CN111049141A - Intelligent power saving device and method for tail end of power distribution network - Google Patents

Intelligent power saving device and method for tail end of power distribution network Download PDF

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Publication number
CN111049141A
CN111049141A CN202010000766.5A CN202010000766A CN111049141A CN 111049141 A CN111049141 A CN 111049141A CN 202010000766 A CN202010000766 A CN 202010000766A CN 111049141 A CN111049141 A CN 111049141A
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China
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phase
capacitor
switch circuit
electronic switch
compensation capacitor
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CN202010000766.5A
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于庆广
胡剑
张金波
孙天予
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Beijing Chaoneng Technology Co Ltd
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Beijing Chaoneng Technology Co Ltd
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Priority to CN202010000766.5A priority Critical patent/CN111049141A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention relates to an intelligent power-saving device and method at the tail end of a power distribution network, which comprises an air switch, an intelligent measurement and control unit, a first electronic switch circuit, a second electronic switch circuit and a capacitor, wherein the air switch is connected with the intelligent measurement and control unit; one end of the air switch is connected with a low-voltage power grid, the other end of the air switch is connected with the intelligent measurement and control unit through the first electronic switch circuit and the second electronic switch circuit, and the first electronic switch circuit and the second electronic switch circuit are both connected with the capacitor; the intelligent measurement and control unit is powered by a low-voltage power grid, receives a first electronic switch circuit, a second electronic switch circuit and signals transmitted to the capacitor, receives electric quantity parameters transmitted to a guide rail ammeter connected with the low-voltage power grid, obtains reactive demand and control and protection parameters, outputs control and protection signals to the first electronic switch circuit and the second electronic switch circuit to execute signal instructions, and completes switching of the capacitor. The invention has the characteristics of small volume, low power consumption, good heat dissipation, simple and convenient maintenance and the like.

Description

Intelligent power saving device and method for tail end of power distribution network
Technical Field
The invention relates to an electrical control device and a method, in particular to a tail end intelligent power saving device and a method for a low-voltage distribution network.
Background
Because the terminal power saving equipment of the 380V AC low-voltage distribution network has the advantages of low investment, obvious power saving effect, large market demand and wide related range, the popularization and the application of the power saving technology and the equipment in the field are paid attention and paid attention all the time. But the current power-saving products are not mature. The main types are:
the first kind is formed by assembling main devices such as a common reactive compensation controller, a fuse wire (or an air switch), a special alternating current contactor, a thermal relay, a power capacitor and the like in a cabinet and a cabinet surface, the products are old products used for many years and can meet the requirement of a basic reactive compensation function, but the switching response speed of the products is low, switching oscillation is easy to generate, overvoltage and large inrush current are generated in the switching process, contacts are ignited and sintered, the service lives of the switch and the capacitor are short, the switch and the capacitor do not have a networking communication function and are large in size, the wiring in the cabinet is complex, the power consumption is large, and the production and the transportation are extremely inconvenient.
The second type is formed by assembling main devices such as a conventional reactive compensation controller, a fuse (or an air switch), an intelligent composite switch, a thermal relay, a power capacitor and the like in a cabinet and a cabinet surface; compared with the first class, the product is advanced on a switching switch, zero-crossing contactless switching can be realized, no overvoltage, small inrush current or even no inrush current exists in the switching process, the service lives of the capacitor and the switch are prolonged, and the use requirements of special occasions such as inflammable and explosive occasions (such as coal mines, gas stations and the like are not allowed to generate sparks) can be met. But is expensive and unacceptable to the average user, while otherwise similar to the first category.
The third type is that devices such as a controller and a fling-cut switch are fixed in upper grooves of two capacitors, the two capacitors are fixed together through a clamp, the top of the two capacitors is covered by an upper cover and fixed with a lower end capacitor, namely, the integrated intelligent low-voltage power capacitor is an integrated intelligent low-voltage power capacitor. On the other hand, the switching capacitor switch of the product adopts a magnetic latching relay with a mechanical contact, and the zero crossing point switching of the switching capacitor switch is mainly ensured by the consistency of mechanical action, but in practice, due to the limitation of the whole magnetic latching relay manufacturing process level, the consistency of relay action (attraction and release) reaching a few milliseconds is often difficult to ensure, so that the zero crossing point detection is often failed when the zero crossing point is delayed to the zero crossing point in the next half cycle, and the zero crossing point switching capacitor is often completed by software and the consistency of mechanical action, and because the actual switching is often not zero, overvoltage operation and impact current are generated, so that the relay is often burnt, and the capacitor capacity is attenuated or bubbly. Therefore, the product has extremely high failure rate and short service life in the actual use process, is not suitable for special occasions, and once the product fails, the whole machine must be disassembled and replaced, thereby increasing the maintenance cost.
The construction of the current ubiquitous power internet of things emphasizes the realization of the combination of various information sensing devices and communication information resources. Timely uploading of operating parameters of electrical equipment at the end of an industrial enterprise and effective analysis of the operating parameters are a development trend, which is helpful for realizing more intelligent industrial-level control decisions. Therefore, it is necessary for the terminal intelligent power saving device to perform function enhancement and upload the parameters thereof to the enterprise server for decision analysis.
Disclosure of Invention
Aiming at the technical problems of large power consumption, high price, inconvenient replacement and the like of the existing reactive power compensation equipment at the tail end of the low-voltage distribution network, the invention aims to provide the intelligent power saving device and the intelligent power saving method at the tail end of the distribution network, and the intelligent power saving device and the intelligent power saving method have the characteristics of small volume, small power consumption, reasonable structure, low price, good heat dissipation, simple and convenient production, assembly and maintenance and the like.
In order to achieve the purpose, the invention adopts the following technical scheme: an intelligent power saving device at the tail end of a power distribution network comprises an air switch, an intelligent measurement and control unit, a first electronic switch circuit, a second electronic switch circuit and a capacitor; one end of the air switch is connected with a low-voltage power grid, the other end of the air switch is connected with the intelligent measurement and control unit through the first electronic switch circuit and the second electronic switch circuit, and the first electronic switch circuit and the second electronic switch circuit are both connected with the capacitor; the intelligent measurement and control unit is supplied with power by the low-voltage power grid, receives the first electronic switch circuit, the second electronic switch circuit and the signals transmitted to by the capacitor, receives the electric quantity parameters transmitted to by the guide rail electricity meter connected with the low-voltage power grid, obtains the reactive demand and the control and protection parameters, outputs the control and protection signals to the first electronic switch circuit and the second electronic switch circuit to execute signal instructions, and completes the switching of the capacitor.
Furthermore, the intelligent measurement and control unit is provided with a 485 bus interface for communication control.
Further, the guide rail ammeter is connected with the low-voltage power grid through a current transformer CT.
Furthermore, the capacitor adopts a co-compensation capacitor with a built-in temperature sensor and each phase of series inductance, and a sub-compensation capacitor with a built-in temperature sensor and each phase of series inductance.
Further, the common compensation capacitor is a three-phase common compensation capacitor, and the sub-compensation capacitors are three-phase sub-compensation capacitors.
Further, the three-phase common compensation capacitor is connected with the first electronic switch circuit; the three-phase compensation capacitor is connected with the second electronic switch circuit.
Furthermore, a touch screen, a communication interface and a control interface are arranged on the intelligent measurement and control unit; and displaying the working state and the fault indication mark on the touch screen.
Furthermore, the first electronic switch circuit and the second electronic switch circuit respectively comprise a zero-crossing trigger unit, a double thyristor, a high-power magnetic latching relay and a zero-crossing measurement and control overvoltage protection module; and after being connected in anti-parallel with the double crystal thyristors, the zero-crossing trigger unit is connected in parallel with the high-power magnetic latching relay and the zero-crossing measurement and control overvoltage protection module.
A control method based on the intelligent power saving device comprises the following stepsThe method comprises the following steps: 1) setting parameters: the capacity of the common compensation capacitor is Q1The capacity of the sub-compensation capacitor A, B, C is Q2-A、Q2-B、Q2-CThe rated phase voltage of the power grid is UNMaximum operating temperature T of the apparatusHMinimum operating temperature T of the apparatusLSwitching time interval t of equipment capacitor and highest phase current IH(ii) a 2) Acquiring real-time parameters: the intelligent measurement and control unit reads the phase voltages of all phases of the power grid A, B, C through the ammeter and respectively obtains the phase voltages of the phases as UA、UB、UCPhase currents are respectively IA、IB、ICThe power factors are respectively pfA、pfB、pfCReactive power is respectively QA、QB、QCAcquiring the temperature T of the equipment; 3) pre-judging: if U isAOr UBOr UCGreater than 1.1UNOr U isAOr UBOr UCLess than 0.9UNOr T is greater than THOr T is less than TLOr IAOr IBOr ICIs greater than IHIf the judgment is not passed, the equipment cuts off all the capacitors and returns to the step 2); otherwise, the pre-judgment is passed, and the step 4) is carried out; 4) judging switching conditions; 5) when the preset switching interval time t is reached, switching the capacitor judged to be switched in the step 4) at the current zero crossing point, and executing the step 7); 6) when the preset switching interval time t is reached, cutting off the cut-off capacitor judged in the step 4) at the current zero crossing point, and executing the step 7); 7) the intelligent measurement and control unit uploads the action information of the capacitor and the currently acquired electrical parameters in the step 2) to an enterprise server through a wired or wireless network, and the step 2) is returned.
Further, the switching condition is judged as follows: 4.1) if min { QA,QB,QCIs greater than Q1If the common compensation capacitor is not put into the capacitor, judging that the common compensation capacitor is put into the capacitor, and executing the step 5), otherwise, executing the next step; 4.2) if QAGreater than Q2-AIf the A phase of the sub-compensation capacitor is not input, judging that the A phase of the sub-compensation capacitor is input, and executing the step 5), otherwise, executing the next step; 4.3) if QBGreater than Q2-BAnd if the B phase of the sub-compensation capacitor is not put into the device, judging that the B phase of the sub-compensation capacitor is put into the device, and executing the step 5), otherwise, executing the next step; 4.4) if QCGreater than Q2-CAnd if the sub-compensation capacitor C phase is not put into the device, judging that the sub-compensation capacitor C phase is put into the device, and executing the step 5), otherwise, executing the next step; 4.5) if QAIf the phase A of the partial compensation capacitor is less than 0 and the phase A of the partial compensation capacitor is already put into the device, judging that the phase A of the partial compensation capacitor is cut off, and executing the step 6), otherwise, executing the next step; 4.6) if QBIf the phase number of the sub-compensation capacitor B is less than 0 and the phase number of the sub-compensation capacitor B is already input, judging to cut the phase number of the sub-compensation capacitor B, and executing the step 6), otherwise, executing the next step; 4.7) if QCIf the number of the phases is less than 0 and the sub-compensation capacitor C phase is already put into the device, judging to cut the sub-compensation capacitor C phase, and executing the step 6), otherwise, executing the next step; 4.8) if QA、QB、QCAre all smaller than 0, and the complementary capacitors are already put into use, the complementary capacitors are judged to be cut off, step 6) is executed, and otherwise, the step 2) is returned.
Due to the adoption of the technical scheme, the invention has the following advantages: 1. the invention has the protection functions of environment temperature over-value, overvoltage, overcurrent, no-load, power failure, phase loss and misoperation; meanwhile, the LED lamp has the characteristics of smaller volume and power consumption, more reasonable structure, lower price, better heat dissipation, and simplicity and convenience in production, assembly and maintenance. 2. The invention can replace the functions of a controller, a display instrument, an indicator light, a change-over switch, a fuse (or an air switch), a compound switch (or an alternating current contactor), a heat relay and other radiating devices in a low-voltage reactive power compensation system after being assembled, has the functions of protecting environment temperature from over-value, overvoltage, overcurrent, no-load, power failure, phase failure and misoperation, and has the superior performances of no overvoltage, no inrush current generation and rapid compensation in the switching process. The invention can also upload the relevant operation parameters of the intelligent power saving device and the parameters of the tail end power grid to the server of the enterprise in time for decision analysis of the enterprise.
Drawings
FIG. 1 is a schematic view of the overall structure of the apparatus of the present invention;
FIG. 2 is a schematic flow diagram of the process of the present invention.
Detailed Description
In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance, and therefore should not be construed as limiting the present invention. The invention is described in detail below with reference to the figures and examples.
As shown in fig. 1, the invention provides an intelligent power saving device at the end of a power distribution network, which comprises an air switch, an intelligent measurement and control unit, a first electronic switch circuit, a second electronic switch circuit and a capacitor.
One end of the air switch is connected with a low-voltage power grid, the other end of the air switch is connected with the intelligent measurement and control unit through the first electronic switch circuit and the second electronic switch circuit, and the intelligent power-saving device is connected in parallel to the power grid or cut off from the low-voltage power grid through the opening and closing of the air switch and used for carrying out overcurrent protection on the intelligent power-saving device. The first electronic switching circuit and the second electronic switching circuit are both connected with the capacitor; the intelligent measurement and control unit is powered by a low-voltage power grid, receives signals transmitted by the first electronic switch circuit, the second electronic switch circuit and the capacitor, receives electric quantity parameters transmitted by a guide rail ammeter connected with the low-voltage power grid, further obtains reactive demand and other control and protection parameters, outputs control and protection signals to the first electronic switch circuit and the second electronic switch circuit to execute signal instructions, and finishes switching of the capacitor. Wherein, the intelligent measurement and control unit is also provided with a 485 bus interface for communication control and is used for being connected with an external controller.
In the above embodiment, the guide rail electricity meter is connected to the low-voltage power grid through the current transformer CT, so as to obtain a current signal of the low-voltage power grid.
In the above embodiments, the capacitor may be a co-compensation capacitor with a built-in temperature sensor and a built-in series inductance per phase, and a sub-compensation capacitor with a built-in temperature sensor and a built-in series inductance per phase. The capacitor transmits the detected temperature signal to the intelligent measurement and control unit.
The three-phase compensation capacitor is a three-phase compensation capacitor, and the three-phase compensation capacitor is a three-phase compensation capacitor. The three-phase common compensation capacitor is connected with the first electronic switch circuit to realize the switching of the capacitor; the three-phase compensation capacitor is connected with the second electronic switch circuit to realize the switching of the capacitor.
In the above embodiments, the intelligent measurement and control unit is provided with a touch screen, a communication interface and a control interface. And displaying the working state and the fault indication mark on the touch screen.
In the above embodiments, the first electronic switch circuit and the second electronic switch circuit both include a zero-crossing trigger unit, a thyristor, a high-power magnetic latching relay, and a zero-crossing measurement and control overvoltage protection module; after being connected in anti-parallel with the double crystal thyristors, the zero-crossing trigger unit is connected in parallel with the high-power magnetic latching relay and the zero-crossing measurement and control overvoltage protection module. When the circuit is used, the first electronic switch circuit and the second electronic switch circuit switch capacitors have no inrush current impact and no overvoltage, can frequently act, and have long service life.
In the above embodiments, the intelligent power saving device of the present invention has the protection functions of environment temperature over-value, overvoltage, overcurrent, no-load, power failure, phase failure and misoperation, can be used independently by a single device, and can also be used by a system formed by networking a plurality of devices, and the capacitor switching process has no overvoltage and no inrush current; meanwhile, the LED lamp has the characteristics of smaller volume and power consumption, more reasonable structure, lower price, better heat dissipation, and simplicity and convenience in production, assembly and maintenance.
In the above embodiments, the intelligent power saving device can replace the functions of the low-voltage reactive compensation system, such as a controller, a display instrument, an indicator light, a transfer switch, a fuse (or an air switch), a compound switch (or an ac contactor), a thermal relay and other dissipation devices, which are assembled and completed, has the functions of protecting environment temperature from over-voltage, over-current, no-load, power failure, phase failure and misoperation, and has the superior performances of no overvoltage, no inrush current and rapid compensation in the switching process.
In the above embodiments, the intelligent measurement and control unit may adopt a programmable controller.
In conclusion, when the intelligent power saving device is used, the intelligent measurement and control unit adopts the ultra-strong anti-interference programmable controller, the whole system carries out self-checking, and the technologies of a capacitor for detecting the ambient temperature, reactive power flow prediction, time-delay multipoint sampling, data communication and the like are added, so that the intelligent measurement and control unit is ensured to be free of dead halt in the working process, and the reliability is extremely high; when the temperature exceeds the value, the capacitor is cut off rapidly and is locked for control, and switching oscillation caused by inaccurate instantaneous single-point sampling can be effectively avoided by multi-point sampling; the dynamic response time is short, so that a capacitor bank input instruction is rapidly sent out under the condition of heavy load, and the switching waiting time is reduced; the communication interface can be convenient for organically combine a plurality of devices to form a work queue, and can meet the requirements of different communication modes to provide effective data for the dispatching of the power system.
Based on the intelligent power saving device, as shown in fig. 2, the invention further provides a control method of the intelligent power saving device at the tail end of the power distribution network, which comprises the following steps:
1) setting parameters:
the capacity of the common compensation capacitor is Q1The capacity of the sub-compensation capacitor A, B, C is Q2-A、Q2-B、Q2-CThe rated phase voltage of the power grid is UNMaximum operating temperature T of the apparatusHMinimum operating temperature T of the apparatusLSwitching time interval t of equipment capacitor and highest phase current IH。
2) Acquiring real-time parameters:
the intelligent measurement and control unit reads the phase voltages of all phases of the power grid A, B, C through the ammeter and respectively obtains the phase voltages of the phases as UA、UB、UCPhase currents are respectively IA、IB、ICThe power factors are respectively pfA、pfB、pfCReactive power is respectively QA、QB、QCAnd acquiring the temperature T of the equipment.
3) Pre-judging:
if U isAOr UBOr UCGreater than 1.1UNOr U isAOr UBOr UCLess than 0.9UNOr T is greater than THOr T is less than TLOr IAOr IBOr ICIs greater than IHIf the judgment is not passed, the equipment cuts off all the capacitors and returns to the stepStep 2); otherwise, the pre-judgment is passed, and the step 4) is carried out.
4) Switching condition judgment:
4.1) if min { QA,QB,QCIs greater than Q1If the common compensation capacitor is not put into the capacitor, judging that the common compensation capacitor is put into the capacitor, and executing the step 5), otherwise, executing the next step;
4.2) if QAGreater than Q2-AIf the A phase of the sub-compensation capacitor is not input, judging that the A phase of the sub-compensation capacitor is input, and executing the step 5), otherwise, executing the next step;
4.3) if QBGreater than Q2-BAnd if the B phase of the sub-compensation capacitor is not put into the device, judging that the B phase of the sub-compensation capacitor is put into the device, and executing the step 5), otherwise, executing the next step;
4.4) if QCGreater than Q2-CAnd if the sub-compensation capacitor C phase is not put into the device, judging that the sub-compensation capacitor C phase is put into the device, and executing the step 5), otherwise, executing the next step;
4.5) if QAIf the phase A of the partial compensation capacitor is less than 0 and the phase A of the partial compensation capacitor is already put into the device, judging that the phase A of the partial compensation capacitor is cut off, and executing the step 6), otherwise, executing the next step;
4.6) if QBIf the phase number of the sub-compensation capacitor B is less than 0 and the phase number of the sub-compensation capacitor B is already input, judging to cut the phase number of the sub-compensation capacitor B, and executing the step 6), otherwise, executing the next step;
4.7) if QCIf the number of the phases is less than 0 and the sub-compensation capacitor C phase is already put into the device, judging to cut the sub-compensation capacitor C phase, and executing the step 6), otherwise, executing the next step;
4.8) if QA、QB、QCAre all smaller than 0, and the complementary capacitors are already put into use, the complementary capacitors are judged to be cut off, step 6) is executed, and otherwise, the step 2) is returned.
5) And when the preset switching interval time t is reached, switching the capacitor which is judged to be switched in the step 4) at the current zero crossing point, and executing the step 7).
6) When the preset switching interval time t is reached, cutting off the cut-off capacitor determined in the step 4) at the current zero crossing point, and executing the step 7).
7) The intelligent measurement and control unit uploads the action information of the capacitor and the currently acquired electrical parameters in the step 2) to an enterprise server through a wired or wireless network, and the step 2) is returned.
The above embodiments are only for illustrating the present invention, and the structure, the arrangement position and the steps of each component can be changed, and on the basis of the technical scheme of the present invention, the improvement and the equivalent transformation of the individual components and the steps according to the principle of the present invention should not be excluded from the protection scope of the present invention.

Claims (10)

1. The utility model provides a distribution network end intelligence power saving device which characterized in that: the intelligent measurement and control system comprises an air switch, an intelligent measurement and control unit, a first electronic switch circuit, a second electronic switch circuit and a capacitor;
one end of the air switch is connected with a low-voltage power grid, the other end of the air switch is connected with the intelligent measurement and control unit through the first electronic switch circuit and the second electronic switch circuit, and the first electronic switch circuit and the second electronic switch circuit are both connected with the capacitor; the intelligent measurement and control unit is supplied with power by the low-voltage power grid, receives the first electronic switch circuit, the second electronic switch circuit and the signals transmitted to by the capacitor, receives the electric quantity parameters transmitted to by the guide rail electricity meter connected with the low-voltage power grid, obtains the reactive demand and the control and protection parameters, outputs the control and protection signals to the first electronic switch circuit and the second electronic switch circuit to execute signal instructions, and completes the switching of the capacitor.
2. The intelligent power saving device of claim 1, wherein: the intelligent measurement and control unit is provided with a 485 bus interface for communication control.
3. The intelligent power saving device of claim 1, wherein: the guide rail ammeter is connected with the low-voltage power grid through a current transformer CT.
4. The intelligent power saving device of claim 1, wherein: the capacitor adopts a co-compensation capacitor with a built-in temperature sensor and each phase of series inductance, and a sub-compensation capacitor with a built-in temperature sensor and each phase of series inductance.
5. The intelligent power saving device of claim 4, wherein: the common compensation capacitor is a three-phase common compensation capacitor, and the sub-compensation capacitors are three-phase sub-compensation capacitors.
6. The intelligent power saving device of claim 4, wherein: the three-phase common compensation capacitor is connected with the first electronic switch circuit; the three-phase compensation capacitor is connected with the second electronic switch circuit.
7. The intelligent power saving device of claim 1, wherein: the intelligent measurement and control unit is provided with a touch screen, a communication interface and a control interface; and displaying the working state and the fault indication mark on the touch screen.
8. The intelligent power saving device of claim 1, wherein: the first electronic switch circuit and the second electronic switch circuit respectively comprise a zero-crossing trigger unit, a double-crystal thyristor, a high-power magnetic latching relay and a zero-crossing measurement and control overvoltage protection module; and after being connected in anti-parallel with the double crystal thyristors, the zero-crossing trigger unit is connected in parallel with the high-power magnetic latching relay and the zero-crossing measurement and control overvoltage protection module.
9. A control method based on the intelligent power saving device according to any one of claims 1 to 8, characterized by comprising the steps of:
1) setting parameters: the capacity of the common compensation capacitor is Q1The capacity of the sub-compensation capacitor A, B, C is Q2-A、Q2-B、Q2-CThe rated phase voltage of the power grid is UNMaximum operating temperature T of the apparatusHMinimum operating temperature T of the apparatusLSwitching time interval t of equipment capacitor and highest phase current IH；
2) Acquiring real-time parameters: the intelligent measurement and control unit reads the phase voltages of all phases of the power grid A, B, C through the ammeter and respectively obtains the phase voltages of the phases as UA、UB、UCPhase currents are respectively IA、IB、ICThe power factors are respectively pfA、pfB、pfCReactive power is respectively QA、QB、QCAcquiring the temperature T of the equipment;
3) pre-judging: if U isAOr UBOr UCGreater than 1.1UNOr U isAOr UBOr UCLess than 0.9UNOr T is greater than THOr T is less than TLOr IAOr IBOr ICIs greater than IHIf the judgment is not passed, the equipment cuts off all the capacitors and returns to the step 2); otherwise, the pre-judgment is passed, and the step 4) is carried out;
4) judging switching conditions;
5) when the preset switching interval time t is reached, switching the capacitor judged to be switched in the step 4) at the current zero crossing point, and executing the step 7);
6) when the preset switching interval time t is reached, cutting off the cut-off capacitor judged in the step 4) at the current zero crossing point, and executing the step 7);
7) the intelligent measurement and control unit uploads the action information of the capacitor and the currently acquired electrical parameters in the step 2) to an enterprise server through a wired or wireless network, and the step 2) is returned.
10. The control method according to claim 9, characterized in that: the switching conditions are judged as follows:
4.1) if min { QA,QB,QCIs greater than Q1If the common compensation capacitor is not put into the capacitor, judging that the common compensation capacitor is put into the capacitor, and executing the step 5), otherwise, executing the next step;
4.2) if QAGreater than Q2-AIf the A phase of the sub-compensation capacitor is not input, judging that the A phase of the sub-compensation capacitor is input, and executing the step 5), otherwise, executing the next step;
4.3) if QBGreater than Q2-BAnd if the B phase of the sub-compensation capacitor is not put into the device, judging that the B phase of the sub-compensation capacitor is put into the device, and executing the step 5), otherwise, executing the next step;
4.4) if QCGreater than Q2-CAnd if the sub-compensation capacitor C phase is not put into the device, judging that the sub-compensation capacitor C phase is put into the device, and executing the step 5), otherwise, executing the next step;
4.5) if QAIf the phase A of the partial compensation capacitor is less than 0 and the phase A of the partial compensation capacitor is already put into the device, judging that the phase A of the partial compensation capacitor is cut off, and executing the step 6), otherwise, executing the next step;
4.6) if QBIf the phase number of the sub-compensation capacitor B is less than 0 and the phase number of the sub-compensation capacitor B is already input, judging to cut the phase number of the sub-compensation capacitor B, and executing the step 6), otherwise, executing the next step;
4.7) if QCIf the number of the phases is less than 0 and the sub-compensation capacitor C phase is already put into the device, judging to cut the sub-compensation capacitor C phase, and executing the step 6), otherwise, executing the next step;
4.8) if QA、QB、QCAre all smaller than 0, and the complementary capacitors are already put into use, the complementary capacitors are judged to be cut off, step 6) is executed, and otherwise, the step 2) is returned.
CN202010000766.5A 2020-01-02 2020-01-02 Intelligent power saving device and method for tail end of power distribution network Pending CN111049141A (en)

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