CN220066891U - High-voltage cascading reactive compensation device and system with bypass function - Google Patents

Abstract

The utility model discloses a high-voltage cascading reactive power compensation device and system with a bypass function. The device comprises a plurality of high-voltage reactive power compensation units, each high-voltage reactive power compensation unit comprises an inversion unit and a bypass contactor, the bypass contactor is connected with the inversion unit in parallel, and the device further comprises a temperature sensor for monitoring the temperature change state of the IGBT unit in the high-voltage reactive power compensation unit. The utility model can effectively judge the state of the bypass contactor by adopting a mode of detecting the direct-current voltage and the temperature of the inversion unit, and accurately confirms whether the system bypass contactor of the cascade H bridge is truly attracted or not.

Description

High-voltage cascading reactive compensation device and system with bypass function

Technical Field

The utility model belongs to the technical field of high-voltage dynamic reactive power compensation, and particularly relates to a high-voltage cascading reactive power compensation device and system with a bypass function.

Background

The high-voltage reactive power compensation device is already a necessary equipment in the industries of new energy, mining, gold smelting and the like, and a high-voltage cascade reactive power compensation device with a bypass function is developed for higher fault tolerance of the equipment. In general, the cascading SVG operates under a high-voltage state and has high insulation requirements on bypass contactors, and the number of bypass contactors used by each set of system is large, so that the cost of the bypass contactors in the system is high. The bypass contactor without feedback contact can effectively save cost.

The bypass contactor without the contact is mostly applied to a low-voltage system at present, is used as a switching device of an inverter power supply and a power grid power supply of a low-voltage off-grid integrated machine, is less in application in a high-voltage system, and is particularly used as a bypass contactor. In a cascade high voltage system, a bypass contactor is connected in parallel with a unit, and if the state of the bypass contactor is not determined, the unit is easily damaged due to unit overshoot. How to detect whether the bypass contactor is in the closed state is an important point of the contactless bypass SVG system.

It should be noted that the statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art.

Disclosure of Invention

In view of the above, the present utility model proposes a high voltage cascaded reactive compensation device and system with bypass function that overcomes or at least partially solves the above-mentioned problems.

The embodiment of the utility model adopts the following technical scheme:

in a first aspect, an embodiment of the present utility model provides a high-voltage cascaded reactive compensation device with a bypass function, where the device includes a plurality of high-voltage reactive compensation units, each of the high-voltage reactive compensation units includes an inverter unit and a bypass contactor, the bypass contactor is connected in parallel with the inverter unit, and the device further includes a temperature sensor for monitoring a temperature change state of an IGBT unit in the high-voltage reactive compensation unit. When the bypass contactor is sucked, the temperature of the IGBT unit detected by the temperature sensor is in a falling state and is always reduced to the internal temperature of a high-voltage cascade system; and the temperature of the IGBT unit detected by the temperature sensor starts to rise from the internal temperature and is in a rising state, and the bypass contactor is determined to be not sucked.

Preferably, the inversion unit comprises an H-bridge unit formed by a plurality of IGBT units and an energy storage capacitor, and the H-bridge unit is connected in parallel with the energy storage capacitor.

Preferably, the device further comprises a voltage detection unit, when the bypass contactor is in an off state, if the IGBT driving module is damaged, the capacitor is charged by current through a freewheel in the IGBT unit, and whether the bypass contactor is in a pull-in state is determined by the voltage detection unit. When the bypass contactor is in an open state, if the inside of the IGBT unit is short-circuited, current flows from the inside of the IGBT unit without passing through the capacitor, whether the contactor is closed or not cannot be judged through the voltage detection unit, and whether the bypass contactor is in a suction state or not is determined through the temperature sensor. When the bypass contactor is in an open state, if the inside of the IGBT unit is open, current flows from the inside of the IGBT unit without passing through the capacitor, whether the contactor is closed or not cannot be judged through the voltage detection unit, and whether the bypass contactor is in a suction state or not is determined through the temperature sensor.

Preferably, the plurality of IGBT cells is four IGBT cells. The high-voltage reactive compensation units are connected in series and then connected into a three-phase power A phase; the high-voltage reactive compensation units are connected in series and then connected into a three-phase B phase; and the high-voltage reactive compensation units are connected in series and then connected into a three-phase C phase.

In a second aspect, an embodiment of the present utility model further provides a high-voltage reactive compensation system, including a high-voltage cascaded reactive compensation device with a bypass function according to the first aspect, and a processor; and a memory arranged to store computer executable instructions that, when executed, cause the processor to perform high voltage reactive compensation on three-phase electricity.

The above at least one technical scheme adopted by the embodiment of the utility model can achieve the following beneficial effects:

the utility model detects the state of the bypass contactor by mainly detecting the DC voltage of the inversion unit and secondarily detecting the temperature of the inversion unit. The state of the bypass contactor can be effectively judged, so that whether the bypass contactor of the cascade H bridge system is truly sucked or not can be accurately confirmed.

The foregoing description of the embodiments of the present utility model is merely an overview of the embodiments of the present utility model, and may be implemented according to the content of the specification, in order to make the above and other objects, features and advantages of the present utility model more obvious, the following specific embodiments of the present utility model will be described.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the utility model. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

FIG. 1 is a schematic diagram of a bypass application of a contactor in a prior art low pressure system;

FIG. 2 is a schematic diagram of a high voltage cascaded reactive compensation unit according to an embodiment of the present utility model;

FIG. 3 is a circuit diagram of a high voltage cascaded reactive compensation unit in an embodiment of the utility model;

FIG. 4 is a schematic structural diagram of a high-voltage cascade reactive compensation device according to an embodiment of the present utility model;

fig. 5 is a schematic structural diagram of a high-voltage cascaded reactive compensation system according to an embodiment of the present utility model.

Detailed Description

In order to make the objects, technical solutions and advantages of the present utility model more apparent, the technical solutions of the present utility model will be clearly and completely described below with reference to specific embodiments of the present utility model and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

The utility model designs a high-voltage cascade reactive compensation device with a bypass function, which aims at the current situation that whether a bypass contactor is in a closed state really cannot be determined in the working process of a high-voltage system.

The following describes in detail the technical solutions provided by the embodiments of the present utility model with reference to the accompanying drawings.

The applicant has made many researches in the technical field of high-voltage dynamic reactive power compensation, in the prior art, a contactor is mainly applied to a low-voltage system as a change-over switch of inversion output and grid output, in the system, the grid output and the inversion output are mutually independent, and a common topological circuit diagram is shown in fig. 1. The bypass contactor and the inverter are independent of each other, and faults of the bypass contactor and the inverter have no great influence on the whole system. However, in the reactive power compensation device of the high voltage cascade connection, the inverter unit is connected in parallel with the contactor, and the state of the bypass contactor directly affects the inverter circuit.

The embodiment of the utility model provides a high-voltage cascade reactive power compensation device with a bypass function, as shown in fig. 2, and provides a high-voltage reactive power compensation unit block diagram in the high-voltage cascade reactive power compensation device with the bypass function, wherein the high-voltage reactive power compensation unit comprises an inversion unit and a bypass contactor, the bypass contactor is connected with the inversion unit in parallel, and the device further comprises a temperature sensor for monitoring the temperature change state of an IGBT unit in the high-voltage reactive power compensation unit. As shown in fig. 3, the inverter unit includes an H-bridge unit formed by a plurality of IGBT units and an energy storage capacitor C2, where the H-bridge unit is connected in parallel with the energy storage capacitor C2, the plurality of IGBT units are an H-bridge circuit formed by four IGBT units Q1, Q2, Q3, Q4, and J is a bypass contactor switch. The position of the temperature sensor can be set according to the requirement, such as in a circuit, and also can be set in an IGBT.

When the inversion unit fails, the bypass contactor J is attracted, and the SVG main control does not send a control instruction to the failed inversion unit. The electric energy flows from L1 to L2 through the contactor direct current without passing through the power switch device IGBT unit. If the bypass contactor is not in actuation, electric energy flows into the L2 through the freewheeling tube of the IGBT unit, and charges the capacitor C2, so that the capacitor C2 is over-voltage, and whether the bypass contactor is in actuation can be judged by detecting voltage. If the internal short circuit fault of the IGBT unit occurs, the bypass contactor can have bypass output no matter whether the bypass contactor is attracted or not, so that whether the bypass contactor is attracted or not can not be judged truly in a mode of collecting direct-current voltage of the inversion unit, and the temperature of the temperature change state of the IGBT unit in the high-voltage reactive compensation unit is required to be collected to assist judgment. Because the IGBT unit can generate heat when current flows, the larger the overcurrent is, the more serious the heat is, when the bypass contactor is normally attracted, the unit temperature detected by the temperature sensor is in a descending state and immediately drops to the internal temperature of the system, and when the bypass contactor is in an unabsorbed state, the IGBT unit can bear the effect of overcurrent in a small current state, and the influence on the system is avoided. The temperature of the IGBT can be rapidly increased under the state of excessive current, so that the temperature detected by the temperature sensor is in an increased state, and the state of the bypass contactor can be assisted to be detected by detecting the working state of the temperature sensor. It can thus be derived that: when the bypass contactor is sucked, the temperature of the IGBT unit detected by the temperature sensor is in a falling state and is always reduced to the internal temperature of a high-voltage cascade system; and the temperature of the IGBT unit detected by the temperature sensor starts to rise from the internal temperature and is in a rising state, and the bypass contactor is determined to be not sucked.

In some examples of the utility model, a plurality of the high-voltage reactive compensation units are connected in series and then connected into a three-phase A phase; the high-voltage reactive compensation units are connected in series and then connected into a three-phase B phase; and the high-voltage reactive compensation units are connected in series and then connected into a three-phase C phase.

As shown in fig. 4, a system topology diagram of the high-voltage cascade reactive compensation device with bypass function is shown. The high-voltage cascade reactive compensation device adopts a chained cascade structure and comprises links formed by connecting a plurality of SVG nodes in series in 3 routes, wherein the links correspond to A, B, C three phases of a power grid respectively. Taking phase a as An example, n+m high-voltage cascaded reactive compensation units are A1 and a2 respectively, an+1 respectively, an+m, each SVG node is provided with a bypass contactor, and KA1 and KA2 respectively. In the prior art, the link is required to be provided with n-level high-voltage cascade reactive compensation units according to voltage levels, but an n+m-level structure is adopted in practical application, wherein the additionally arranged m-level high-voltage cascade reactive compensation units can be used as redundancy backup. The n+m-level high-voltage cascade reactive compensation units work on line simultaneously, and each level of high-voltage cascade reactive compensation unit independently outputs control carrier waves to operate. When an abnormality of a certain high-voltage cascade reactive compensation unit is detected, the fault node can be bypassed through a bypass contactor corresponding to the fault node, so that the fault node is separated from a link.

When any one of the inverter units shown in fig. 3 fails, the bypass contactor J of the inverter unit is engaged, and current flows to the next stage through the bypass contactor J without passing through the inverter unit. When the bypass contactor J is in an off state, if the IGBT unit in the SVG system is not damaged, and only when the driving module of the IGBT is damaged, the capacitor C2 is charged by current through the continuous flow tube in the IGBT unit, so that the voltage of the inversion unit can be increased, and at the moment, whether the bypass contactor is in a suction state can be judged only by detecting the voltage of the inversion unit.

When the bypass contactor is in an open state, if the IGBT unit driving module is damaged, current flows from the inside of the IGBT unit without passing through the capacitor C2, voltage cannot be generated, whether the contactor is closed or not cannot be judged in a voltage detection mode, and the damage in the inside of the IGBT unit causes short circuit, so that the weakening of the overcurrent capacity of the IGBT unit is caused, the secondary damage of a system is possibly caused, and the influence is caused on other units. It is therefore necessary to detect the temperature change of the IGBT cells in the high voltage reactive compensation unit at this time to determine whether the bypass contactor is actually engaged.

When the IGBT is in a seriously damaged open circuit state, if the bypass contactor is not in a suction state, the unit voltage of the phasing cannot be detected, and at the moment, whether the bypass contactor is in the suction state is determined by the temperature sensor.

It can be understood that the high-voltage cascade reactive compensation device with the bypass function can effectively judge the state of the bypass contactor and accurately confirm whether the system bypass contactor of the cascade H bridge is truly attracted or not.

The embodiment of the utility model also provides a high-voltage reactive power compensation system, which comprises a high-voltage cascading reactive power compensation device with a bypass function and a processor; and a memory arranged to store computer executable instructions that when executed cause the processor to perform high voltage reactive compensation on a three phase electrical power, please refer to fig. 5, at a hardware level the electronic device comprises a processor, optionally further comprising an internal bus, a network interface, a memory. The Memory may include a Memory, such as a Random-Access Memory (RAM), and may further include a non-volatile Memory (non-volatile Memory), such as at least 1 disk Memory. Of course, the high voltage reactive compensation system may also include hardware required for other services.

The processor, network interface, and memory may be interconnected by an internal bus, which may be an ISA (Industry Standard Architecture ) bus, a PCI (Peripheral Component Interconnect, peripheral component interconnect standard) bus, or EISA (Extended Industry Standard Architecture ) bus, among others. The buses may be classified as address buses, data buses, control buses, etc. For ease of illustration, only one bi-directional arrow is shown in FIG. 5, but not only one bus or type of bus.

And the memory is used for storing programs. In particular, the program may include program code including computer-operating instructions. The memory may include memory and non-volatile storage and provide instructions and data to the processor.

It should be noted that in the description of the present utility model, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Furthermore, in the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the present utility model, unless specifically stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly attached, detachably attached, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present utility model, unless expressly stated or limited otherwise, a first feature "on" or "under" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature "above", "over" and "on" a second feature may be a first feature directly above or obliquely above the second feature, or simply indicate that the first feature is higher in level than the second feature. The first feature being "under", "under" and "beneath" the second feature may be the first feature being directly under or obliquely under the second feature, or simply indicating that the first feature is level less than the second feature.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and further implementations are included within the scope of the preferred embodiment of the present utility model in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present utility model.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present utility model have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the utility model, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the utility model.

Claims (8)

1. A high voltage cascaded reactive power compensation device with bypass function, the device comprising: the device comprises a plurality of high-voltage reactive power compensation units, wherein each high-voltage reactive power compensation unit comprises an inversion unit and a bypass contactor, the bypass contactor is connected with the inversion unit in parallel, and the device further comprises a temperature sensor for monitoring the temperature change state of an IGBT unit in the high-voltage reactive power compensation unit.

2. The apparatus of claim 1, wherein,

when the bypass contactor is sucked, the temperature of the IGBT unit detected by the temperature sensor is in a falling state and is always reduced to the internal temperature of a high-voltage cascade system;

and the temperature of the IGBT unit detected by the temperature sensor starts to rise from the internal temperature and is in a rising state, and the bypass contactor is determined to be not sucked.

3. The apparatus of claim 1, wherein the inverter unit comprises an H-bridge unit of a plurality of IGBT cells and an energy storage capacitor, the H-bridge unit being connected in parallel with the energy storage capacitor.

4. The apparatus of claim 3, further comprising a voltage detection unit,

when the bypass contactor is in an off state, if the IGBT driving module is damaged, the capacitor is charged by current through a freewheel tube in the IGBT unit, and whether the bypass contactor is in an on state is determined through the voltage detection unit.

5. The apparatus of claim 4, wherein,

when the bypass contactor is in an open state, if the inside of the IGBT unit is short-circuited, current flows from the inside of the IGBT unit without passing through the capacitor, whether the contactor is closed or not cannot be judged through the voltage detection unit, and whether the bypass contactor is in a suction state or not is determined through the temperature sensor.

6. The apparatus of claim 3, wherein the plurality of IGBT cells are four IGBT cells.

7. The apparatus of claim 1, wherein a plurality of said high voltage reactive power compensation units are connected in series and then connected to a three-phase power a phase; the high-voltage reactive compensation units are connected in series and then connected into a three-phase B phase; and the high-voltage reactive compensation units are connected in series and then connected into a three-phase C phase.

8. A high voltage reactive power compensation system comprising a high voltage cascaded reactive power compensation device with bypass function according to any of claims 1-7, a processor; and a memory arranged to store computer executable instructions that, when executed, cause the processor to perform high voltage reactive compensation on three-phase electricity.