CN212875397U - A pass through control circuit for unusual voltage - Google Patents
A pass through control circuit for unusual voltage Download PDFInfo
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- CN212875397U CN212875397U CN202021752501.2U CN202021752501U CN212875397U CN 212875397 U CN212875397 U CN 212875397U CN 202021752501 U CN202021752501 U CN 202021752501U CN 212875397 U CN212875397 U CN 212875397U
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Abstract
The utility model relates to the technical field of circuits, especially, relate to a pass through control circuit for unusual voltage. Be applied to power plant's unit, including first power and with at least one low-voltage inverter, wherein, still include: a second power supply; the input end of the first power supply loop is connected with a second power supply, and the output end of the first power supply loop is correspondingly connected with a low-voltage frequency converter through a contactor; the signal detection circuit is provided with a first relay, the first relay is coupled to a contactor corresponding to the first power supply circuit, and the contactor is closed when the signal detection circuit detects that the power supply fault of the low-voltage frequency converter is generated. Has the advantages that: the system can provide stable power for the auxiliary machine for 1 minute, avoid the problem of unplanned shutdown of the auxiliary machine and the blast furnace, bring a great economic loss problem to a thermal power plant, introduce no alternating current harmonic wave and save the cost.
Description
Technical Field
The utility model relates to the technical field of circuits, especially, relate to a pass through control circuit for unusual voltage.
Background
The frequency converter is generally applied to auxiliary machines such as a coal machine of a thermal power plant, but due to factors of unstable voltage of the power plant and a power grid, the frequency converter generates a low-voltage protection trip problem in use, the low-voltage protection trip can be represented as overcurrent protection or low-voltage protection due to different protection settings of the frequency converter, but is caused by low voltage of the power grid, wherein the factors causing the low voltage of the power grid comprise factors of power grid fluctuation, load imbalance, lightning stroke, power switching and the like on the main power grid side, factors of starting and applying large equipment on the load side, line overload and the like. However, the low-voltage protection tripping of the frequency converter causes the problem of unplanned shutdown of the auxiliary machine and the blast furnace, and great economic loss is brought to the thermal power plant.
In the prior art, a method for solving low-voltage protection tripping or low-voltage ride through is mainly to add an alternating-current uninterruptible power supply device to a frequency converter, directly provide a power supply for the frequency converter when the voltage of a power grid is abnormal, ensure that equipment overcomes the abnormal state of the voltage of the power grid within a certain time, ensure the normal operation of the frequency converter and reserve enough processing time for an upper system. However, the uninterruptible power supply device added in the prior art is small in capacity, low in conversion efficiency, high in protection level, high in investment cost and the like, so that a very small number of thermal power plants are used, and the uninterruptible power supply device adopts a series connection mode, so that harmonic waves are easily introduced, and the uninterruptible power supply device is not beneficial to stable operation of a frequency converter and auxiliary equipment. Therefore, the above technical problems are difficult problems to be solved by those skilled in the art.
Disclosure of Invention
In view of the above problems in the prior art, a ride-through control circuit for an abnormal voltage is provided.
The specific technical scheme is as follows:
the utility model provides a pass through control circuit for unusual voltage is applied to the unit of power plant, including a first power and with at least one low-voltage inverter that first power is connected, wherein, still include:
a second power supply;
the input end of the first power supply loop is connected with the second power supply, and the output end of the first power supply loop is correspondingly connected with the low-voltage frequency converter through a normally-open contactor;
at least one signal detection return circuit corresponds coupling respectively and is in one first power supply loop for detect coupling first power supply loop corresponds whether the low-voltage inverter produces power supply fault, every signal detection return circuit is provided with a first relay, first relay coupling is in first power supply loop corresponds the contactor, and in signal detection return circuit detects closed when the low-voltage inverter power supply fault the contactor.
Preferably, the low-voltage frequency converter is provided with two, and/or
The number of the first power supply loops is two.
Preferably, the first power supply loop includes a first voltage boosting unit, and the first voltage boosting unit boosts the voltage provided by the second power supply and inputs the boosted voltage to the corresponding low-voltage frequency converter.
Preferably, the power supply further comprises a switch power supply connected to the second power supply, an input end of the switch power supply is connected to the second power supply, and an output end of the switch power supply is connected to a second power supply loop, so that the second power supply is supplied with power to the second power supply loop after being subjected to voltage reduction.
Preferably, the signal detection circuit is connected in parallel to the second power supply circuit, and the signal detection circuit includes a low-voltage inverter control terminal and the first relay which are connected in series.
Preferably, the power supply system further comprises a fault detection circuit connected in parallel to the second power supply circuit, wherein the fault detection circuit is provided with a main controller and a second relay which are connected in series to detect whether the internal algorithm of the main controller has a fault or not, and the second relay is closed when the fault detection circuit detects that the internal algorithm of the main controller has the fault;
and the main controller is coupled to the low-voltage frequency converter.
Preferably, the power supply system further comprises a protection circuit connected in parallel to the second power supply circuit, and the protection circuit is provided with an upper protection device and a third relay which are connected in series;
the third relay is coupled with the main controller so as to transmit an upper protection signal to the main controller when the upper protection device generates the upper protection signal, so that the main controller disconnects the contactor.
Preferably, the method further comprises the following steps:
the input end of the first in-cabinet control loop is connected to the first power supply, and the output end of the first in-cabinet control loop is connected to an in-cabinet control power supply;
and the input end of the second in-cabinet control loop is connected to the second power supply, and the output end of the second in-cabinet control loop is connected to the in-cabinet control power supply.
Preferably, the first in-cabinet control loop includes a voltage reduction unit, and the voltage reduction unit reduces the voltage provided by the first power supply and inputs the reduced voltage to the corresponding in-cabinet control power supply.
Preferably, the second in-cabinet control circuit includes a second voltage boosting unit, and the second voltage boosting unit boosts the voltage provided by the second power supply and inputs the boosted voltage to the corresponding in-cabinet control power supply.
The technical scheme has the following advantages or beneficial effects: when detecting the low-voltage inverter that the power supply circuit that couples corresponds and producing power supply failure, contactor through closed power supply circuit corresponds to switch on power supply circuit and supply power to the low-voltage inverter, thereby can provide 1 minute's stabilized power for the auxiliary engine, thereby avoid the unplanned shutdown problem of auxiliary engine and blast furnace, and avoid bringing very big economic loss problem for thermal power plant, and be complete DC power supply transform, do not introduce the alternating current harmonic, also practice thrift the cost simultaneously.
Drawings
Embodiments of the present invention will now be described more fully hereinafter with reference to the accompanying drawings. The drawings are, however, to be regarded as illustrative and explanatory only and are not restrictive of the scope of the invention.
Fig. 1 is a schematic structural circuit diagram according to an embodiment of the present invention;
fig. 2 is a circuit diagram of the main controller controlling the first power supply to switch to the second power supply according to the embodiment of the present invention;
fig. 3 is a schematic circuit diagram of another structure according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that, in the present invention, the embodiments and features of the embodiments may be combined with each other without conflict.
The present invention will be further described with reference to the accompanying drawings and specific embodiments, but the present invention is not limited thereto.
The utility model provides a pass through control circuit for unusual voltage is applied to the unit of power plant, including a first power V1 and at least one low-voltage inverter VFD of being connected with first power V1, wherein, still include:
a second power source V2;
the input end of the power supply loop 1 is connected with a second power supply V2, and the output end of the power supply loop 1 is correspondingly connected with a low-voltage frequency converter VFD through a normally-open contactor MC;
at least one signal detection loop 2 is respectively and correspondingly coupled to a power supply loop 1, and is used for detecting whether a power supply fault occurs to a low-voltage frequency converter VFD corresponding to the coupled power supply loop 1, each signal detection loop 2 is provided with a first relay KA1, the first relay KA1 is coupled to a contactor MC corresponding to the power supply loop 1, and the contactor MC is closed when the signal detection loop 2 detects the power supply fault of the low-voltage frequency converter VFD.
Referring to fig. 1 and 2, in a situation where no power grid abnormality occurs in the thermal power plant, the first power supply V1 is used to supply power to the at least one low-voltage frequency converter VFD, and the first power supply V1 is also used as a factory ac 380V power supply, when abnormal voltage occurs in a power grid supplied by an auxiliary machine in the thermal power plant, that is, the factory ac 380V power supply cannot supply power to the at least one low-voltage frequency converter VFD, in this embodiment, the second power supply V2 is used, that is, a voltage of 200V in the factory dc power supply is used, and a voltage of 500V is input to the at least one low-voltage frequency converter VFD through the normally-open contactor MC, so that stable power can be provided for the auxiliary machine for 1 minute, thereby avoiding an unplanned shutdown problem of the auxiliary machine and the blast furnace, and avoiding a great economic loss problem to the thermal power plant.
Furthermore, in this embodiment, the power supply circuit 1 needs to detect in advance whether the low voltage inverter VFD corresponding to the power supply circuit 1 has a power supply failure through at least one signal detection circuit 2, namely, when the signal detection circuit 2 detects that the first power supply V1 supplies power to the low-voltage converter VFD abnormally, is coupled to the corresponding contactor MC of the power supply circuit 1 through each first relay KA1, thereby switching on the contactor MC, and switching on the power supply loop 1 to supply power to the low-voltage frequency converter VFD so as to provide stable power for 1 minute for the auxiliary machine, and each low-voltage inverter VFD can input 5KW of power to the LOAD connected, as shown in fig. 3, to avoid the problem of unplanned shutdown of the auxiliary machinery and the blast furnace, the problem of great economic loss brought to a thermal power plant is avoided, complete direct-current power supply conversion is achieved, alternating-current harmonic waves are not introduced, and meanwhile cost is saved. In addition, the time for switching from the first power source V1 to the second power source V2 is only within 30 ms.
In a preferred embodiment, two low-voltage frequency converters VFDs are provided, and/or
The power supply circuit 1 is provided in two.
Specifically, as shown in fig. 1, the low-voltage frequency converters VFD in the present embodiment may be provided in two, and the corresponding power supply loops 1 are also provided in two, so as to implement dual-path output of 500V voltage to each low-voltage frequency converter VFD, where each path can implement 5kw of power conversion.
In a preferred embodiment, the power supply circuit 1 includes a first voltage boosting unit 10, and the first voltage boosting unit 10 boosts the voltage provided by the second power source V2 and inputs the boosted voltage to the corresponding low-voltage inverter VFD.
Specifically, as shown in fig. 1, each power supply circuit 1 includes a first voltage boosting unit 10, and the 200V second power supply V2 is boosted by the first voltage boosting unit 10 and then input to the corresponding low-voltage inverter VFD.
In this embodiment, the first voltage boosting unit 10 employs a high-power DCDC conversion module for boosting the second power supply V2.
In a preferred embodiment, the power supply further comprises a switching power supply 3 connected to the second power supply V2, an input terminal of the switching power supply 3 is connected to the second power supply V2 source, and an output terminal of the switching power supply 3 is connected to a second power supply loop 4, so as to supply power to the second power supply loop 4 after the second power supply V2 is stepped down.
Specifically, as shown in fig. 2, in the present embodiment, a switching power supply 3 is provided to step down the 200V second power supply V2 to a voltage of 24V for supplying power to the second power supply loop 4.
In a preferred embodiment, the signal detection circuit 2 is connected in parallel to the second power supply circuit 4, and the signal detection circuit 2 includes a low voltage inverter control terminal 20 and a first relay KA1 connected in series.
Specifically, as shown in fig. 1, the switching power supply 3 in the above-described solution also supplies power to the signal detection circuit 2.
Further, after the operating signal of low-voltage inverter VFD was gathered to low-voltage inverter control end 20, in case find the grid voltage unusual, then first relay KA1 is closed, and then contactor MC among the above-mentioned technical scheme is closed to the realization is with second power V2 after stepping up input to low-voltage inverter VFD.
In a preferred embodiment, the power supply system further comprises a fault detection circuit 5 connected in parallel to the second power supply circuit 4, the fault detection circuit 5 is provided with a main controller U and a second relay KA2 connected in series to detect whether the internal algorithm of the main controller U fails, and the second relay KA2 is closed when the fault detection circuit 5 detects that the internal algorithm of the main controller U fails;
and the main controller U is coupled to the low-voltage inverter VFD.
Specifically, as shown in fig. 2, in the embodiment, the second relay KA2 is coupled to a fault lamp L, and when detecting that the internal algorithm of the main controller U has a fault, the second relay KA2 is closed, so that the fault lamp L is turned on, and at the same time, the main controller U opens the first relay KA1, so that the first power supply loop 1 is turned off to block the output of 500V voltage.
In a preferred embodiment, the power supply device further comprises a protection circuit 6 connected in parallel with the second power supply circuit 4, wherein the protection circuit 6 is provided with an upper protection device MFT and a third relay KA3 which are connected in series;
the third relay KA3 is coupled to the main controller U, and transmits an upper protection signal to the main controller U when the upper protection device MFT generates an upper protection signal, so that the main controller U opens the contactor MC.
Specifically, in this embodiment, when the power plant unit breaks down, upper protection device MFT can produce upper protection signal to transmit to main control unit U, and then make main control unit U disconnect contactor MC, in order to reach the output of blockading 500V voltage, thereby play the guard action.
In a preferred embodiment, the method further comprises:
a first in-cabinet control loop 7, wherein the input end of the first in-cabinet control loop 7 is connected to a first power supply V1, and the output end is connected to an in-cabinet control power supply V3;
and a second in-cabinet control loop 8, wherein the input end of the second in-cabinet control loop 8 is connected to the second power supply V2, and the output end is connected to the in-cabinet control power supply V3.
Specifically, as shown in fig. 1, the system further includes a first in-cabinet control loop 7 and a second in-cabinet control loop 8, both of which are connected to an in-cabinet control power supply V3, so that the in-cabinet control power supply V3 is powered on, and first, the devices in the cabinet, such as a fan and an illumination lamp, are powered on.
In this embodiment, when the grid voltage is not abnormal, the first power supply V1 supplies power to the in-cabinet control power supply V3, and when the grid voltage is abnormal, the second power supply V2 is switched to supply power to the in-cabinet control power supply V3.
In a preferred embodiment, the first in-cabinet control loop 7 includes a voltage-reducing unit 70, and the voltage-reducing unit 70 reduces the voltage provided by the first power source V1 and inputs the reduced voltage to the corresponding in-cabinet control power source V3.
Specifically, the in-cabinet control power V3 for supplying power to the fan and the lighting lamp requires 220V, and therefore, the 380V first power V1 needs to be stepped down, i.e., the first power V1 is connected to the step-down unit 70 through a node 71. In the present embodiment, the voltage dropping unit 70 includes a first breaker MCB1 and a transformer T, the first breaker MCB1 is connected to the first power source V1, and the transformer T is connected to the first breaker MCB 1.
Further, the in-cabinet control power supply V3 in this embodiment includes an in-cabinet fan power supply V31 and an in-cabinet lighting power supply V32 connected in parallel, wherein the transformer T is connected to the in-cabinet fan power supply V31 through a second circuit breaker MCB2, and the transformer T is connected to the in-cabinet lighting power supply V32 through a third circuit breaker MCB 3.
In a preferred embodiment, the second in-cabinet control circuit 8 includes a second voltage boosting unit 80, and the second voltage boosting unit 80 boosts the voltage provided by the second power source V2 and inputs the boosted voltage to the corresponding in-cabinet control power source V3.
Specifically, in the present embodiment, the second voltage boosting unit 80 includes a first fuse FU1 and a fourth circuit breaker MCB4 serially connected in sequence between the second power supply V2 and the in-cabinet control power supply V3, so as to boost the second power supply V2 of 200V and supply power to the in-cabinet control power supply V3.
In a preferred embodiment, as shown in fig. 1, each first power supply circuit 1 further comprises a fifth circuit breaker MCB5 connected between the second power source V2 and the first booster cell 10.
In a preferred embodiment, a sixth circuit breaker MCB6 and a second fuse FU2 are further included between each contactor MC and each low voltage inverter VFD.
In a preferred embodiment, a seventh circuit breaker MCB7 is further included between each low voltage inverter VFD and the first power source V1.
In a preferred embodiment, an eighth chopper MCB8 is also connected between the first source V1 and the first node 71.
The above description is only an example of the preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and those skilled in the art should be able to realize the equivalent alternatives and obvious variations of the present invention.
Claims (10)
1. The utility model provides a pass through control circuit for unusual voltage is applied to the unit of power plant, including a first power and with at least one low-voltage inverter that first power is connected, its characterized in that still includes:
a second power supply;
the input end of the first power supply loop is connected with the second power supply, and the output end of the first power supply loop is correspondingly connected with the low-voltage frequency converter through a normally-open contactor;
at least one signal detection return circuit corresponds coupling respectively and is in one first power supply loop for detect coupling first power supply loop corresponds whether the low-voltage inverter produces power supply fault, every signal detection return circuit is provided with a first relay, first relay coupling is in first power supply loop corresponds the contactor, and in signal detection return circuit detects closed when the low-voltage inverter power supply fault the contactor.
2. The ride-through control circuit of claim 1, wherein the low voltage frequency converter is provided in two, and/or
The number of the first power supply loops is two.
3. The ride-through control circuit of claim 1, wherein the first power supply loop comprises a first voltage boosting unit, and the first voltage boosting unit boosts the voltage provided by the second power supply and inputs the boosted voltage to the corresponding low-voltage inverter.
4. The ride-through control circuit of claim 1, further comprising a switching power supply coupled to the second power supply, wherein an input of the switching power supply is coupled to the second power supply, and an output of the switching power supply is coupled to a second power supply loop, such that the second power supply is stepped down to supply power to the second power supply loop.
5. The ride-through control circuit of claim 4, wherein the signal detection loop is connected in parallel with the second power supply loop, and the signal detection loop comprises a low voltage inverter control terminal and the first relay connected in series.
6. The ride-through control circuit of claim 4, further comprising a fault detection circuit connected in parallel to the second power supply circuit, the fault detection circuit being provided with a main controller and a second relay connected in series to detect whether the internal algorithm of the main controller fails, the second relay being closed when the fault detection circuit detects a failure of the internal algorithm of the main controller;
and the main controller is coupled to the low-voltage frequency converter.
7. The ride-through control circuit of claim 6, further comprising a protection circuit connected in parallel to the second power supply circuit, wherein the protection circuit is provided with an upper protection device and a third relay connected in series;
the third relay is coupled with the main controller so as to transmit an upper protection signal to the main controller when the upper protection device generates the upper protection signal, so that the main controller disconnects the contactor.
8. The ride-through control circuit of claim 1, further comprising:
the input end of the first in-cabinet control loop is connected to the first power supply, and the output end of the first in-cabinet control loop is connected to an in-cabinet control power supply;
and the input end of the second in-cabinet control loop is connected to the second power supply, and the output end of the second in-cabinet control loop is connected to the in-cabinet control power supply.
9. The ride-through control circuit of claim 8, wherein the first in-cabinet control loop comprises a voltage-dropping unit, and the voltage-dropping unit drops the voltage provided by the first power supply and inputs the voltage to the corresponding in-cabinet control power supply.
10. The ride-through control circuit of claim 8, wherein the second in-cabinet control loop comprises a second voltage boosting unit, and the second voltage boosting unit boosts the voltage provided by the second power supply and inputs the boosted voltage to the corresponding in-cabinet control power supply.
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| CN202021752501.2U CN212875397U (en) | 2020-08-20 | 2020-08-20 | A pass through control circuit for unusual voltage |
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| CN202021752501.2U CN212875397U (en) | 2020-08-20 | 2020-08-20 | A pass through control circuit for unusual voltage |
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| CN212875397U true CN212875397U (en) | 2021-04-02 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112134276A (en) * | 2020-08-20 | 2020-12-25 | 上海电气富士电机电气技术有限公司 | A pass through control circuit for unusual voltage |
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2020
- 2020-08-20 CN CN202021752501.2U patent/CN212875397U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112134276A (en) * | 2020-08-20 | 2020-12-25 | 上海电气富士电机电气技术有限公司 | A pass through control circuit for unusual voltage |
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