An intelligent capacitor and reactive power compensation system

Abstract

The present application provides an intelligent capacitor and a reactive power compensation system, and relates to the field of reactive power compensation technology. The input end of each capacitor in the intelligent capacitor is connected to the phase line of the power supply bus through a corresponding switch, and each phase line is connected to at least two capacitors. The output end of each capacitor is connected to the neutral line of the power supply bus. The adjustment unit includes a first fixed end, a second fixed end and an adjustment end, the first fixed end is connected to the output end of the capacitor in the preset capacitor unit, and the second fixed end is connected to the neutral line. The adjustment end of the adjustment unit can be connected to the input end of the capacitor in the remaining capacitor units to change the series-parallel relationship of the capacitor connected to the phase line. Since the total capacitance of the capacitor after series and parallel connection is different, changing the series-parallel relationship of the capacitor can change the total capacitance compensated to the phase line. Therefore, the present application can compensate for non-fixed capacitance within a limited capacitor cabinet space, and improve the order gradient of the compensation capacitance, so as to meet customer needs.

Description

Technical Field

[0001] The present application relates to the technical field of reactive power compensation, and in particular to an intelligent capacitor and a reactive power compensation system. Background Art

[0002] Reactive power compensation is an important part of modern power systems. Its main purpose is to improve the power factor of the power supply system, reduce line losses, improve power quality, and improve the stability and efficiency of the power supply system. Smart capacitors are widely used in the field of reactive power compensation because they integrate advanced technologies such as modern measurement and control, power electronics, network communications, and automatic control, and can achieve reactive power compensation more accurately and quickly.

[0003] In the related art, when capacitor cabinet manufacturers configure the capacity of capacitors in smart capacitors, they set it based on 20%~40% of the transformer capacity, usually ignoring the actual load conditions. When the transformer capacity is large and the space in the capacitor cabinet is limited, the capacitance of the capacitors is relatively large and the capacitance does not have a good step gradient. When the actual load is relatively small or the load changes greatly, there is a problem that the capacitance required for compensation is less than the minimum capacitance of the capacitors equipped in the capacitor cabinet, making it impossible for the smart capacitor to perform capacitance compensation according to actual needs, resulting in a low power factor.

[0004] It can be seen that the capacitance that can be compensated by the current smart capacitor is fixed, the compensated capacitance step gradient is not good, and it is impossible to achieve compensation of different capacities in the limited capacitor cabinet space, which makes it difficult to meet the actual needs of customers. Summary of the invention

[0005] The present application provides an intelligent capacitor and a reactive power compensation system to improve the order gradient of the compensated capacitance, thereby realizing compensation of different capacities in a limited capacitor cabinet space.

[0006] In a first aspect, the present application provides a smart capacitor, which is applied to a power system, wherein the power system includes a power supply bus. The smart capacitor includes a plurality of capacitor units, a plurality of switch units, and a regulating unit. Each capacitor unit includes at least one capacitor, each switch unit includes at least one switch, and the capacitors correspond to the switches one by one.

[0007] The input end of each capacitor is connected to the phase line of the power supply bus through a corresponding switch, and each phase line is connected to at least two capacitors; the output end of each capacitor is connected to the neutral line of the power supply bus. The capacitor unit is used to perform reactive power compensation on the power system. The adjustment unit includes a first fixed end, a second fixed end and an adjustment end, the first fixed end is connected to the output end of the capacitor in the preset capacitor unit, and the second fixed end is connected to the neutral line. The adjustment end can be connected to the input end of the capacitor in the remaining capacitor units to change the series-parallel relationship of the capacitor connected to the phase line.

[0008] The capacitors connected to the first fixed end and the adjustment end are connected to the same phase line; the preset capacitor unit is any capacitor unit among the multiple capacitor units, and the remaining capacitor units are any capacitor unit among the multiple capacitor units except the preset capacitor unit.

[0009] Through the above scheme, the setting of the adjustment unit can change the series-parallel relationship of the capacitor connected to the phase line when its adjustment end is connected to the input end of the capacitor in the remaining capacitor units. Since the total capacitance of the two phase-series capacitors is different from the total capacitance of the two phase-parallel capacitors, and the total capacitance of the two phase-series capacitors is less than the total capacitance of the two phase-parallel capacitors, changing the series-parallel relationship of the capacitors connected to the phase line can not only change the total capacitance size compensated to the phase line, but also reduce the total capacitance size compensated to the phase line. Therefore, the intelligent capacitor of the present application can compensate for non-fixed capacitance and improve the order gradient of the compensation capacitance to meet the needs of customers. The present application does not need to adjust the number of capacitors set in the limited capacitor cabinet space, and can only achieve different capacity compensation through the series-parallel combination of the existing capacitors in the capacitor cabinet, and can achieve the maximum compensation capacity unchanged.

[0010] In a possible design, the phase line is the live line, and the input end of each capacitor is connected to the live line. The number of adjustment units is N1, 1≤N1≤the number of capacitor units, and one adjustment unit corresponds to one capacitor unit. Each adjustment unit includes an adjustment member, a first fixed end of the adjustment member is connected to the output end of the capacitor in the corresponding capacitor unit, a second fixed end of the adjustment member is connected to the neutral line, and the adjustment end of the adjustment member can be connected to the input end of the capacitor in the remaining capacitor units.

[0011] Through the above scheme, in a single-phase power supply system, when the regulating end of the regulating member is not connected to the input end of the capacitor in the remaining capacitor units, the two capacitors can maintain the original parallel relationship and be connected in parallel to the power supply system. When the regulating end of the regulating member is connected to the input end of the capacitor in the remaining capacitor units, the series-parallel relationship of multiple capacitors can be changed, and the original parallel relationship of multiple capacitors can be changed to a series relationship, and then connected in parallel to the power supply system. It can be seen that the intelligent capacitor provided by the present application can perform reactive compensation for the capacitance of the live wire in a single-phase power supply system.

[0012] In a possible design, the adjustment element is configured as a single-pole X1-throw switch, and 2≤X1≤the number of capacitor units.

[0013] Through the above solution, for a single-phase power supply system, the type of the adjusting element can be flexibly set according to the number of capacitor units, so that the setting of the adjusting element is more flexible.

[0014] In a possible design, the phase line includes an A phase line, a B phase line, and a C phase line. Each capacitor unit includes three capacitors, the input ends of the three capacitors are respectively connected to the A phase line, the B phase line, and the C phase line, and the output ends of the three capacitors are all connected to the neutral line. The number of adjustment units is N2, 1≤N2≤the number of capacitor units, and one adjustment unit corresponds to one capacitor unit.

[0015] Each adjustment unit includes three adjustment members, and the three adjustment members correspond to the three capacitors in the corresponding capacitor unit. The first fixed end of each adjustment member is connected to the output end of the corresponding capacitor in the corresponding capacitor unit, the second fixed end of each adjustment member is connected to the neutral line, and the adjustment end of each adjustment member can be connected to the input end of the corresponding capacitor in the remaining capacitor units.

[0016] Through the above scheme, in a three-phase power supply system, when the adjustment end of the adjustment member is not connected to the input end of the corresponding capacitor in the remaining capacitor units, the two capacitors can maintain the original parallel relationship and be connected in parallel to the power supply system. When the adjustment end of the adjustment member is connected to the input end of the corresponding capacitor in the remaining capacitor units, the series-parallel relationship of multiple capacitors can be changed, and the original parallel relationship of multiple capacitors can be changed to a series relationship, and then connected in parallel to the power supply system. It can be seen that the intelligent capacitor provided in this application can compensate for the capacitance of each phase line in a three-phase power supply system.

[0017] In a possible design, the adjustment element is configured as a single-pole X2-throw switch, where 2≤X2≤the number of capacitor units.

[0018] Through the above solution, for a three-phase power supply system, the type of the adjusting element can be flexibly set according to the number of capacitor units, so that the setting of the adjusting element is more flexible.

[0019] In a possible design, the regulating element is at least one of a relay, an AC contactor, a thyristor, an insulated gate bipolar transistor and a composite switch. The types of regulating elements are rich and varied, and are not limited to a certain type.

[0020] In a possible design, the capacitance of each capacitor in a single capacitor unit is the same, or the capacitance of each capacitor in a single capacitor unit is different.

[0021] Through the above scheme, when the capacity of each capacitor in a single capacitor unit is the same, the same capacity capacitor can be compensated for each phase line through a single capacitor unit. In addition, after batch production of capacitors of the same specification, they can be applied to smart capacitors, which is convenient for reducing the difficulty of capacitor molding. When the capacity of each capacitor in a single capacitor unit is different, the capacity of each phase line can be compensated for different capacities through a single capacitor unit, which is convenient for compensating capacitors of different capacities according to the actual needs of each phase line.

[0022] In a possible design, the capacitances of the capacitors in all the capacitance units are different, or the capacitances of the capacitors in all the capacitance units are the same.

[0023] Through the above scheme, the capacitance of the capacitors in all capacitor units is different. When multiple capacitors are connected in different series and parallel combinations in a single phase, different capacitances can be compensated to the single phase, which is convenient for capacitor compensation of different capacities according to the actual needs of the single phase. When the capacitance of each capacitor in all capacitor units is the same, the difficulty of forming the capacitor can be reduced.

[0024] In a second aspect, the present application provides a reactive power compensation system, comprising a control unit and the smart capacitor in the first aspect. The control unit is connected to the switch unit of the smart capacitor to control the on and off of the switch unit. The control unit is also connected to the adjustment unit of the smart capacitor to control the on and off of the adjustment end of the adjustment unit and the input end of the capacitor.

[0025] The reactive power compensation system provided in the present application includes an intelligent capacitor. The intelligent capacitor provided in the present application can flexibly change the capacity of the power system to be compensated by adjusting the series-parallel relationship between multiple capacitors. The compensated capacitance step gradient is relatively high, and compensation of different capacities can be achieved within a limited capacitor cabinet space, which can well meet the actual needs of customers. Therefore, the reactive power compensation system including the intelligent capacitor also has the above-mentioned effects that the intelligent capacitor can bring.

[0026] In a possible design, the control unit includes a first circuit board and a second circuit board, the first circuit board is connected to the switch unit, and the second circuit board is connected to the adjustment unit.

[0027] Through the above solution, the first circuit board is connected to the switch unit, and the second circuit board is connected to the adjustment unit, so that the first circuit board can be used to control the switch unit, and the second circuit board can be used to control the adjustment unit. In this way, all functions do not need to be integrated into one circuit board, which is convenient for reducing the difficulty of manufacturing the circuit board in the control unit.

[0028] The beneficial effects of the reactive power compensation system provided in the above-mentioned second aspect and each possible design of the above-mentioned second aspect can be referred to the beneficial effects brought about by the above-mentioned first aspect and each possible implementation method of the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a reactive power compensation system provided in an embodiment of the present application.

[0030] Figure 2 This is a circuit diagram of a smart capacitor provided in an embodiment of the present application.

[0031] Figure 3This is a circuit diagram of the smart capacitor provided in an embodiment of the present application when applied to a single-phase power supply system.

[0032] Figure 4 This is a circuit diagram of the smart capacitor provided in the embodiment of the present application when applied to a three-phase power supply system.

[0033] Description of reference numerals:

[0034] 100. Power system;

[0035] 200. Reactive power compensation system;

[0036] 210, control unit; 211, first circuit board; 212, second circuit board;

[0037] 220, intelligent capacitor; 221, switch unit; 2211, switch; 222, capacitor unit; 2221, capacitor; 223, adjustment unit; 2231, adjustment member; 2232, adjustment end. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification, claims and drawings of this application are intended to cover non-exclusive inclusions.

[0040] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase "embodiments" in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0041] The term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0042] In addition, the terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0043] In the description of the present application, unless otherwise specified, “plurality” means more than two (including two), and similarly, “plurality groups” means more than two (including two).

[0044] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, the "connected" or "connected" of a circuit structure can refer to not only physical connection, but also electrical connection or signal connection. For example, it can be directly connected, that is, physically connected, or indirectly connected through at least one intermediate element, as long as the circuit is connected, or it can be the internal connection of two elements; signal connection can refer to signal connection through a media medium, such as radio waves, in addition to signal connection through a circuit. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0045] Figure 1 is a schematic diagram of a reactive power compensation system 200 provided in an embodiment of the present application. The reactive power compensation system 200 is applied to a power system 100, such as Figure 1 As shown, the reactive power compensation system 200 includes a control unit 210 and a smart capacitor 220 .

[0046] The control unit 210 is connected to the switch unit 221 of the smart capacitor 220 to control the on / off of the switch unit 221. The control unit 210 is also connected to the adjustment unit 223 of the smart capacitor 220 to control the on / off of the adjustment end of the adjustment unit 223 and the input end of the capacitor.

[0047] In the reactive power compensation system 200, the ultimate purpose of the control unit 210 is to control the operation of switching on and off the capacitor in the power system 100. The switching on and off of the capacitor may be collectively referred to as switching.

[0048] The smart capacitor 220 provided in the present application includes a switch unit 221, a capacitor unit 222 and an adjustment unit 223. The capacitor unit 222 includes a capacitor, the switch unit 221 includes a switch, and the adjustment unit 223 includes an adjustment member. Both the switch and the adjustment member can be connected to the capacitor, and the adjustment end of the adjustment member can be connected to the input end of the capacitor.

[0049] When the switch in the switch unit 221 is closed, the capacitor connected to the switch can be put into the power system 100 . Conversely, when the switch in the switch unit 221 is opened, the capacitor connected to the switch can be removed from the power system 100 .

[0050] In addition, when the regulating end of the regulating member in the regulating unit 223 is connected to the input end of the capacitor, multiple capacitors can be connected in series. Conversely, when the regulating end of the regulating member is disconnected from the input end of the capacitor, the original parallel relationship of the multiple capacitors is not changed. In other words, the regulating unit 223 can adjust the series-parallel relationship between the multiple capacitors so that the multiple capacitors can reduce the capacitance invested in the power system 100 when connected in series, or increase the capacitance invested in the power system 100 when connected in parallel.

[0051] It can be seen that both the switch unit 221 and the adjustment unit 223 can directly affect the switching of the capacitor. Therefore, in the present application, on one hand, the control unit 210 can be connected to the switch unit 221 to further control the switching of the capacitor by controlling the on and off of the switch unit 221. On the other hand, the control unit 210 can also be connected to the adjustment unit 223 to further control the switching of the capacitor by controlling the adjustment unit 223.

[0052] The reactive power compensation system 200 provided in the present application includes an intelligent capacitor 220. The intelligent capacitor 220 provided in the present application can flexibly change the capacity of the power system 100 compensated by adjusting the series-parallel relationship between multiple capacitors. The compensated capacitance step gradient is relatively high, and compensation of different capacities can be achieved within a limited capacitor cabinet space, which can well meet the actual needs of customers. Therefore, the reactive power compensation system 200 including the intelligent capacitor 220 also has the above-mentioned effects that the intelligent capacitor 220 can bring.

[0053] Among them, the control unit 210 is connected to the switch unit 221 of the smart capacitor 220, and the switch unit 221 can be controlled by the control unit 210, thereby further controlling whether the capacitor connected to the switch unit 221 is put into the power system 100 or removed from the power system 100. The control unit 210 is connected to the adjustment unit 223 of the smart capacitor 220, and the state of the adjustment unit 223 can be controlled by the control unit 210, so that the adjustment unit 223 can play the function of adjusting the series-parallel relationship between multiple capacitors, thereby flexibly changing the capacity compensated to the power system 100. The setting of the control unit 210 can more intelligently control the switch unit 221 and the adjustment unit 223, which is convenient for improving the intelligence level and performance of the reactive power compensation system 200.

[0054] Exemplarily, the control unit 210 may integrate a monitoring function, a processing function, and a control function. Among them, the monitoring function may be a function of monitoring parameters such as current and voltage in the circuit. The processing function may be a function of determining parameters such as power factor based on parameters such as current and voltage. The control function may be a function of issuing a control instruction to the switch unit 221 and the adjustment unit 223 based on the difference between the determined power factor and a preset power factor threshold.

[0055] In some possible embodiments, Figure 1 As shown, the control unit 210 may include a first circuit board 211 and a second circuit board 212. The first circuit board 211 is connected to the switch unit 221, and the second circuit board 212 is connected to the adjustment unit 223.

[0056] Based on the above description of the control unit 210, in this embodiment, the first circuit board 211, as the control unit 210 for controlling the switch unit 221, may only have a control function, and of course, on the basis of having the control function, at least one of the above-mentioned monitoring function and processing function may be integrated. The second circuit board 212, as the control unit 210 for controlling the regulating unit 223, may also only have a control function, and on the basis of having the control function, at least one of the above-mentioned monitoring function and processing function may be integrated.

[0057] Exemplarily, when the first circuit board 211 has only a control function, the second circuit board 212 may be integrated with a monitoring function, a processing function, and a control function. In this case, the second circuit board 212 may issue a control instruction to the adjustment unit 223 under the coordinated action of its monitoring function, processing function, and control function. The second circuit board 212 may also transmit the determined parameters such as the power factor to the first circuit board 211 after determining the parameters such as the power factor according to the monitored current, voltage, and other parameters, so that the first circuit board 211 having only a control function may issue a control instruction to the switch unit 221 according to the difference between the power factor transmitted by the second circuit board 212 and the preset power factor threshold.

[0058] Similarly, in the case where the second circuit board 212 has only a control function, the first circuit board 211 may be integrated with a monitoring function, a processing function, and a control function. In this case, the first circuit board 211 may issue a control instruction to the switch unit 221 under the coordinated action of its monitoring function, processing function, and control function. The first circuit board 211 may also transmit the determined parameters such as the power factor to the second circuit board 212 after determining the parameters such as the power factor according to the monitored current, voltage, and other parameters, so that the second circuit board 212 having only a control function may issue a control instruction to the adjustment unit 223 according to the difference between the power factor transmitted by the first circuit board 211 and the preset power factor threshold.

[0059] Programs are written on both the first circuit board 211 and the second circuit board 212 to realize their corresponding functions.

[0060] In the embodiment of the present application, the control unit 210 includes a first circuit board 211 and a second circuit board 212, the first circuit board 211 is connected to the switch unit 221, and the second circuit board 212 is connected to the adjustment unit 223, so that the first circuit board 211 can be used to control the switch unit 221, and the second circuit board 212 can be used to control the adjustment unit 223. In this way, it is not necessary to integrate all functions into one circuit board, which is convenient for reducing the difficulty of manufacturing the circuit board in the control unit 210.

[0061] In actual operation, the circuit boards used to control the switch unit 221 and the adjustment unit 223 to perform operations may be more than the above two circuit boards, and this application does not limit this.

[0062] Figure 2This is a circuit diagram of a smart capacitor provided in an embodiment of the present application, and the smart capacitor is applied to a power system. The power system includes power supply systems with different numbers of phases, and the smart capacitor provided in the present application can be applied to a single-phase power supply system, a two-phase power supply system, and a three-phase power supply system with a capacitance compensation requirement. When the smart capacitor is applied to a two-phase power supply system and a three-phase power supply system, the reactive power demand of each phase can be compensated separately.

[0063] The power system includes the power bus. As a very important component in the power system, the power bus is mainly used for power transmission and distribution. In the common three-phase four-wire system, the phase lines of the power bus include phase A, phase B and phase C, and the neutral line of the power bus is phase N. In the single-phase power supply system, the phase line of the power bus is the live line, and the neutral line of the power bus is the neutral line.

[0064] Combination Figure 1 and Figure 2 The smart capacitor 220 includes a plurality of capacitor units 222, a plurality of switch units 221, and an adjustment unit 223, each capacitor unit 222 includes at least one capacitor 2221, each switch unit 221 includes at least one switch 2211, and the capacitors 2221 correspond to the switches 2211 one by one.

[0065] The input end of each capacitor 2221 is connected to the phase line of the power supply bus through the corresponding switch 2211, and each phase line is connected to at least two capacitors 2221. The output end of each capacitor 2221 is connected to the neutral line of the power supply bus.

[0066] The capacitor unit 222 is used to perform reactive power compensation on the power system 100. The switch unit 221 is used to control the switching of the capacitors 2221 in the capacitor unit 222 in the power system 100. The number of the capacitor units 222 is the same as the number of the switch units 221 and corresponds one to one, and the number of the capacitors 2221 in the capacitor unit 222 is the same as the number of the switches 2211 in the switch unit 221 and corresponds one to one, so that the switches 2211 can perform one-to-one control on the capacitors 2221.

[0067] The capacitor 2221 includes an input terminal and an output terminal, the switch 2211 includes a live terminal and a neutral terminal, the input terminal of each capacitor 2221 is connected to the neutral terminal of the corresponding switch 2211, the live terminal of the switch 2211 is connected to the phase line of the power supply bus, and the output terminal of each capacitor 2221 is connected to the neutral line of the power supply bus. In this way, multiple capacitors 2221 can be connected in parallel to the power supply system.

[0068] Since the capacitors 2221 correspond to the switches 2211 one by one, a switch 2211 is provided between each capacitor 2221 and the corresponding phase line. Thus, by controlling the on and off of the switches 2211, the corresponding capacitor 2221 can be controlled to be switched on and off.

[0069] Exemplarily, when a switch 2211 connected to the A-phase line is closed, the capacitor 2221 connected to the switch 2211 can be put into the power system 100 to compensate the capacitance of the A-phase line. On the contrary, when the switch 2211 connected to the A-phase line is disconnected, the capacitor 2221 connected to the switch 2211 is not put into the power system 100, or is cut off from the power system 100, and cannot compensate the capacitance of the A-phase line.

[0070] When the multiple switches 2211 connected to the A-phase line are closed, the capacitors 2221 connected to the multiple switches 2211 can all be put into the power system 100, and the multiple capacitors 2221 are connected in parallel to the power supply system. In this way, the multiple capacitors 2221 can simultaneously perform capacitance compensation on the A-phase line. In this case, the total capacitance compensated to the A-phase line is the sum of the capacitances of the multiple capacitors 2221 put into the A-phase line.

[0071] The above only introduces the influence of switch 2211 on phase A line on capacitor switching as an example. The influence of switch 2211 on other phase lines of the power supply bus on capacitor switching can refer to the introduction of capacitor switching on phase A line. The influence of switch 2211 on other phase lines on capacitor switching will not be expanded here.

[0072] Please continue to refer to Figure 2 The regulating unit 223 may include a first fixed end, a second fixed end and a regulating end 2232, wherein the first fixed end is connected to the output end of the capacitor 2221 in the preset capacitor unit, and the second fixed end is connected to the neutral line. The regulating end 2232 can be connected to the input end of the capacitor 2221 in the remaining capacitor units to change the series-parallel relationship of the capacitor 2221 connected to the phase line.

[0073] The capacitor 2221 connected to the first fixed end and the adjustment end 2232 is connected to the same phase line. The preset capacitor unit is any capacitor unit 222 among the multiple capacitor units 222, and the remaining capacitor units are any capacitor unit 222 among the multiple capacitor units 222 except the preset capacitor unit.

[0074] The adjustment unit 223 includes an adjustment member 2231, the first fixed end of the adjustment unit 223 is the first fixed end of the adjustment member 2231, the second fixed end of the adjustment unit 223 is the second fixed end of the adjustment member 2231, and the adjustment end 2232 of the adjustment unit 223 is the adjustment end 2232 of the adjustment member 2231. The number of the adjustment members 2231 in the adjustment unit 223 can be one or more, which can be specifically determined according to the number of phase lines in the power supply bus.

[0075] The following continues to take the A phase line as an example to introduce the influence of the regulating unit 223 on the capacitor switching. The influence of the regulating unit 2231 on the other phase lines of the power supply bus on the capacitor switching can refer to the introduction of the A phase line capacitor switching, and the influence of the regulating unit 2231 on the other phase lines on the capacitor switching will not be expanded here.

[0076] For example, Figure 2 As shown, assuming that the number of capacitor units 222 is 2, the capacitor 2221 connected to the A-phase line in the first capacitor unit is called a first capacitor, and the capacitor 2221 connected to the A-phase line in the second capacitor unit is called a second capacitor.

[0077] If the first fixed end of a certain adjusting member 2231 in the adjusting unit 223 is connected to the output end of the first capacitor in the first capacitor unit, and the second fixed end of the adjusting member 2231 is connected to the neutral line by default, then when the adjusting end 2232 of the adjusting member 2231 is connected to the input end of the second capacitor in the second capacitor unit, the first capacitor and the second capacitor are equivalent to being connected in series first and then connected in parallel to the power supply system. When the adjusting end 2232 of the adjusting member 2231 is not connected to the input end of the second capacitor, the first capacitor and the second capacitor are equivalent to being directly connected in parallel to the power supply system.

[0078] In this example, the first capacitor unit is equivalent to the preset capacitor unit in the two capacitor units 222, and the second capacitor unit is equivalent to the remaining capacitor units in the two capacitor units 222. This example is only introduced by taking two capacitor units 222 as an example, and does not constitute a limitation on the technical solution of the present application.

[0079] According to this example, when the adjustment end 2232 is not connected to the input end of the capacitor 2221 in the remaining capacitor units, the two capacitors 2221 can maintain the original parallel relationship and be connected in parallel to the power supply system. When the adjustment end 2232 is connected to the input end of the capacitor 2221 in the remaining capacitor units, the series-parallel relationship of the two capacitors 2221 can be changed, and the original parallel relationship of the two capacitors 2221 can be changed to a series relationship, and then connected in parallel to the power supply system.

[0080] In other words, the present scheme assumes that two terminals in the adjusting element 2231 are respectively connected to the output end of the capacitor 2221 in the preset capacitor unit and the neutral line. When the conduction state of the third terminal of the adjusting element 2231 changes, the three terminals of the adjusting element 2231 can realize the connection between the output end of the capacitor 2221 in the preset capacitor unit and the input end of the capacitor 2221 in the remaining capacitor units.

[0081] The smart capacitor 220 provided in the present application includes an adjustment unit 223 and a plurality of capacitor units 222, wherein the first fixed end of the adjustment unit 223 is connected to the output end of the capacitor 2221 in the preset capacitor unit, and the second fixed end of the adjustment unit 223 is connected to the neutral line. When the adjustment end 2232 of the adjustment unit 223 is not connected to the input end of the capacitor 2221 in the remaining capacitor units, the capacitor 2221 in the preset capacitor unit and the capacitor 2221 in the remaining capacitor units have a parallel relationship. When the adjustment end 2232 is connected to the input end of the capacitor 2221 in the remaining capacitor units, the parallel relationship between the capacitor 2221 in the preset capacitor unit and the capacitor 2221 in the remaining capacitor units is changed to a series relationship. It can be seen that the setting of the adjustment unit 223 can change the series-parallel relationship of the capacitor 2221 connected to the phase line when its adjustment end 2232 is connected to the input end of the capacitor 2221 in the remaining capacitor units.

[0082] Since the total capacitance of the two phase-series capacitors 2221 is different from the total capacitance of the two phase-parallel capacitors 2221, and the total capacitance of the two phase-series capacitors 2221 is less than the total capacitance of the two phase-parallel capacitors 2221, changing the series-parallel relationship of the capacitors 2221 connected to the phase line can not only change the total capacitance size compensated to the phase line, but also reduce the total capacitance size compensated to the phase line. Therefore, the smart capacitor 220 of the present application can compensate for non-fixed capacitance and improve the order gradient of the compensation capacitance to meet customer needs.

[0083] Because the intelligent capacitor 220 can change the total capacitance size compensated to the phase line by changing the series-parallel relationship of the capacitors 2221 connected to the phase line, it is not necessary to adjust the number of capacitors 2221 set in the limited capacitor cabinet space, and different capacity compensation can be achieved only by the series-parallel combination of the existing capacitors 2221 in the capacitor cabinet, and the maximum compensation capacity can be unchanged. Among them, when all the capacitors 2221 in the capacitor cabinet are put into use and connected in parallel, the compensated capacitance is the largest, which is the sum of the capacities of all the capacitors 2221.

[0084] In addition, the capacitors 2221 in the capacitor unit 222 correspond one-to-one to the switches 2211 in the switch unit 221, and the input end of each capacitor 2221 is connected to the phase line of the power supply bus through the corresponding switch 2211, so that the switch 2211 can perform one-to-one control over the capacitor 2221, thereby facilitating the accurate control of the switch 2211 over the switching of the capacitor 2221.

[0085] Next, the smart capacitor 220 of the present application will be introduced in detail by taking a single-phase power supply system and a three-phase power supply system as examples.

[0086] Figure 3 2 is a circuit diagram of the smart capacitor 220 provided in the embodiment of the present application when it is applied to a single-phase power supply system. The number of phase lines in the single-phase power supply system is 1, and the phase line can be called a live line. Figure 1 and Figure 3 , the input end of each capacitor 2221 is connected to the live wire.

[0087] When compensating capacitance for a single-phase power supply system, assume that the number of capacitor units 222 is M1, M1≥2, the input end of the capacitor 2221 in each capacitor unit 222 is connected to the live phase line, and the output end of the capacitor 2221 in each capacitor unit 222 is connected to the neutral line.

[0088] Since the number of phase lines in a single-phase power supply system is 1, only one capacitor 2221 may be provided in each capacitor unit 222. The capacitance of the capacitor 2221 may be set according to actual needs. For example, when a larger capacitance needs to be compensated, a large-capacity capacitor 2221 may be configured, and when a smaller capacitance needs to be compensated, a small-capacity capacitor 2221 may be configured.

[0089] When compensating the capacitance for a single-phase power supply system, the number of the adjustment units 223 is N1, 1≤N1≤the number of the capacitance units 222, and one adjustment unit 223 corresponds to one capacitance unit 222.

[0090] Each adjustment unit 223 may include an adjustment member 2231. A first fixed end of the adjustment member 2231 is connected to the output end of the capacitor 2221 in the corresponding capacitor unit 222, a second fixed end of the adjustment member 2231 is connected to the neutral line, and an adjustment end 2232 of the adjustment member 2231 can be connected to the input end of the capacitor 2221 in the remaining capacitor units.

[0091] For example, Figure 3As shown, assuming that M1=2, N1=1, the capacitor 2221 connected to the live wire in the first capacitor unit is C1, the capacitor 2221 connected to the live wire in the second capacitor unit is C2, and the adjustment unit 223 corresponds to C1. Then, the first fixed end of the adjustment member 2231 is connected to the output end of C1, and the second fixed end of the adjustment member 2231 is connected to the neutral line.

[0092] When the regulating end 2232 of the regulating element 2231 is connected to the input end of C2, C1 and C2 are connected in series first and then in parallel to the power supply system. At this time, the total capacity compensated to the live wire C = (C1*C1) / (C1+C2).

[0093] When the regulating end 2232 of the regulating member 2231 is not connected to the input end of C2, C1 and C2 are equivalent to being directly connected in parallel to the power supply system. At this time, the total capacity compensated to the live line is C=C1+C2.

[0094] In this example, the second capacitor unit is equivalent to the remaining capacitor units in the two capacitor units 222 .

[0095] This example only introduces two capacitor units 222 as an example, which does not constitute a limitation on the technical solution of the present application.

[0096] According to this example, in a single-phase power supply system, when the adjustment end 2232 of the adjustment member 2231 is not connected to the input end of the capacitor 2221 in the remaining capacitor units, the two capacitors 2221 can maintain the original parallel relationship and be connected in parallel to the power supply system. When the adjustment end 2232 of the adjustment member 2231 is connected to the input end of the capacitor 2221 in the remaining capacitor units, the series-parallel relationship of multiple capacitors 2221 can be changed, and the original parallel relationship of multiple capacitors 2221 can be changed to a series relationship, and then connected in parallel to the power supply system. It can be seen that the intelligent capacitor 220 provided in this application can perform reactive compensation for the capacitance of the live wire in a single-phase power supply system.

[0097] Based on the description that the number of phase lines in a single-phase power supply system is 1 and only one capacitor 2221 can be provided in each capacitor unit 222, in some embodiments, the adjustment member 2231 can be configured as a single-pole X1 throw switch, 2≤X1≤the number of capacitor units 222.

[0098] In one example, when the number of capacitor units 222 is 2, the adjustment member 2231 can be a single-pole double-throw switch, and the adjustment member 2231 has an adjustment terminal 2232. In this case, as in the previous embodiment of M1=2 and N1=1, when the adjustment terminal 2232 of the adjustment member 2231 is connected to the input terminal of C2, the total capacity C=(C1*C2) / (C1+C2) of the live wire can be compensated. When the adjustment terminal 2232 of the adjustment member 2231 is not connected to the input terminal of C2, the total capacity C=C1+C2 of the live wire can be compensated.

[0099] In one example, when the number of capacitor units 222 is 3, the adjustment member 2231 may be a single-pole double-throw switch or a single-pole triple-throw switch. Assuming that the capacitor 2221 connected to the live wire in the first capacitor unit is capacitor 1 with a capacity of C1, the capacitor 2221 connected to the live wire in the second capacitor unit is capacitor 2 with a capacity of C2, and the capacitor 2221 connected to the live wire in the third capacitor unit is capacitor 3 with a capacity of C3, there are several possible combinations as shown in Table 1 below:

[0100] Table 1 The corresponding relationship between the actual input of capacitors and the live wire compensation capacity

[0101]

[0102] It should be noted that the number of adjusting members 2231 and whether the adjusting members 2231 are single-pole double-throw switches or single-pole triple-throw switches can be set according to actual needs, and this application does not limit this. To achieve the same number of single-phase compensation capacity, the number of adjusting members 2231 can be set relatively small when using a single-pole three-throw switch compared to using a single-pole double-throw switch, thereby achieving the effect of saving the amount of adjusting members 2231.

[0103] In addition, whether the capacitor 2221 is actually put into operation or not can be controlled by the switch 2211 connected to the capacitor 2221. For example, to realize the connection of capacitor 1 and capacitor 3 in parallel, the switch 2211 connecting capacitor 1 and capacitor 3 can be closed. To realize the connection of capacitor 1 and capacitor 2 in series and then in parallel with capacitor 3, the switch 2211 connected to capacitor 1 or capacitor 2 can be closed, and the switch 2211 connected to capacitor 3 can be closed. To realize the connection of capacitor 1, capacitor 2 and capacitor 3 in series, the switch 2211 connected to capacitor 1 or capacitor 2 or capacitor 3 can be closed. Here, only the method of realizing the actual input of capacitor 2221 by controlling the on and off of switch 2211 in combination 3, combination 11 and combination 14 is illustrated. The switching of the actual input method of capacitor 2221 can be controlled by referring to the on and off methods of the above three combinations for the other combinations, which will not be expanded here one by one.

[0104] The above uses the example of 2 and 3 capacitor units 222 to illustrate the effect of the state change of the adjustment member 2231 on the single-phase compensation capacity. In practice, the number of capacitor units 222 can also be any integer greater than 3. The method of realizing different groups of single-phase compensation capacity can refer to the above examples and will not be described one by one here.

[0105] It should also be noted that what is shown in Table 1 is only the combination of the capacitors 2221 included when the number of capacitor units 222 is 3. When the number of capacitor units 222 is greater than 3, there will be more combinations of capacitors 2221. For example, when the number of capacitor units 222 is 5, or in other words, the number of capacitors 2221 corresponding to a single phase is 5, 3 capacitors 2221 can be connected in series, 4 capacitors 2221 can be connected in series, 5 capacitors 2221 can be connected in series, and other series-parallel combinations can be achieved.

[0106] Figure 4 2 is a circuit diagram of a smart capacitor 220 provided in an embodiment of the present application when applied to a three-phase power supply system. The number of phase lines in the three-phase power supply system is 3, and the three phase lines can be called phase A, phase B, and phase C. Figure 4 As shown, the number of capacitor units 222 may be M2, where M2≥2.

[0107] Since the number of phase lines in the three-phase power supply system is 3, the number of capacitors 2221 in each capacitor unit 222 can be set to 3. The capacitance of the capacitor 2221 can be set according to actual needs. For example, when a larger capacitance needs to be compensated, a large-capacity capacitor 2221 can be configured, and when a smaller capacitance needs to be compensated, a small-capacity capacitor 2221 can be configured.

[0108] Input ends of the three capacitors 2221 are connected to the A-phase line, the B-phase line, and the C-phase line, respectively, and output ends of the three capacitors 2221 are all connected to the neutral line.

[0109] When compensating the capacitance for the three-phase power supply system, the number of the adjustment units 223 is N2, 1≤N2≤the number of the capacitor units 222, and one adjustment unit 223 corresponds to one capacitor unit 222. Each adjustment unit 223 corresponds to one capacitor unit 222, but according to the number of adjustment units 223, each capacitor unit 222 may correspond to one adjustment unit 223, or some capacitor units 222 correspond to adjustment units 223, and some capacitor units 222 do not correspond to adjustment units 223.

[0110] The first fixed end of each adjusting member 2231 is connected to the output end of the corresponding capacitor 2221 in the corresponding capacitor unit 222, the second fixed end of each adjusting member 2231 is connected to the neutral line, and the adjusting end 2232 of each adjusting member 2231 can be connected to the input end of the corresponding capacitor 2221 in the remaining capacitor units 222.

[0111] Exemplarily, the capacitor 11 in the first capacitor unit is connected to the A phase line, with a capacity of C11, the capacitor 12 is connected to the B phase line, with a capacity of C12, and the capacitor 13 is connected to the C phase line, with a capacity of C13. The capacitor 21 in the second capacitor unit is connected to the A phase line, with a capacity of C21, the capacitor 22 is connected to the B phase line, with a capacity of C22, and the capacitor 23 is connected to the C phase line, with a capacity of C23. The capacitor 31 in the third capacitor unit is connected to the A phase line, with a capacity of C31, the capacitor 32 is connected to the B phase line, with a capacity of C32, and the capacitor 33 is connected to the C phase line, with a capacity of C33.

[0112] This example is similar to Figure 3 The difference between the embodiments is that the number of phase lines in the power supply system in this example is 3, and Figure 3 In the embodiment, the number of phase lines in the power supply system is 1. Since the smart capacitor 220 provided in the present application is used to compensate the capacitance of each phase, no matter how many phase lines there are in the power supply system, when implementing the capacitance compensation for a single phase, the implementation method can refer to Figure 3 Embodiment, therefore, this example can also realize 14 combinations as shown in Table 1. As long as the capacity of capacitor 2221 in Table 1 is replaced accordingly, the capacitance compensation amount corresponding to each phase in the three-phase power supply system under different combinations can be obtained, which will not be expanded here one by one.

[0113] Based on the description that the number of phase lines in a three-phase power supply system is 3, only three capacitors 2221 can be set in each capacitor unit 222. In some embodiments, the adjustment member 2231 can be configured as a single-pole X2 throw switch, 2≤X2≤the number of capacitor units 222.

[0114] Similar to the setting method of the adjustment member 2231 in the single-phase power supply system, the number of the adjustment members 2231 in the three-phase power supply system, and whether the adjustment member 2231 is a single-pole double-throw switch or a single-pole triple-throw switch, can be set according to actual needs, and this application does not limit this. To achieve the same number of single-phase compensation capacity, the number of adjustment members 2231 can be set relatively small compared to the single-pole double-throw switch, so the effect of saving the amount of adjustment members 2231 can be achieved.

[0115] Regardless of the number of phases of the power supply system, when a single capacitor unit 222 includes multiple capacitors 2221, in some embodiments of the present application, the capacitors 2221 in the single capacitor unit 222 have the same capacity. Alternatively, the capacitors 2221 in the single capacitor unit 222 have different capacities.

[0116] For example, in Figure 2 In the embodiment, the capacities of the three capacitors 2221 in the first capacitor unit may be the same or different from each other. The capacities of the three capacitors 2221 in the second capacitor unit may be the same or different from each other. Similarly, Figure 4 In the embodiment, the capacities of the plurality of capacitors 2221 in each capacitor unit 222 may also be set in the same manner.

[0117] The capacitance of each capacitor 2221 in a single capacitor unit 222 is the same, that is, the specifications of each capacitor 2221 in a single capacitor unit 222 are the same. In this way, when the capacitance of each phase line is compensated by a single capacitor unit 222, the capacitors of the same capacitance can be compensated. Moreover, after the capacitors 2221 of the same specification are mass-produced, they can be applied to the smart capacitor 220, which is convenient for reducing the difficulty of forming the capacitor 2221.

[0118] The capacity of each capacitor 2221 in a single capacitor unit 222 is different, that is, the specifications of each capacitor 2221 in a single capacitor unit 222 are different. In this way, when the capacitance compensation of each phase line is performed through a single capacitor unit 222, capacitors of different capacities can be compensated, which is convenient for performing capacitance compensation of different capacities according to the actual needs of each phase line.

[0119] Regardless of the number of phases of the power supply system, when a single capacitor unit 222 includes multiple capacitors 2221, in other embodiments of the present application, the capacity of each capacitor 2221 in all capacitor units 222 is the same. Alternatively, the capacity of the capacitors 2221 in all capacitor units 222 is different.

[0120] For example, in Figure 2 In the embodiment, there are three capacitors 2221 in the first capacitor unit and three capacitors 2221 in the second capacitor unit. The capacities of the six capacitors 2221 may be the same, or they may be different. Of course, the capacities of some capacitors 2221 may be the same, and the capacities of some capacitors 2221 may be different. Similarly, Figure 4 In the embodiment, the capacities of the multiple capacitors 2221 in all the capacitor units 222 may also be set in the same manner.

[0121] The capacities of the capacitors 2221 in all capacitor units 222 are different. When multiple capacitors 2221 are connected in different series-parallel combinations in a single phase, different capacitances can be compensated to the single phase, which is convenient for performing capacitance compensation of different capacities according to the actual needs of the single phase. The capacities of the capacitors 2221 in all capacitor units 222 are the same, that is, the specifications of the capacitors 2221 in all capacitor units 222 are the same, so that the difficulty of forming the capacitors 2221 can be reduced.

[0122] In some embodiments, the regulating element 2231 is at least one of a relay, an AC contactor, a thyristor, an insulated gate bipolar transistor, and a compound switch.

[0123] Relays, AC contactors, thyristors, insulated gate bipolar transistors and compound switches can all realize the function of a single-pole multi-throw switch. Therefore, in this application, regardless of whether the power supply system is a single-phase power supply system or a three-phase power supply system, or a power supply system with other phases, the adjustment component 2231 can be set as a relay, an AC contactor, a thyristor, an insulated gate bipolar transistor or a compound switch.

[0124] In the present application, there are multiple adjusting members 2231, and the types of the multiple adjusting members 2231 can be the same or different. As long as the function of a single-pole multi-throw switch can be realized, the adjusting end 2232 of the adjusting member 2231 can be connected to the input end of the corresponding capacitor 2221 in the remaining capacitor units 222. The embodiments of the present application do not limit this.

[0125] In the present application, the regulating element 2231 can be set to at least one of a relay, an AC contactor, a thyristor, an insulated gate bipolar transistor and a compound switch. The types of the regulating element 2231 are rich and varied. When adjusting the series-parallel relationship between multiple capacitors 2221, no special requirements are made on the type of the regulating element 2231.

Claims

1. A smart capacitor, applied to a power system, wherein the power system includes a power supply bus, characterized in that: The smart capacitor comprises: a plurality of capacitor units, a plurality of switch units, and an adjustment unit, each of the capacitor units comprises at least one capacitor, each of the switch units comprises at least one switch, and the capacitors correspond to the switches one by one; The input end of each capacitor is connected to the phase line of the power supply bus through the corresponding switch, and each phase line is connected to at least two capacitors; the output end of each capacitor is connected to the neutral line of the power supply bus; the capacitor unit is used to perform reactive power compensation on the power system; The regulating unit includes a regulating member, the regulating member includes a first fixed end, a second fixed end and an regulating end, the first fixed end is connected to the output end of the capacitor in the preset capacitor unit, the second fixed end is connected to the neutral line; the regulating end can be connected to the input end of the capacitor in the remaining capacitor units to change the series-parallel relationship of the capacitor connected to the phase line; Among them, the capacitors connected to the first fixed end and the adjustment end are connected to the same phase line; the preset capacitor unit is any capacitor unit among the multiple capacitor units, and the remaining capacitor units are any capacitor unit among the multiple capacitor units except the preset capacitor unit.

2. The smart capacitor according to claim 1, characterized in that: The phase line is a live line, and the input end of each capacitor is connected to the live line; The number of the adjustment units is N1, 1≤N1≤the number of the capacitor units, and one adjustment unit corresponds to one capacitor unit; Each of the adjusting units includes one adjusting member.

3. The smart capacitor according to claim 2, characterized in that: The adjustment element is configured as a single-pole X1-throw switch, and 2≤X1≤the number of the capacitor units.

4. The smart capacitor according to claim 1, characterized in that: The phase lines include phase A, phase B and phase C; Each of the capacitor units includes three capacitors, the input ends of the three capacitors are respectively connected to the A-phase line, the B-phase line and the C-phase line, and the output ends of the three capacitors are all connected to the neutral line; The number of the adjustment units is N2, 1≤N2≤the number of the capacitor units, and one adjustment unit corresponds to one capacitor unit; Each of the adjustment units includes three adjustment members, and the three adjustment members correspond one-to-one to the three capacitors in the corresponding capacitor unit.

5. The smart capacitor according to claim 4, characterized in that: The adjustment element is configured as a single-pole X2-throw switch, and 2≤X2≤the number of the capacitor units.

6. The smart capacitor according to claim 2 or 4, characterized in that: The regulating element is at least one of a relay, an AC contactor, a thyristor, an insulated gate bipolar transistor and a composite switch.

7. The smart capacitor according to any one of claims 1 to 5, characterized in that: The capacitance of each capacitor in a single capacitor unit is the same, or the capacitance of each capacitor in a single capacitor unit is different.

8. The smart capacitor according to any one of claims 1 to 5, characterized in that: The capacitances of the capacitors in all the capacitance units are different, or the capacitances of the capacitors in all the capacitance units are the same.

9. A reactive power compensation system, characterized in that: Comprising a control unit and the smart capacitor according to any one of claims 1 to 8; The control unit is connected to the switch unit of the smart capacitor to control the on and off of the switch unit; The control unit is also connected to the regulating unit of the intelligent capacitor to control the connection and disconnection between the regulating end of the regulating unit and the input end of the capacitor.

10. The reactive power compensation system according to claim 9, characterized in that: The control unit includes a first circuit board and a second circuit board, the first circuit board is connected to the switch unit, and the second circuit board is connected to the adjustment unit.

Images