Insulation monitoring device and power system used in power system

Abstract

The embodiment of the present invention provides an insulation monitoring device and a power system applied to a power system, wherein the power system includes at least one power electronic converter module, and the insulation monitoring device includes an insulation component, a signal source, an impedance module and a monitoring module, wherein the insulation component is at least partially covered on the power electronic converter module, the signal source is electrically coupled to a circuit node in the power electronic converter module, the impedance module is connected in series between the signal source and the insulation component, and the monitoring module is used to monitor the insulation resistance value of the insulation component, thereby determining the insulation state of the power electronic converter module. Compared with the prior art, the embodiment of the present invention does not require the installation of an additional expensive voltage coupling device during monitoring, and the monitoring cost is low; in addition, the embodiment of the present invention refines the monitoring process to the unit level, and can monitor the insulation state of any power electronic converter module and its internal electrical unit in the power system, which is conducive to improving the reliability of the power system.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of insulation monitoring, and in particular to an insulation monitoring device applied to a power system and a power system. Background Art

[0002] The practicality and high frequency of new power field control devices have brought power electronic converter modules into an era of high frequency, high power density and high efficiency. At the same time, with the development of smart grids, high-power power electronic converter modules have begun to be widely used in power quality control, energy storage, power transmission, and new energy fields such as solar energy and wind power. Therefore, a type of medium-voltage power electronic converter modules will appear on the branch transmission lines in the power system. The medium voltage range is 2.4kV to 69kV. Usually for China, the United States and Europe, the typical values ​​of this medium voltage application are: 10kV, 12.47kV and 20kV respectively. Under the condition of medium voltage power use, the insulation protection of the equipment is the top priority for the safety and reliability of the system.

[0003] Since the power electronic converter module introduces solid insulation, the insulator covers the power electronic circuits and conductors that contain both high-voltage power frequency components and high-frequency pulse width modulation (PWM) square wave components. Therefore, it is particularly important to monitor the insulation condition of each power electronic converter module.

[0004] At present, there are insulation monitoring devices for AC and DC power systems, which can be used to monitor the insulation of medium-voltage frequency conversion systems. The insulation monitoring device requires a set of signal generating devices and microprocessor hosts. The disadvantage is that the signal generating device and the microprocessor host are low-voltage circuits, so an additional voltage coupling device is required to achieve high-low voltage isolation. Since the voltage coupling device is expensive, this inevitably increases the cost of insulation detection. In addition, the insulation monitoring device is used to detect the entire medium-voltage frequency conversion system, and cannot detect the insulation status of the power electronic converter module separately. Summary of the invention

[0005] The embodiments of the present invention provide an insulation monitoring device and a power system to overcome the current technical problems of high insulation detection cost and inability to monitor the insulation state of a power electronic converter module.

[0006] In a first aspect, an embodiment of the present invention provides an insulation monitoring device applied to a power system, the power system comprising at least one power electronic converter module, the insulation monitoring device comprising an insulation component, a signal source, an impedance module and a monitoring module;

[0007] The insulating component is at least partially covered on the power electronic converter module;

[0008] The signal source is electrically coupled to a circuit node in the power electronic converter module;

[0009] The impedance module is connected in series between the signal source and the insulating component;

[0010] The monitoring module is used to monitor the insulation resistance value of the insulation component.

[0011] In one possible design, the insulating component includes a charged body layer, a solid insulating layer and a grounding layer, wherein the solid insulating layer is arranged between the charged body layer and the grounding layer; the charged body layer is arranged on a side of the insulating component close to the power electronic converter module; the grounding layer is arranged on a side of the insulating component away from the power electronic converter module and is grounded.

[0012] In a possible design, the circuit node is a midpoint of a bridge arm in the power electronic converter module, and / or a node on a positive or negative DC bus in the power electronic converter module.

[0013] In one possible design, the circuit node is a circuit node in a converter that provides auxiliary power to the power electronic converter module.

[0014] In a possible design, the voltage waveform of the circuit node contains a DC component.

[0015] In a possible design, the insulation monitoring device further includes a support portion, and the support portion is disposed between the power electronic converter module and the charged body layer so that a gap exists between the power electronic converter module and the charged body layer.

[0016] In a possible design, the support portion is made of insulating material, and the impedance module is disposed inside or outside the support portion.

[0017] In a possible design, the support portion is at least a part of the impedance module.

[0018] In a possible design, the insulation monitoring device further includes an insulating layer, and the insulating layer is arranged between the power electronic converter module and the charged body layer.

[0019] In a possible design, the impedance module includes any one or more of a resistor device, an inductor device, and a capacitor device.

[0020] In a possible design, the impedance module includes at least one LC filtering circuit.

[0021] In a possible design, a plurality of insulating components are included, and an impedance module corresponding to each insulating component is connected in series between a corresponding signal source and the insulating component.

[0022] In one possible design, the power electronic converter module includes a transformer or an inductor, and at least one insulating component at least partially covers at least a portion of the winding of the transformer or the inductor; the impedance module corresponding to the insulating component can be connected in series between any electrical node of the winding and the insulating component, or distributed in series between multiple electrical nodes of the winding and the insulating component.

[0023] In a second aspect, an embodiment of the present invention provides a power system, the power system comprising an insulation monitoring device, and the insulation monitoring device is the insulation monitoring device provided in the first aspect.

[0024] The embodiment of the present invention provides an insulation monitoring device and a power system applied to a power system, the power system includes at least one power electronic converter module, the insulation monitoring device includes an insulation component, a signal source, an impedance module and a monitoring module, wherein the insulation component is at least partially covered on the power electronic converter module, the signal source is electrically coupled to the circuit node in the power electronic converter module, the impedance module is connected in series between the signal source and the insulation component, and the monitoring module is used to monitor the insulation resistance value of the insulation component, so as to determine the insulation state of the power electronic converter module based on the insulation resistance value. Compared with the prior art, the signal source used in the embodiment of the present invention is a circuit node in the power electronic converter module. Since there is no high voltage difference between the signal source and the insulation component, there is no need to install an expensive voltage coupling device in the insulation monitoring process, and the monitoring cost is low; in addition, the embodiment of the present invention refines the insulation monitoring process to the unit level, and can monitor the insulation state of any power electronic converter module and its internal electrical unit in the power system, which is conducive to improving the reliability of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 A schematic diagram of a medium voltage power system architecture based on a medium voltage power supply module provided in an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of the architecture of a medium voltage power supply system provided by an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 1 ;

[0029] Figure 4 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 2 ;

[0030] Figure 5 A schematic diagram of the structure of an impedance module in an insulation monitoring device for a power system provided by an embodiment of the present invention;

[0031] Figure 6 A schematic diagram of the position of a signal source in an insulation monitoring device applied to a power system provided by an embodiment of the present invention;

[0032] Figure 7 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 3 ;

[0033] Figure 8 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 4 ;

[0034] Fig. 9 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 5 ;

[0035] Fig.10 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 6 ;

[0036] Fig.11 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 7 ;

[0037] Fig.12 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 8 . DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of 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.

[0039] The functions that power electronic converters can achieve include: converting power from AC to DC, converting DC to DC, converting DC to AC, converting AC of the same frequency to AC, changing the frequency amplitude of AC, etc.

[0040] In the embodiment of the present invention, the power electronic converter is modularized, and the medium voltage grid input and low voltage and high current output are adapted through the cascading and parallel connection of the power electronic converter modules.

[0041] Please refer to Figure 1 , Figure 1 A schematic diagram of a medium voltage power system architecture based on a medium voltage power supply module is provided in an embodiment of the present invention. Figure 1 In the invention, the power electronic converter module includes a direct current / direct current (DC / DC) module (used to convert direct current into direct current) and an alternating current / direct current (AC / DC) module (used to convert alternating current into direct current). By cascading and paralleling several DC / DC modules and AC / DC modules, the access to the medium voltage power grid and the output of low voltage and high current can be achieved.

[0042] Reference Figure 2 , Figure 2 A schematic diagram of the medium voltage power supply system architecture provided by an embodiment of the present invention. Figure 2 In the embodiment, the power system includes at least one power electronic converter module 210. The input side of the power system is connected to an AC power source, and the output side is connected to a DC bus. In addition, optionally, the power system may also include a converter 220 for providing auxiliary power to the power electronic converter module 210.

[0043] For the above Figure 1 or Figure 2 In the power system shown, the insulation locations that need to be processed usually include: phase-to-phase insulation, module-to-module insulation, insulation between the primary and secondary windings of the high-frequency transformer, and insulation between the medium-voltage side of the auxiliary power supply and the safety extra-low voltage circuit (SELV) on the mains side.

[0044] An embodiment of the present invention provides an insulation monitoring device, which is applied to an electric power system. The electric power system may be Figure 1 The power system shown can also be Figure 2 The power system shown.

[0045] Specifically, refer to Figure 3 , Figure 3A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 1 In an embodiment of the present invention, the insulation monitoring device includes an insulation component 310, a signal source 320, an impedance module 330 and a monitoring module 340. The insulation component 310 is at least partially enclosed in the power electronic converter module 210; the signal source 320 is electrically coupled to a circuit node in the power electronic converter module; the impedance module 330 is connected in series between the signal source 320 and the insulation component 310; and the monitoring module 340 is used to monitor the insulation resistance value of the insulation component 310.

[0046] The insulating component 310 is at least partially covered on the power electronic converter module 210 , which can be understood as the insulating component 310 covering any one or more components in the power electronic converter module 210 .

[0047] Among them, the monitoring module 340 is used to pick up electrical signals from both ends of the impedance module 330, and then based on the preset signal processing circuit and algorithm, the insulation resistance value of the insulation component 310 can be determined, and then according to the insulation resistance value of the insulation component 310, the insulation condition of the above-mentioned power electronic converter module 210 can be determined.

[0048] Considering the compactness of the power system assembly and the maintenance of high power density, while reducing the risk of air discharge under high voltage, the insulation component 310 can adopt a shielded solid insulation component, which is coated on the power electronic converter module 210.

[0049] The power electronic converter module 210 can utilize its own adjustable pulse width modulation (PWM) wave to perform real-time insulation monitoring under normal or specific working conditions (such as light load, standby, sleep, etc.).

[0050] By continuously monitoring and evaluating the insulation condition of the power electronic converter module 210, prompt and rapid warnings can be given based on signals of insulation degradation and increased failure probability, which helps to locate and maintain faults and prevent medium voltage equipment failures, thereby significantly reducing maintenance costs and improving the reliability of the power system.

[0051] That is, in an insulation monitoring device for an electric power system provided in an embodiment of the present invention, the signal source 320 used is a circuit node in the power electronic converter module 210. Since there is no high voltage difference between the signal source 320 and the insulating component 310, there is no need to install an expensive voltage coupling device during the insulation monitoring process, and the monitoring cost is low. In addition, the embodiment of the present invention refines the insulation monitoring process to the unit level, and can monitor the insulation status of any power electronic converter module in the power system, which is beneficial to improving the reliability of the power system.

[0052] Furthermore, in another feasible embodiment of the present invention, the insulation monitoring device may also include a plurality of insulation components 310 , and the impedance module 330 corresponding to each insulation component 310 is connected in series between the corresponding signal source and the insulation component.

[0053] It is understandable that the above insulation monitoring device may have multiple insulation components, multiple signal sources, multiple impedance modules and multiple monitoring modules. Figure 1 or Figure 2 Taking the power system shown as an example, when there are multiple power electronic converter modules that need to be monitored in the power system, multiple insulating components are respectively covered on each power electronic converter module that needs to be monitored; multiple signal sources are respectively electrically coupled to circuit nodes in each power electronic converter module that needs to be monitored, and multiple impedance modules are respectively connected in series between each signal source and the corresponding insulating component; multiple monitoring modules are respectively used to monitor the insulation resistance value of each insulating component, and then the insulation condition of each power electronic converter module that needs to be monitored is determined according to the insulation resistance value of each insulating component.

[0054] That is, an insulation monitoring device applied to an electric power system provided by an embodiment of the present invention adopts multiple insulation components, and the impedance module corresponding to each insulation component is connected in series between the corresponding signal source and the insulation component. It can monitor the insulation status of multiple or all power electronic converter modules in the electric power system, which is beneficial to improving the reliability of the electric power system.

[0055] Further, based on the insulation monitoring device described in the above embodiment, referring to Figure 4 , Figure 4 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 2 In a feasible embodiment of the present invention, the insulating component 310 includes a charged body layer 311, a solid insulating layer 312 and a grounding layer 313, wherein the solid insulating layer 312 is disposed between the charged body layer 311 and the grounding layer 313; the charged body layer 311 is disposed on a side of the insulating component 310 close to the power electronic converter module 210; and the grounding layer 313 is disposed on a side of the insulating component 310 away from the power electronic converter module 210 and is grounded.

[0056] In practical applications, the high voltage stress generated by the power electronic converter module 210 will be applied entirely to the solid insulating layer 312, and the high voltage circuit in the power electronic converter module 210 is shielded by the charged body layer 311, which can prevent the air discharge problem inside the circuit. In addition, grounding the grounding layer 313 is beneficial to operational safety and saves insulation space.

[0057] The dielectric strength of the material used for the solid insulating layer 312 is usually much greater than the breakdown field strength of air (2.6 kV / mm), and the optional materials include: epoxy resin, silicone resin, silica gel, polyurethane, ceramics, etc.

[0058] The impedance module 330 is connected to the charged body layer 311 in the insulating component 310. If there is leakage in the power electronic converter module 210, the leakage current will be transmitted to the charged body layer 311. The monitoring module 330 monitors the electrical signal between the signal source and the charged body layer 311, and then based on the preset signal processing circuit and algorithm, the insulation resistance value of the insulating component 310 can be determined, and then the insulation condition of the power electronic converter module 210 can be determined according to the insulation resistance value of the insulating component 310.

[0059] Compared with conventional air insulation, the use of grounded shielded solid insulation enables the application of power electronic converter modules in the medium voltage field to still maintain the advantage of high power density, the insulation reliability and mechanism protection are enhanced, and the mechanism installation is simplified.

[0060] In a feasible embodiment of the present invention, the impedance module 330 may include multiple impedance components, for example, any one or more of a resistor R, an inductor L, and a capacitor C. When the impedance module 330 includes multiple impedance components, the multiple impedance components are connected in series, in parallel, or in series and parallel to form an impedance network.

[0061] In another feasible embodiment of the present invention, the impedance module 330 includes at least one LC filter circuit. For example, the filter network may be composed of a single or multiple LC filter circuits connected in parallel and a resistor Rz connected in series.

[0062] Specific reference Figure 5 , Figure 5 A schematic diagram of the structure of an impedance module in an insulation monitoring device for a power system provided by an embodiment of the present invention. Figure 5 In the embodiment, n LC filter circuits (LC1, LC2, ..., LCn) and a single resistor Rz are included, and the n LC filter circuits and the resistor Rz are connected in series to form an impedance network. The impedance module 330 can not only realize the sampling function, but also present high impedance to the switching frequency signal or its higher harmonic signal, filter the detection signal, and improve the monitoring accuracy. In addition, the impedance module 330 can also alleviate the partial discharge amplitude at the characteristic frequency corresponding to the rising / falling edge (t_rise / t_fall) caused by high-speed switching, thereby reducing the high-frequency stress on the solid insulation layer and extending its service life.

[0063] The frequency characteristics of the impedance module 330 can be tuned according to filtering needs to achieve leakage current sampling, and can also control high-frequency leakage current, which not only alleviates the aging problem of insulation material life, but also helps to improve the electromagnetic compatibility (EMC) of the system.

[0064] In a feasible embodiment of the present invention, the circuit node in the above-mentioned power electronic converter module is the midpoint of the bridge arm in the above-mentioned power electronic converter module, and / or the node on the positive and negative DC bus in the above-mentioned power electronic converter module.

[0065] Specific reference Figure 6 , Figure 6 A schematic diagram of the position of a signal source in an insulation monitoring device for an electric power system provided by an embodiment of the present invention. Figure 6 In the figure, the circuit nodes shown in ①, ②, and ③ can all be used as signal sources.

[0066] In another feasible embodiment of the present invention, the above-mentioned circuit node may also be a circuit node in a converter that provides auxiliary power to the power electronic converter module.

[0067] In addition, in a feasible embodiment of the present invention, the voltage waveform of the above-mentioned circuit node contains a DC component.

[0068] In the embodiment of the present invention, the above circuit nodes are used as signal sources, so there is no need for an external signal source and no need to consider the high voltage isolation problem of the monitoring circuit. In addition, since the positions of the signal sources in the power electronic converter module are diverse, a suitable signal source can be selected according to the system operation requirements, which is convenient and flexible.

[0069] Further, based on the insulation monitoring device described in the above embodiment, referring to Figure 7 , Figure 7 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 3 In a feasible embodiment of the present invention, the insulation monitoring device further includes a support portion 710, which is disposed between the power electronic converter module 210 and the charged body layer 311, so that there is a gap between the power electronic converter module 210 and the charged body layer 311. That is, the power electronic converter module 210 is separated from the charged body layer 311 by the support portion 710 (no surface / line electrical contact).

[0070] Among them, the support part 710 is made of insulating material, the impedance module "Z" is arranged outside the support part 710, and is connected in series between the circuit node in the power electronic converter module 210 and the charged body layer 311, and the power electronic converter module 210 is only connected to the charged body layer 311 through the impedance module "Z".

[0071] In a feasible embodiment of the present invention, the impedance module "Z" can also be arranged inside the support portion 710. Figure 8 , Figure 8 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 4 .exist Figure 8 In the embodiment, the insulation monitoring device includes a support portion 810, which is disposed between the power electronic converter module 210 and the charged body layer 311, so that there is a gap between the power electronic converter module 210 and the charged body layer 311. That is, the power electronic converter module 210 is separated from the charged body layer 311 by the support portion 810.

[0072] The support portion 810 is provided with an impedance module “Z” therein, that is, in the embodiment of the present invention, the support portion 810 not only has supporting strength but also serves as an impedance element.

[0073] In another feasible embodiment of the present invention, the support portion 810 may also be at least a part of the impedance module "Z". That is, in the embodiment of the present invention, the impedance module not only serves as an impedance element, but also has supporting strength.

[0074] Further, based on the insulation monitoring device described in the above embodiment, referring to Fig. 9 , Fig. 9 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 5 In a feasible embodiment of the present invention, the insulation monitoring device further includes an insulating layer 910, which is disposed between the power electronic converter module 210 and the charged body layer 311. That is, the power electronic converter module 210 is separated from the charged body layer 311 by the insulating layer 910 (no surface / line electrical contact).

[0075] The insulating layer 910 may be made of insulating paint, insulating glue, fiber products, rubber, plastic and their products; or glass, ceramic products, mica, asbestos and their products, etc.

[0076] In the embodiment of the present invention, the above-mentioned support parts 710, 810 or insulating layer 910 are used to help control the monitoring current path and obtain the sampling signal. The support part provides a monitoring current path, and the required sampling signal can be selectively extracted from one or more support parts, and the structure is flexible and compact.

[0077] Further, based on the insulation monitoring device described in the above embodiment, referring to Fig.10 , Fig.10 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 6In a feasible embodiment of the present invention, when there are multiple power electronic converter modules to be monitored, a centralized impedance "Z0" may be used to monitor the leakage current flowing through all insulators on all power electronic converter modules to be monitored.

[0078] In addition, the impedance module may also include impedance elements distributed on different insulator branches that need to be monitored, such as impedance "Z1" distributed on the insulator branch of the power electronic converter module 201 that needs to be monitored, and used to monitor the insulation condition of the power electronic converter module 201; impedance module "Z2" distributed on the insulator branch of the power electronic converter module 202 that needs to be monitored, and used to monitor the insulation condition of the power electronic converter module 202.

[0079] That is, in the insulation monitoring device provided by the embodiment of the present invention, the position of the impedance module can be flexibly set, so that targeted parameter configuration and connection can be performed according to the position of different insulators.

[0080] In another feasible embodiment of the present invention, the above-mentioned power electronic converter module may include at least one transformer or inductor, and at least one insulating component at least partially covers at least part of the winding of the above-mentioned transformer or inductor; the impedance module corresponding to the above-mentioned insulating component can be connected in series between any electrical node of the above-mentioned winding and the insulating component, or distributed and connected in series between multiple electrical nodes of the above-mentioned winding and the insulating components.

[0081] Reference Fig.11 , Fig.11 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 7 .exist Fig.11 In the embodiment, the insulating component includes a charged body layer 311, a solid insulating layer 312 and a grounding layer 313, and after the insulating component is at least partially covered on at least a part of the winding of the transformer or inductor, the charged body layer 311 is located on a side close to the winding, and the grounding layer 313 is located on a side away from the winding. The impedance module "Z" corresponding to the insulating component is connected in series between any electrical node of the winding and the charged body layer 311 of the insulating component.

[0082] In practical applications, the high voltage stress generated by the winding will be applied entirely to the solid insulating layer 312, and the high voltage winding portion is shielded by the charged body layer 311, which can prevent the air discharge problem inside the circuit. In addition, grounding the grounding layer 313 is also beneficial to operational safety and saves insulation space.

[0083] Among them, if the above-mentioned winding has leakage, the leakage current will be transmitted to the charged body layer 311. By monitoring the electrical signal between the signal source and the charged body layer 311, and then based on the preset signal processing circuit and algorithm, the insulation resistance value of the insulating component can be determined, and then according to the insulation resistance value of the insulating component, the insulation condition of the above-mentioned winding can be determined.

[0084] Reference Fig.12 , Fig.12 A schematic diagram of the structure of an insulation monitoring device for a power system provided by an embodiment of the present invention Figure 8 In another feasible embodiment of the present invention, the impedances "Za" and "Zb" corresponding to the insulating components can be distributed and connected in series at the outlet and inlet ends of the windings.

[0085] Among them, by performing numerical calculations on the sampling signals at both ends of the impedances "Za" and "Zb", the insulation condition of the above winding can be obtained.

[0086] Further, based on the insulation monitoring device described in the above embodiment, the embodiment of the present invention also provides a power system, which includes an insulation monitoring device, which is the insulation monitoring device described in the above embodiment, including an insulation component, a signal source, an impedance module and a monitoring module, wherein the insulation component is at least partially covered on the power electronic converter module, the signal source is electrically coupled to the circuit node in the power electronic converter module, the impedance module is connected in series between the signal source and the insulation component, and the monitoring module is used to monitor the insulation resistance value of the insulation component, so as to determine the insulation state of the power electronic converter module based on the insulation resistance value. Compared with the prior art, the signal source used in the embodiment of the present invention is a circuit node in the power electronic converter module. Since there is no high voltage difference between the signal source and the insulation component, it is not necessary to install an expensive voltage coupling device in the above power system during the insulation monitoring process, and the monitoring cost is low; in addition, the embodiment of the present invention refines the insulation monitoring process to the unit level, and can monitor the insulation state of any power electronic converter module and its internal electrical unit in the power system, which is conducive to improving the reliability of the power system.

[0087] Specifically, the insulation monitoring device can refer to the description in the above embodiments, which will not be repeated here.

[0088] In the several embodiments provided by the present invention, it should be understood that the disclosed insulation monitoring device and the embodiments described above are only exemplary. For example, the division of each module is only a logical function division. There may be other division methods in actual implementation, such as multiple modules can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules, which can be electrical, mechanical or other forms.

[0089] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0090] In addition, each functional module in each embodiment of the present invention may be integrated into one processing unit, or each module may exist physically separately, or two or more modules may be integrated into one unit. The above-mentioned module-composed unit may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0091] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An insulation monitoring device applied to a power system, characterized in that: The power system comprises at least one power electronic converter module, and the insulation monitoring device comprises an insulation component, a signal source, an impedance module and a monitoring module; The insulating assembly at least partially wraps around the power electronic converter module; The signal source is electrically coupled to a circuit node in the power electronic converter module; The impedance module is connected in series between the signal source and the insulating component; The monitoring module is used to monitor the insulation resistance value of the insulating component; the insulating component includes a charged body layer, a solid insulating layer and a grounding layer, and the solid insulating layer is arranged between the charged body layer and the grounding layer; the charged body layer is arranged on the side of the insulating component close to the power electronic converter module; the grounding layer is arranged on the side of the insulating component away from the power electronic converter module and is grounded.

2. The insulation monitoring device according to claim 1, characterized in that: The circuit node is a midpoint of a bridge arm in the power electronic converter module, and / or a node on a positive or negative DC bus in the power electronic converter module.

3. The insulation monitoring device according to claim 1, characterized in that: The circuit node is a circuit node in a converter that provides auxiliary power to the power electronic converter module.

4. The insulation monitoring device according to claim 2 or 3, characterized in that: The voltage waveform of the circuit node contains a DC component.

5. The insulation monitoring device according to claim 1, characterized in that: The insulation monitoring device further includes a support portion, which is disposed between the power electronic converter module and the charged body layer so that a gap exists between the power electronic converter module and the charged body layer.

6. The insulation monitoring device according to claim 5, characterized in that: The support portion is made of insulating material, and the impedance module is arranged inside or outside the support portion.

7. The insulation monitoring device according to claim 5, characterized in that: The support portion is at least a portion of the impedance module.

8. The insulation monitoring device according to claim 1, characterized in that: The insulation monitoring device further comprises an insulating layer, and the insulating layer is arranged between the power electronic converter module and the charged body layer.

9. The insulation monitoring device according to claim 1, characterized in that: The impedance module includes any one or more of a resistor, an inductor, and a capacitor.

10. The insulation monitoring device according to claim 1 or 9, characterized in that: The impedance module includes at least one LC filter circuit.

11. The insulation monitoring device according to claim 1, characterized in that: It comprises a plurality of insulating components, and an impedance module corresponding to each insulating component is connected in series between a corresponding signal source and the insulating component.

12. The insulation monitoring device according to claim 1 or 11, characterized in that: The power electronic converter module includes a transformer or an inductor, and at least one of the insulating components at least partially covers at least a portion of the winding of the transformer or the inductor; the impedance module corresponding to the insulating component can be connected in series between any electrical node of the winding and the insulating component, or distributed in series between multiple electrical nodes of the winding and the insulating component.

13. A power system, characterized in that: The power system comprises an insulation monitoring device, and the insulation monitoring device is the insulation monitoring device according to any one of claims 1 to 12.

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