, characterized in that The double-winding magnetic ring comprises a magnetic core and a coil wound on the magnetic core and composed of two groups of multiple turns of conducting wire; The two groups of coils consisting of several turns of conducting wires are respectively an excitation coil and a demodulation coil.

3. The sensor according to claim 1 or 2, characterized in that The signal processing circuit includes a square wave voltage source excitation circuit, a square wave positive and negative half-wave effective value difference circuit, and a zero adjustment integration circuit connected in sequence; The square wave voltage source excitation circuit is used to output a corresponding voltage signal according to the leakage current signal. The voltage signal is processed by the square wave positive and negative half-wave effective value difference circuit to obtain a DC component. The DC component is sent to the zero adjustment integration circuit to form an electromotive force proportional to the leakage current signal. The electromotive force is applied to both ends of the coil of the double-winding magnetic ring to balance the magnetic field generated by the DC leakage current, so that the double-winding magnetic ring maintains a zero flux state.

4. The sensor according to claim 3, characterized in that The signal processing circuit also includes an analog-to-digital converter connected to the zero-adjusting integration circuit; The analog-to-digital converter is used to convert the feedback signal output by the zero-adjusting integration circuit from an analog signal into a digital signal, and then input the digital signal into the leakage current alarm module.

5. The sensor according to claim 4, characterized in that The leakage current alarm module includes a single chip microcomputer and a leakage current display unit connected in sequence; The single chip microcomputer is used to process and convert the digital signal to obtain the DC leakage current information of the DC side of the energy storage system; the leakage current display unit is used to display the DC leakage current information, and the DC leakage current information includes the direction and magnitude of the DC leakage current.

6. The sensor according to claim 5, characterized in that The leakage current alarm module also includes an alarm unit connected to the single chip microcomputer; The single chip microcomputer is used to compare the magnitude of the DC leakage current with a set current threshold value, and if the magnitude of the DC leakage current exceeds the current threshold value, send a control signal to the alarm unit; the alarm unit is used to send an alarm signal based on the control signal.

7. The sensor according to claim 6, characterized in that The alarm unit includes a driving circuit, and a buzzer and an indicator light respectively connected to the driving circuit; The driving circuit is used to turn on the power of the buzzer and the indicator light based on the control signal, the buzzer emits an alarm sound, and the indicator light emits a visual alarm signal with a color and / or flashing frequency corresponding to the control signal.

8. The sensor according to claim 1 or 2, characterized in that: When there is no leakage current on the DC side of the energy storage system, the double-winding magnetic ring maintains a zero flux state.

9. A method for monitoring insulation status of an energy storage system, characterized in that: include: When there is leakage current on the DC side of the energy storage system, the leakage current signal on the DC side of the energy storage system is sensed by the double-winding magnetic ring of the DC leakage current sensor; The leakage current signal is processed by the signal processing circuit of the DC leakage current sensor to generate a voltage signal that keeps the double-winding magnetic ring in a zero flux state; The voltage signal is processed and converted by the leakage current alarm module of the DC leakage current sensor to obtain the DC leakage current information of the DC side of the energy storage system and issue an alarm; The DC leakage current sensor is the DC leakage current sensor according to any one of claims 1 to 8.

10. The method according to claim 9, characterized in that The double-winding magnetic ring comprises a magnetic core made of a high magnetic permeability material and a coil wound on the magnetic core and consisting of two groups of multiple turns of conducting wire; The two groups of coils consisting of several turns of conducting wires are respectively an excitation coil and a demodulation coil.

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