Reactive compensation power-saving device for high-power electric appliance

Abstract

The utility model discloses a reactive compensation power-saving device for a high-power electric appliance, which relates to the technical field of power distribution equipment and comprises a motor, a vacuum contactor, a first vacuum circuit breaker, a first isolating switch, a reactor, a capacitor, a first current transformer, a voltage transformer, an overvoltage protector, a first connecting line, a second connecting line and a discharge coil. The first disconnecting switch, the vacuum circuit breaker and the vacuum contactor are sequentially connected in series, the reactor, the first current transformer and the capacitor are sequentially connected in series, and the voltage transformer is connected to the two ends of the capacitor in parallel. One end of the first connecting line is sequentially connected with one end, far away from the first vacuum circuit breaker, of the vacuum contactor and one end, far away from the first current transformer, of the capacitor, the other end of the first connecting line is connected to the overvoltage protector, and the motor is connected with the discharge coil through the second connecting line. According to the invention, the problems of low system power factor, large line loss and poor voltage stability and reliability can be effectively solved.

Description

Technical Field

[0001] The present application relates to the technical field of power distribution equipment, and in particular to a reactive power compensation and power saving device for high-power electrical appliances. Background Art

[0002] At present, my country's 10kV and 6kV distribution networks are huge in scale, with complex load conditions and many high-power inductive loads. Their operation and power quality are more important. Voltage quality is an important indicator of power quality. From the perspective of engineering practicality, voltage quality refers to the deviation between the actual voltage and the ideal voltage, reflecting whether the power provided by the power supply department to users is qualified. Moreover, with the sharp increase in electricity consumption, power quality, especially voltage quality problems, have become increasingly serious, seriously restricting the development of industry and agriculture.

[0003] Capacitor compensation devices are often used to adjust the impedance, voltage, phase, power, etc. of the AC power transmission system. When the capacitor is put into use, a large inrush current will be generated; when the capacitor is removed, a high overvoltage will be generated; the capacitor needs to be fully discharged before it is put into use again. Therefore, when the existing capacitor compensation device is used in a system where the reactive power of electrical equipment changes rapidly or there is an impact load, it is usually equipped with a protection device to achieve flexible control of the active and reactive power flow of the system, thereby achieving the purpose of improving the line transmission capacity, improving the power quality, and improving reliability.

[0004] In the related art, the performance of the capacitor compensation device protection equipment is low, and the capacitor cannot be well protected when a fault occurs in the transmission line. In addition, the service life of the protection equipment is low, which increases the depreciation amount and maintenance cost of the protection equipment, easily reduces the performance of the capacitor, and potentially affects the stability of the transmission line. Therefore, there are technical problems such as large power loss in line operation, poor voltage stability and reliability. Utility Model Content

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a high-power electrical appliance reactive power compensation and power saving device, which can effectively solve the problems of low system power factor, large line loss, poor voltage stability and reliability.

[0006] The present application provides a high-power electrical appliance reactive power compensation and power saving device, comprising: a motor, a vacuum contactor, a first vacuum circuit breaker, a first isolating switch, a reactor, a capacitor, a first current transformer, a voltage transformer, an overvoltage protector, a first connecting line, a second connecting line and a discharge coil;

[0007] The first isolating switch, the vacuum circuit breaker and the vacuum contactor are connected in series in sequence, the reactor, the first current transformer and the capacitor are connected in series in sequence, the voltage transformer is connected in parallel to both ends of the capacitor, one end of the first connecting line is connected in sequence to an end of the vacuum contactor away from the first vacuum circuit breaker and an end of the capacitor away from the first current transformer, the other end of the first connecting line is connected to the overvoltage protector, the motor is connected to the discharge coil through the second connecting line, the end of the first isolating switch away from the vacuum circuit breaker is connected to the second connecting line, and the end of the first isolating switch away from the vacuum circuit breaker is located between the motor and the discharge coil.

[0008] According to the high-power electrical reactive power compensation and power-saving device of the embodiment of the present application, at least the following beneficial effects are achieved: the capacitor assembly is installed next to the motor to compensate for the reactive power consumed by the motor on site, and the capacitor is put into operation or withdrawn from operation at the same time as the motor, so that the reactive power consumed by the motor is compensated on site, thereby reducing the reactive power of the transmission and distribution lines above the installation point, reducing line losses and line voltages, and at the same time, this on-site reactive power compensation can achieve energy-saving effects, and improve the utilization rate of electric energy, increase the stability of the power grid, and extend the service life of the equipment; in addition, the capacitor switching switch uses a capacitor-specific vacuum contactor, a first vacuum circuit breaker, and a first isolating switch, which have a simple structure, less maintenance, and improved mechanical service life, strong breaking capacity, reliable operation, and can effectively avoid the phenomenon of contact and bounce; reduce the apparent power of the power supply, increase the load capacity of the transmission and transformation equipment line, and extend the service life of the electrical control equipment; by setting an overvoltage protector, the damage to the capacitor caused by the overvoltage generated during the operation of the power system and the atmospheric overvoltage can be reduced, thereby ensuring the normal operation of the capacitor. Through this configuration, the present application can effectively solve the problems of low system power factor, large line loss, and poor voltage stability and reliability.

[0009] According to some embodiments of the present application, the high-power electrical appliance reactive power compensation and power saving device also includes a second isolating switch, which is arranged on the second connecting line, and the two ends of the second isolating switch are respectively connected to the motor and the discharge coil.

[0010] According to some embodiments of the present application, the high-power electrical appliance reactive power compensation and power saving device also includes a second vacuum circuit breaker, which is arranged on the second connecting line, and the two ends of the second vacuum circuit breaker are respectively connected to the second isolating switch and the motor.

[0011] According to some embodiments of the present application, the high-power electrical appliance reactive power compensation and power saving device also includes a second current transformer, which is arranged on the second connecting line, and the two ends of the second current transformer are respectively connected to the second vacuum circuit breaker and the motor.

[0012] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0014] Figure 1 A schematic structural diagram of a reactive power compensation and power saving device for high-power electrical appliances provided in an embodiment of the present application. DETAILED DESCRIPTION

[0015] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0016] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0017] In the description of this application, if there is a description of first or second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0018] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0019] At present, my country's 10kV and 6kV distribution networks are huge in scale, with complex load conditions and many high-power inductive loads. Their operation and power quality are more important. Voltage quality is an important indicator of power quality. From the perspective of engineering practicality, voltage quality refers to the deviation between the actual voltage and the ideal voltage, reflecting whether the power provided by the power supply department to users is qualified. Moreover, with the sharp increase in electricity consumption, power quality, especially voltage quality problems, have become increasingly serious, seriously restricting the development of industry and agriculture.

[0020] Capacitor compensation devices are often used to adjust the impedance, voltage, phase, power, etc. of the AC power transmission system. When the capacitor is put into use, a large inrush current will be generated; when the capacitor is removed, a high overvoltage will be generated; the capacitor needs to be fully discharged before it is put into use again. Therefore, when the existing capacitor compensation device is used in a system where the reactive power of electrical equipment changes rapidly or there is an impact load, it is usually equipped with a protection device to achieve flexible control of the active and reactive power flow of the system, thereby achieving the purpose of improving the line transmission capacity, improving the power quality, and improving reliability.

[0021] In the related art, the performance of the capacitor compensation device protection equipment is low, and the capacitor cannot be well protected when a fault occurs in the transmission line. In addition, the service life of the protection equipment is low, which increases the depreciation amount and maintenance cost of the protection equipment, easily reduces the performance of the capacitor, and potentially affects the stability of the transmission line. Therefore, there are technical problems such as large power loss in line operation, poor voltage stability and reliability. In order to solve the above problems, the present application proposes a high-power electrical reactive power compensation and power saving device. The following is a further elaboration of the embodiments of the present application in conjunction with the accompanying drawings.

[0022] Reference Figure 1 The present application provides a reactive power compensation and power saving device for a high-power electrical appliance, comprising: a motor, a vacuum contactor, a first vacuum circuit breaker, a first isolating switch, a reactor, a capacitor, a first current transformer, a voltage transformer, an overvoltage protector, a first connecting line, a second connecting line and a discharge coil; the first isolating switch, the vacuum circuit breaker and the vacuum contactor are connected in series in sequence, the reactor, the first current transformer and the capacitor are connected in series in sequence, the voltage transformer is connected in parallel to both ends of the capacitor, one end of the first connecting line is connected in sequence to an end of the vacuum contactor away from the first vacuum circuit breaker and an end of the capacitor away from the first current transformer, the other end of the first connecting line is connected to the overvoltage protector, the motor is connected to the discharge coil through the second connecting line, the end of the first isolating switch away from the vacuum circuit breaker is connected to the second connecting line, and the end of the first isolating switch away from the vacuum circuit breaker is located between the motor and the discharge coil.

[0023] It should be noted that Figure 1QS2 in the figure represents the first disconnector, QF2 represents the first vacuum circuit breaker, KM represents the vacuum contactor, L represents the reactor, 1TAa and 1TAc represent the first current transformer, C represents the capacitor, TV represents the voltage transformer, FV represents the overvoltage protector, M represents the motor, and D represents the discharge coil.

[0024] It should be noted that capacitors are a type of static reactive power compensation equipment. Its main function is to provide reactive power to the power system and improve the power factor. Using local reactive power compensation can reduce the transmission current of the transmission line, play an important role in reducing line energy loss and voltage drop, improving power quality and increasing equipment utilization.

[0025] It should be noted that the contactor adopts a vacuum contactor, which is mainly composed of a vacuum arc extinguishing chamber and an operating mechanism. The vacuum arc extinguishing chamber has two functions: reliably extinguishing arcs when passing normal working current and frequently cutting off the working current, but it cannot cut off overload current and short-circuit current; the operating mechanism is composed of a holding coil with an iron core and an armature. When the coil is energized, the armature is attracted and the contactor is closed; when the coil loses power, the contactor is disconnected; the holding coil generally has two forms, DC and AC. The vacuum contactor has strong extinguishing ability, good voltage resistance, high operating frequency, long service life, no arc spraying, small size, light weight, and long maintenance cycle.

[0026] It should be noted that the reactor is made of hollow coils without magnetic conductive materials. It can be arranged in three assembly forms: vertical, horizontal and herringbone. When a short circuit occurs in the power system, a large short-circuit current will be generated. If it is not restricted, it is very difficult to maintain the dynamic stability and thermal stability of the electrical equipment. Therefore, in order to meet the requirements of the interrupting capacity of certain circuit breakers, reactors are often connected in series at the outgoing circuit breaker to increase the short-circuit impedance and limit the short-circuit current. Series reactors are mainly used to limit short-circuit currents. They are also connected in series or in parallel with capacitors in filters to limit high-order harmonics in the power grid.

[0027] It should be noted that by setting up a voltage transformer, a device with a winding can reduce the voltage on the capacitor terminals to a specified value within a specified time after the capacitor is disconnected from the power supply. Its working principle is that when the capacitor is disconnected from the power grid, the stored charge is discharged automatically, and the residual voltage of the capacitor is reduced to below the specified value within a specified time. It is one of the main technical measures for capacitor devices to ensure the safety of the equipment itself and maintenance personnel. During normal operation, the voltage transformer works under AC voltage (and is connected between the two terminals of the capacitor group) and presents a very high excitation impedance; after the capacitor is disconnected, it is essentially a decaying DC discharge process. Under the action of DC voltage, the iron core quickly saturates, the iron core inductance of the voltage transformer drops rapidly, and the energy storage of the capacitor is absorbed; when the voltage decays to a lower level, the discharge current also decreases accordingly, and the saturation of the iron core will be reduced at this time, and its inductance begins to rise.

[0028] It should be noted that, by setting the first current transformer, a primary current with a larger value can be converted into a secondary current with a smaller value through a certain transformation ratio, which can be used for protection, measurement, etc. For example, a current transformer with a transformation ratio of 400 / 5 can convert an actual current of 400A into a current of 5A.

[0029] It should be noted that the main function of the first vacuum circuit breaker is to disconnect or switch the current in the transmission line connected to the capacitor to protect the normal operation and safety of the power system. It can also be used to maintain the interconnection and crossing of the load power supply of the power system. The working principle of the first vacuum circuit breaker is: a low-voltage area with low conductivity is formed between the two contacts. When overcurrent or overvoltage occurs, the low-voltage area will be instantly ionized, forming an arc and absorbing energy. At the same time, as the current gradually decreases, the low-voltage area will also re-form and leave a tiny pit on the metal surface next to it. Since there are almost no gas molecules in a vacuum environment, the fluctuation of both the arc temperature and the voltage has only a minimal effect, enabling it to better support the transient current of the high power system.

[0030] It should be noted that by setting the first isolating switch, after opening the switch, a reliable insulation gap is established, and the equipment or line that needs to be repaired is separated from the power supply by an obvious disconnection point to ensure the safety of maintenance personnel and equipment; the first isolating switch and the first vacuum circuit breaker cooperate to perform a switching operation to change the operating mode; it can be used to open and close small currents in the line, such as the charging current of the bushing, busbar, connector, short cable, the capacitive current of the switch equalizing capacitor, the circulating current during the double busbar switching, and the excitation current of the voltage transformer, etc.

[0031] In the present application, the capacitor assembly is installed next to the motor to compensate for the reactive power consumed by the motor on site. The capacitor is put into operation or withdrawn from operation at the same time as the motor, so that the reactive power consumed by the motor is compensated on site, thereby reducing the reactive power of the power transmission and distribution lines above the installation point, reducing line losses and line voltages. At the same time, this on-site reactive compensation can achieve energy-saving effects, improve the utilization rate of electric energy, increase the stability of the power grid, and extend the service life of the equipment; in addition, the capacitor switching switch uses a capacitor-specific vacuum contactor, a first vacuum circuit breaker, and a first isolating switch, which have a simple structure, less maintenance, and improve the mechanical service life. The breaking capacity is strong and the action is reliable, which can effectively avoid the phenomenon of contact throwing and bouncing; reduce the apparent power of the power supply, increase the load capacity of the power transmission and transformation equipment line, and extend the service life of the electrical control equipment; by setting an overvoltage protector, the overvoltage generated during the operation of the power system and the atmospheric overvoltage can be reduced. The damage to the capacitor, ensuring the normal operation of the capacitor. Through this setting, the present application can effectively solve the problems of low system power factor, large line loss, poor voltage stability and reliability.

[0032] Reference Figure 1 It can be understood that the high-power electrical reactive power compensation and power-saving device further includes a second isolating switch, which is arranged on the second connecting line, and the two ends of the second isolating switch are respectively connected to the motor and the discharge coil.

[0033] It should be noted that Figure 1 QS1 in FIG. 1 represents the second isolating switch.

[0034] Reference Figure 1 It can be understood that the high-power electrical reactive power compensation and power-saving device also includes a second vacuum circuit breaker, which is arranged on the second connecting line, and the two ends of the second vacuum circuit breaker are respectively connected to the second isolating switch and the motor.

[0035] It should be noted that Figure 1 QF1 in the figure represents the second vacuum circuit breaker. The main function of the second vacuum circuit breaker is to disconnect or switch the current in the second connecting line to protect the normal operation and safety of the power system. It can also be used to maintain the interconnection and crossing of the load power supply of the power system. The working principle of the second vacuum circuit breaker is: a low-voltage area with low conductivity is formed between the two contacts. When overcurrent or overvoltage occurs, the low-voltage area will be instantly ionized, forming an arc and absorbing energy. At the same time, as the current gradually decreases, the low-voltage area will also re-form and leave a tiny pit on the metal surface next to it. Since there are almost no gas molecules in a vacuum environment, the fluctuation of both the arc temperature and the voltage has only a minimal effect, enabling it to better support the transient current of high power systems.

[0036] It should be noted that by setting up the second isolating switch, after opening the switch, a reliable insulation gap is established, and the equipment or line that needs to be repaired is separated from the power supply with an obvious disconnection point to ensure the safety of maintenance personnel and equipment; the second isolating switch and the second vacuum circuit breaker cooperate to perform a switching operation to change the operating mode; it can be used to open and close small currents in the line, such as the charging current of the bushing, busbar, connector, short cable, the capacitive current of the switch equalizing capacitor, the circulating current during the double busbar switching, and the excitation current of the voltage transformer, etc.

[0037] Reference Figure 1 It can be understood that the high-power electrical reactive power compensation and power-saving device also includes a second current transformer, which is arranged on the second connecting line, and the two ends of the second current transformer are respectively connected to the second vacuum circuit breaker and the motor.

[0038] It should be noted that Figure 1 TA1 and TA2 in the figure represent the second current transformer. By setting the second current transformer, the primary current with a larger value can be converted into a secondary current with a smaller value through a certain transformation ratio, which can be used for protection, measurement, etc. For example, a current transformer with a transformation ratio of 400 / 5 can convert an actual current of 400A into a current of 5A.

[0039] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0040] The above is a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

[0041] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A reactive power compensation and power saving device for high-power electrical appliances, characterized in that: include: A motor, a vacuum contactor, a first vacuum circuit breaker, a first isolating switch, a reactor, a capacitor, a first current transformer, a voltage transformer, an overvoltage protector, a first connecting line, a second connecting line and a discharge coil; The first isolating switch, the vacuum circuit breaker and the vacuum contactor are connected in series in sequence, the reactor, the first current transformer and the capacitor are connected in series in sequence, the voltage transformer is connected in parallel to both ends of the capacitor, one end of the first connecting line is connected in sequence to an end of the vacuum contactor away from the first vacuum circuit breaker and an end of the capacitor away from the first current transformer, the other end of the first connecting line is connected to the overvoltage protector, the motor is connected to the discharge coil through the second connecting line, the end of the first isolating switch away from the vacuum circuit breaker is connected to the second connecting line, and the end of the first isolating switch away from the vacuum circuit breaker is located between the motor and the discharge coil.

2. The high-power electrical appliance reactive power compensation and power saving device according to claim 1 is characterized in that: The high-power electrical appliance reactive power compensation and power-saving device further comprises a second isolating switch, which is arranged on the second connecting line, and the two ends of the second isolating switch are respectively connected to the motor and the discharge coil.

3. The reactive power compensation and power saving device for high-power electrical appliances according to claim 2 is characterized in that: The high-power electrical appliance reactive power compensation and power saving device further comprises a second vacuum circuit breaker, which is arranged on the second connecting line, and the two ends of the second vacuum circuit breaker are respectively connected to the second isolating switch and the motor.

4. The reactive power compensation and power saving device for high-power electrical appliances according to claim 3 is characterized in that: The high-power electrical appliance reactive power compensation and power saving device also includes a second current transformer, which is arranged on the second connecting line, and the two ends of the second current transformer are respectively connected to the second vacuum circuit breaker and the motor.

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