Stepping type capacitance compensation control cabinet

Abstract

A stepping type capacitance compensation control cabinet comprises a main circuit, one side of the main circuit receives power grid voltage, the other side of the main circuit transmits the power grid voltage to a load, the main circuit is connected with a plurality of branch circuits connected in parallel, each branch circuit corresponds to a fling-cut switch and a capacitor bank, the capacitor banks are different in capacity, and the stepping type capacitance compensation control cabinet further comprises a fling-cut controller. And the switching controller is connected with each switching switch, so that the corresponding capacitor bank is switched into the main circuit in a stepping manner.

Description

Technical Field

[0001] The utility model relates to the field of control cabinets, in particular to a step-type capacitor compensation control cabinet. Background Art

[0002] With the rapid development of the national economy and the improvement of people's living standards, people's demand for electricity is growing, and at the same time, higher requirements are put forward for the reliability and quality of power supply. Due to the continuous increase and instability of load, not only the network structure of the power system has been changed, but also the power distribution of the system has been changed, resulting in unreasonable reactive power distribution of the system. At present, the capacitor compensation in the low-voltage capacitor cabinet has the same group compensation capacity of the capacitors and a large capacity, and the combination of the compensation capacity of the capacitor group is single. For example, there is a compensation cabinet with 10 groups of capacitors, each group of 30Kvar, a total of 300Kvar. Then the compensation capacity can only be 30, 60, 90, etc., and the compensation capacity can only be a multiple of 30Kvar. This will lead to a problem. When the actual value of 25Kvar, 59Kvar, etc. is close to an integer multiple, more than 20 Kvar will not be compensated, resulting in insufficient compensation. This combination switching will cause one more group of capacitors to be overcompensated and one less group of capacitors to be undercompensated.

[0003] Therefore, it is urgent to propose a reasonable reactive power compensation solution to provide the actual required compensation capacity, effectively maintain the voltage level of the system, improve the voltage stability of the system, and thus reduce active network losses. Utility Model Content

[0004] In order to solve the above problems, the technical scheme provides a step-by-step capacitor compensation control cabinet, which realizes the coding switching of the capacitor compensation capacity step value of 5kvar through a reasonable combination of compensation capacity, and achieves the best compensation accuracy of 5kvar. It solves the serious defects of under-compensation capacity or over-compensation capacity in the existing capacitor compensation process, so that the capacitor switching is timely and the reactive power compensation effect is optimal.

[0005] To achieve the above purpose, the technical solution is as follows:

[0006] A step-by-step capacitor compensation control cabinet comprises a main line, one side of which receives grid voltage and the other side transmits it to a load, the main line is connected with a plurality of parallel branches, each branch corresponds to a switching switch and a capacitor group, each capacitor group has a different capacity, and also comprises a switching controller, the switching controller is connected to each switching switch so that the corresponding capacitor group is step-by-step switched into the main line.

[0007] In some embodiments, the branch circuit is provided with ten groups, and the capacities of the capacitor groups are 5kvar, 10kvar, 20kvar respectively, and the other seven groups are 40kvar each.

[0008] In some embodiments, the current detection terminal of the switching controller is connected to the main line through a current transformer.

[0009] In some embodiments, a voltage detection terminal of the switching controller is connected to the main line.

[0010] In some embodiments, the branch circuit is provided with a fuse and a reactor in sequence.

[0011] In some embodiments, the capacitor bank has a corresponding switching indicator light.

[0012] The beneficial effects of this application are:

[0013] The number of paths and the total capacity of the capacitor combination of the utility model can be increased or decreased according to the actual needs of the application occasion, and the capacity of a single capacitor can be appropriately reduced according to the reactive power demand of the on-site load, so as to realize a more perfect capacity combination scheme, that is, some changes can be made in the capacity combination mode to adapt to the needs of specific projects, realize customization, and achieve the best compensation solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following briefly introduces the drawings required for describing the embodiments.

[0015] Figure 1 It is a schematic diagram of the electrical structure of an embodiment of the utility model;

[0016] Figure 2 It is a schematic diagram of the cabinet structure of an embodiment of the utility model. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0018] Please refer to Figure 1-2As shown, a step-by-step capacitor compensation control cabinet includes a main line, one side of the main line receives the grid voltage, and the other side transmits it to the load. The main line is connected with a plurality of parallel branches, each branch corresponds to a switching switch 1 and a capacitor group 2, and each of the capacitor groups 2 has a different capacity. It also includes a switching controller 3, and the switching controller 3 is connected to each of the switching switches 1 so that the corresponding capacitor group 2 is step-by-step switched into the main line.

[0019] In this embodiment, the branch circuit is provided with ten groups, and the capacities of the capacitor groups 2 are 5 kvar, 10 kvar, 20 kvar respectively, and the other seven groups are 40 kvar each.

[0020] In this embodiment, the current detection terminal of the switching controller 3 is connected to the main line through a current transformer 4 .

[0021] In this embodiment, the voltage detection terminal of the switching controller 3 is connected to the main line.

[0022] In this embodiment, the branch circuit is provided with a fuse 5 and a reactor 6 in sequence.

[0023] In this embodiment, the capacitor bank 2 has a corresponding switching indicator light 7 .

[0024] refer to Figure 1 , this embodiment is divided into 10 capacitor group loops, the first one is 5kvar, the second one is 10kvar, the third one is 20kvar, and the fourth to tenth ones are all 40kvar. Starting from the first capacitor group with the smallest compensation capacity, each capacitor is coded according to its compensation capacity, and the coding switching of the switching capacitor compensation capacity step value of 5kvar is realized through the coding control of the switching controller, so as to achieve the best compensation accuracy of 5kvar. From 5kvar, 10kvar, 15kvar... to 315kvar, a variety of compensation capacities can be combined to achieve a compensation effect without dead angles in the power grid;

[0025] The switching controller is the core component of this embodiment. The controller detects the current signal of the system by sampling the current transformer TA, and connects it to the *IS and IS terminals of the controller. The system voltage signal and the switching switch power supply are detected from the lower end of the knife fuse. The voltage signal is connected to the *US and US terminals of the controller, and the switching switch power supply is connected to the V terminal of the controller. Controller numbers 1-10 are 10-way switching control output interfaces, which are respectively connected to 10-way switching switches J1-J10.

[0026] The switching controller K can automatically identify the polarity of the sampled current, without the worry of wiring errors. It calculates and analyzes the collected current and voltage signals to obtain the power factor of the system, and then determines the reactive power actually required. Then it sends a control signal to connect one or more groups of capacitors in the switching switches J1-J10. The capacity of each group increases by a step value of 5kvar until the best capacity combination is reached. That is to say, when the controller detects that the power factor is low and the reactive power is insufficient, the controller sends a signal to close the first group of capacitors 5kvar. If the capacity is still insufficient, the second group of 10kvar is closed. The switching is carried out in sequence and step-by-step until the best compensation capacity actually required by the system is reached.

[0027] The switching controller K can automatically adapt to a variety of coded switching modes, and has a first-come-first-served cycle function. It can calculate the best capacitor switching combination according to the under-compensation capacity or over-compensation capacity of the current power grid, and switch the corresponding capacitors of the capacitor cabinet according to the best capacitor switching combination.

[0028] The number of output channels of the switching controller K can be set, and each channel can be switched step by step, closed or fixed directly.

[0029] The switching controller K has a friendly human-machine interface and is easy to operate. It can display power factor, current, reactive power and voltage.

[0030] refer to Figure 2 This figure mainly illustrates the control principle and wiring relationship of the core components of the step-type capacitor compensation control cabinet of this embodiment, including the capacitor switching controller, sampling transformer, knife-fuse switch, switching switch, reactor, capacitor bank, fuse, lightning arrester and interconnection transmission of various functional components.

[0031] As shown in the figure, in the entire power supply system, the step-type capacitor compensation control cabinet is connected to the power transformer on the grid side, the rear end of the main circuit breaker, and the front end on the load side.

[0032] From top to bottom, the front end of the capacitor compensation control cabinet in the figure is a knife-fuse switch, which plays a role in disconnection, overload and short-circuit protection for the entire control cabinet, preventing overload and short-circuit from burning components during operation; the role of the lightning arrester is to prevent lightning overvoltage; the current transformer mainly detects the current of the line and transmits the current signal to the multi-function meter to detect various electrical parameters in the line; the fuse protects each group of capacitors from overload and short circuit; the switching switch receives the signal of the switching controller to switch the capacitor group; the role of the reactor is mainly to suppress the switching inrush current and harmonics in the line; the capacitor group adopts the star connection method to provide reactive power to the system to improve the power factor;

[0033] This figure mainly illustrates the shell structure of this embodiment, including the front view and side view, the layout of the panel control components and the layout of the components inside the cabinet. The cabinet body adopts an aluminum-zinc plate shell, the door panel is sprayed with anti-corrosion paint, and the cabinet body is floor-mounted.

[0034] In this embodiment, the core component K, the capacitor switching controller, is installed on the front panel of the cabinet, which is convenient for operation and observation of the switching status of the capacitor bank. The switching controller K is equipped with operation buttons and switching indicator lights, fault indicator lights, and a liquid crystal screen to display various electrical parameters such as current, voltage, power factor, etc. The front panel is installed with 10 switching and discharge indicator lights. The lower part of the front panel has ventilation grille heat dissipation holes, which are mainly used for air intake. The rear panel is installed with an axial flow fan for exhaust. The knife fuse switch, fuse, and switching switch are installed on the front of the cabinet. The reactor is installed on the upper rear part of the cabinet for heat dissipation. The capacitor is installed on the lower rear part of the cabinet, and the lightning arrester is installed on the side of the cabinet. See the structural diagram for details. Figure 2 This structural arrangement is convenient for operation and heat dissipation, and is easy to install, operate and maintain.

[0035] Disadvantages of the prior art: The prior art uses capacitors of the same capacity for group switching and each group has a large compensation capacity value, and the compensation capacity is switched in multiples. For example, there is a compensation cabinet with 10 capacitors, each circuit is 30Kvar, and the total is 300Kvar. Then the compensation capacity can only be 30, 60, 90, etc., that is, the compensation capacity can only be a multiple of 30Kvar. This compensation will lead to unstable compensation, and there are defects such as over-compensation if one group of capacitors is put in, and under-compensation if one group of capacitors is put in, etc., which seriously affects the effect of reactive compensation and the consistency of capacitor life.

[0036] Advantages of the present application: The present invention realizes coded switching of switching capacitor compensation capacity with a step value of 5kvar through a combination of capacitors with various compensation capacities, achieves an optimal compensation accuracy of 5kvar, and realizes a compensation effect without dead angles in the power grid.

[0037] The purpose of the utility model is to overcome the deficiencies of the prior art and solve the defects of under-compensation capacity or over-compensation capacity in the existing capacitor compensation process, so as to achieve timely capacitor switching and optimal reactive power compensation effect.

[0038] The present application relates to a step-by-step capacitor compensation control cabinet, which adopts a capacitor grouping method to divide the capacitor group into 5kvar, 10kvar, 20kvar, and 40kvar (wherein 40kvar has 7 circuits), a total of 10 capacitor combinations, and a total capacity of 315kvar. Through these 10 groups of capacitor combinations with different capacities, step-by-step coding switching is performed under the control of a capacitor switching controller, and the step value of the compensation capacity can achieve a compensation accuracy of 5kvar, meeting the minimum compensation capacity requirement of the power grid, thereby achieving timely capacitor switching and optimal reactive power compensation effect.

[0039] The above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application. Other principles and basic structures that are the same or similar to those of the present application are within the protection scope of the present application.

Claims

1. A step-type capacitor compensation control cabinet, characterized in that: The invention comprises a main line, one side of which receives grid voltage and the other side transmits it to a load, the main line being connected to a plurality of parallel branches, each branch corresponding to a switching switch (1) and a capacitor bank (2), each capacitor bank (2) having a different capacity, and a switching controller (3), the switching controller (3) being connected to each switching switch (1) so that the corresponding capacitor bank (2) is switched into the main line in a step-by-step manner.

2. A step-type capacitor compensation control cabinet according to claim 1, characterized in that: The branch circuit is provided with ten groups, the capacities of the capacitor groups (2) are 5kvar, 10kvar, 20kvar respectively, and the other seven groups are all 40kvar.

3. A step-type capacitor compensation control cabinet according to claim 1, characterized in that: The current detection end of the switching controller (3) is connected to the main line via a current transformer (4).

4. A step-type capacitor compensation control cabinet according to claim 3, characterized in that: The voltage detection terminal of the switching controller (3) is connected to the main line.

5. A step-type capacitor compensation control cabinet according to claim 4, characterized in that: The branch circuit is provided with a fuse (5) and a reactor (6) in sequence.

6. A step-type capacitor compensation control cabinet according to claim 5, characterized in that: The capacitor bank (2) is provided with a switching indicator light (7) correspondingly.

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