CN110261689B - Relay detection method for photovoltaic inverter BUS voltage unbalance and live wire grounding - Google Patents
Relay detection method for photovoltaic inverter BUS voltage unbalance and live wire grounding Download PDFInfo
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
- G01R19/16576—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing DC or AC voltage with one threshold
- G01R19/1658—AC voltage or recurrent signals
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R29/16—Measuring asymmetry of polyphase networks
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
- G01R31/3277—Testing of circuit interrupters, switches or circuit-breakers of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches
- G01R31/3278—Testing of circuit interrupters, switches or circuit-breakers of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches of relays, solenoids or reed switches
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Abstract
The invention discloses a relay detection method when the voltage of a photovoltaic inverter BUS is unbalanced and a live wire is grounded. It includes: s1, disconnecting all relays; s2, closing the main relay and simultaneously injecting open-loop voltage; s3, assuming that one phase is grounded, constructing a power grid sequence to enable the voltage of the grounded phase to be zero to obtain the voltage of the other two phases, and obtaining zero sequence voltage through the three-phase voltage during grounding; s4, respectively calculating the duty ratio of each switching voltage; s5, calculating three-phase separation zero sequence voltage under the condition of BUS unbalance, and obtaining a corresponding effective value by calculating the root mean square value of the three-phase separation zero sequence voltage; s6, judging whether the inversion voltage is larger than or equal to the effective value of the grounding phase obtained in the step S5, if so, completely sticking the main relay of the phase with the live wire connected with the ground; and if not, the main relay of the phase is not closed.
Description
Technical Field
The invention belongs to the field of photovoltaic inverters, and relates to a relay detection method of a photovoltaic inverter when the BUS voltage is unbalanced and a live wire is grounded.
Background
When the existing photovoltaic inverter is normally and effectively grounded, the N point and the PE point are in an equipotential state, and the three-phase live wire voltage of the inverter is almost equal. However, in some rural power systems, because power equipment is low, a simple outdoor equipment transformer is basically adopted, and after a long time, the transformer is aged and has poor insulation performance, so that a short circuit occurs between a certain phase live wire and PE, and at the moment, a certain voltage difference exists between the potential of the N point and the potential of the PE point, and the working state of the inverter is directly influenced by the voltage difference.
If the power grid contains direct current components, the output current is biased in a certain direction at the moment, and the voltage of the BUS is unbalanced. For this phenomenon, the commonly used method can be balanced by compensating for dead-zone turn-on and turn-off times. Under some extreme conditions, for example, when the live wire is grounded, the BUS voltage imbalance may bring great influence to the control inversion voltage, thereby influencing the logic judgment of the relay.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a relay detection method for photovoltaic inverter when the voltage of a BUS is unbalanced and a live wire is grounded.
In order to achieve the purpose, the invention adopts the technical scheme that:
a relay detection method for a photovoltaic inverter when the voltage of a BUS is unbalanced and a live wire is grounded is characterized in that the inverter is connected to an R-phase end of a three-phase power grid sequentially through an R-phase main relay and an auxiliary relay, the inverter is connected to an S-phase end of the three-phase power grid sequentially through an S-phase main relay and an auxiliary relay, and the inverter is connected to a T-phase end of the three-phase power grid sequentially through a T-phase main relay and an auxiliary relay;
the relay fault detection method comprises the following steps:
s1, disconnecting all the main relays and the auxiliary relays;
s2, closing the R-phase main relay, the S-phase main relay and the T-phase main relay, and simultaneously and respectively injecting corresponding open-loop voltages into the three main relays;
s3, assuming that one phase is grounded, enabling the voltage of the grounded phase to be zero by constructing a power grid sequence, obtaining the voltages of the other two phases when a live wire is grounded, and obtaining a zero sequence voltage by the three-phase voltage when the live wire is grounded;
s4, calculating the duty of each switching voltage;
s5, calculating three-phase separation zero sequence voltage under the condition of BUS unbalance, and obtaining a corresponding effective value by calculating the root mean square value of the three-phase separation zero sequence voltage;
s6, judging whether the inversion voltage is larger than or equal to the effective value of the grounding phase obtained in the step S5, if so, completely sticking the main relay of the phase with the live wire connected with the ground; and if not, the main relay of the phase is not closed.
Preferably, in step S2, the open-loop voltage corresponding to R phase is Asin (wt), the open-loop voltage corresponding to S phase is Asin (wt +2/3 pi), and the open-loop voltage corresponding to T phase is Asin (wt +4/3 pi), where a is the peak voltage.
More preferably, the three-phase grid voltage is respectively recorded as: r ═ Bsin (wt), S ═ Bsin (wt +2/3 pi), T ═ Bsin (wt +4/3 pi), where B is the peak voltage;
in step S3, assuming that the R-phase line is grounded, and constructing the grid sequence C so that C + bsin (wt) becomes 0, the three-phase voltages when the line is grounded are: r1 ═ 0; s1 ═ Bsin (wt +2/3 pi) + C; t1 ═ Bsin (wt +4/3 pi) + C;
through new three-phase voltages R1, S1 and T1, zero-sequence voltage N is obtained as (R1+ S1+ T1)/3.
Further, in step S4, the duty ratios of the open-loop voltage dutyl r ═ Asin (wt)/(1/2 ×, duty S ═ Asin (wt +2/3 pi)/(1/2 ×, BUS), dutyl t ═ Asin (wt +4/3 pi)/(1/2 ×, BUS) are calculated, respectively.
Further, in step S5, calculating isolated zero sequence voltages Rinv ═ dutyR (1/2 × BUS + Delta) -N, Sinv ═ dutyS (1/2 × BUS + Delta) -N, Tinv ═ dutyT (1/2 × BUS + Delta) -N, and calculating root mean square values of the three to obtain corresponding effective values RinvRms, SinvRms, TinvRms, wherein BUS is BUS voltage, and Delta is BUS voltage imbalance;
in the step S6, the inversion voltage is greater than or equal to RinvRms, which indicates that the main relay of the R phase connected with the live wire is completely stuck; and the inversion voltage is less than RinvRms, which indicates that the main relay of the R phase connected with the live wire is not closed.
Furthermore, in step S3, assuming that the S-phase or T-phase live wire is grounded, the subsequent steps are repeated, and in step S6, it is determined whether the S-phase main relay or the T-phase main relay is stuck or not.
Preferably, in step S6, the inverter voltage is a sampled value of a voltage between the corresponding main relay and the sub relay.
Compared with the prior art, the invention has the following advantages by adopting the scheme:
according to the relay detection method provided by the invention, under the conditions of unbalanced BUS voltage and grounding of a live wire, the fault of the relay can be accurately judged according to different BUS unbalance degrees, such as whether the relay of a certain phase is completely bonded or not closed.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a schematic diagram of a hardware system to which a relay detection method of an embodiment is applied;
FIG. 2 is a flow chart of a relay detection method of an embodiment;
FIG. 3 is a C sequence of three phase waveforms and configurations after the R phase is grounded;
FIG. 4 is a three-phase waveform separating zero sequences;
FIG. 5 is an inverted voltage with a zero sequence;
FIG. 6 shows the inverter voltage of the isolated zero sequence with BUS balance;
fig. 7 is a diagram of an inverted voltage distribution, where BUS is 640V and Delta is 40V.
Detailed Description
Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the advantages and features of the invention may be more readily understood by those skilled in the art. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Fig. 1 shows a relay between a photovoltaic inverter and a three-phase grid. As shown in fig. 1, the inverter is connected to the R-phase end of the three-phase power grid through the R-phase main relay and the auxiliary relay in sequence, the inverter is connected to the S-phase end of the three-phase power grid through the S-phase main relay and the auxiliary relay in sequence, and the inverter is connected to the T-phase end of the three-phase power grid through the T-phase main relay and the auxiliary relay in sequence.
The detection of the invention is based on the following:
under the condition of BUS voltage balance, after the relay is normally closed
Inverted voltage Vinv＝Sin(wt)*PBusOr Vinv＝Sin(wt)*NBus
That is, V can be described by a formulainv＝{Sin(wt)*PBus,Sin(wt)*NBus}
In the case of BUS voltage imbalance, the above equation may be described as
VinvSin (wt) 1/2(BUS + Delta), sin (wt) 1/2(BUS-Delta) in a functional relationship with BUS voltage magnitude and Delta value, where Delta | PBus-NBusL, wherein P Bus1/2(BUS + Delta), N Bus1/2 (BUS-Delta). Delta magnitude directly reflects the degree of BUS voltage imbalance.
The embodiment provides a relay fault detection method, which comprises the following steps:
s1, disconnecting all the main relays and the auxiliary relays;
s2, closing the R-phase main relay, the S-phase main relay and the T-phase main relay, and simultaneously and respectively injecting corresponding open-loop voltages into the three main relays;
s3, assuming that one phase is grounded, enabling the voltage of the grounded phase to be zero by constructing a power grid sequence, obtaining the voltages of the other two phases when a live wire is grounded, and obtaining a zero sequence voltage by the three-phase voltage when the live wire is grounded;
s4, calculating the duty of each switching voltage;
s5, calculating three-phase separation zero sequence voltage under the condition of BUS unbalance, and obtaining a corresponding effective value by calculating the root mean square value of the three-phase separation zero sequence voltage;
s6, judging whether the inversion voltage is larger than or equal to the effective value of the grounding phase obtained in the step S5, if so, completely sticking the main relay of the phase with the live wire connected with the ground; and if not, the main relay of the phase is not closed. The inverter voltage is a sampling value of the voltage between the main relay and the auxiliary relay of the corresponding phase.
In a more preferred embodiment, the steps S3-S6 are repeatedly executed until the judgment of the three-phase main relay is completed.
Specifically, as shown in fig. 2, a specific flow of the relay detection method is as follows:
starting;
grid connection self-checking;
disconnecting the three-phase main relay and the three-phase auxiliary relay;
closing the three-phase main relay, and simultaneously injecting open-loop voltage into the three-phase main relay respectively, wherein the open-loop voltage corresponding to the R phase is Asin (wt), the open-loop voltage corresponding to the S phase is Asin (wt +2/3 pi), and the open-loop voltage corresponding to the T phase is Asin (wt +4/3 pi); assuming that the switching frequency is K (Hz) and the sampling period is T (ms), T/(1/K) points are needed to be sampled in the sampling period; the three-phase grid voltage is respectively recorded as: r ═ Bsin (wt), S ═ Bsin (wt +2/3 pi), T ═ Bsin (wt +4/3 pi);
assuming that an R-phase live line is grounded, constructing a grid sequence C so that C + bsin (wt) ═ 0, the three-phase voltages when the live line is grounded are: r1 ═ 0; s1 ═ Bsin (wt +2/3 pi) + C; t1 ═ Bsin (wt +4/3 pi) + C; obtaining zero-sequence voltage N ═ 3 (R1+ S1+ T1)/3 through new three-phase voltages R1, S1 and T1;
separately calculating the duty of the open-loop voltageR＝Asin(wt)/(1/2*BUS)，dutyS＝Asin(wt+2/3π)/(1/2*BUS)，dutyT＝Asin(wt+4/3π)/(1/2*BUS)；
Calculating separated zero sequence voltage R under the condition of BUS unbalanceinv＝dutyR*(1/2*BUS+Delta)-N，Sinv＝dutyS*(1/2*BUS+Delta)-N，Tinv＝dutyT(1/2 BUS + Delta) -N, and calculating the RMS values of the three to obtain the corresponding effective value RinvRms，SinvRms，TinvRms；
Judging whether the inversion voltage of the R phase is more than or equal to RinvRmsThe fact that the fire wire is connected with the underground R-phase main relay is completely stuck is described; the inversion voltage is less than RinvRmsAnd the situation that the main relay of the R phase connected with the live wire and the ground is not closed is explained.
For example, if the switching frequency is 16K and the sampling period is 20ms, 320 points are needed for a single period; the voltage of the power grid is 230V, and the open-loop voltage is 90V. Wherein, the three-phase waveform after the grounding of the R phase and the formed C sequence are shown in figure 3, the three-phase waveform with separated zero sequence is shown in figure 4, the inversion voltage with zero sequence is shown in figure 5, and the inversion voltage with separated zero sequence under the balance of the BUS is shown in figure 6. Fig. 7 shows the inverted voltage distribution when BUS is 640V and Delta is 40V.
The above embodiments are merely illustrative of the technical ideas and features of the present invention, and are preferred embodiments, which are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (6)
1. A relay detection method for photovoltaic inverter bus voltage unbalance and live wire grounding is characterized in that an inverter is connected to an R phase end of a three-phase power grid sequentially through an R phase main relay and an auxiliary relay, the inverter is connected to an S phase end of the three-phase power grid sequentially through an S phase main relay and an auxiliary relay, and the inverter is connected to a T phase end of the three-phase power grid sequentially through a T phase main relay and an auxiliary relay;
the relay fault detection method is characterized by comprising the following steps:
s1, disconnecting all the main relays and the auxiliary relays;
s2, closing the R-phase main relay, the S-phase main relay and the T-phase main relay, and simultaneously and respectively injecting corresponding open-loop voltages into the three main relays;
s3, assuming that one phase is grounded, enabling the voltage of the grounded phase to be zero by constructing a power grid sequence, obtaining the voltages of the other two phases when a live wire is grounded, and obtaining a zero sequence voltage by the three-phase voltage when the live wire is grounded;
s4, respectively calculating the duty of each open-loop voltage;
s5, calculating three-phase separation zero sequence voltage under the condition of unbalanced bus voltage, and obtaining a corresponding effective value by calculating the root mean square value of the three-phase separation zero sequence voltage;
s6, judging whether the inversion voltage is larger than or equal to the effective value of the grounding phase obtained in the step S5, if so, completely sticking the main relay of the phase with the live wire connected with the ground; if not, the main relay of the phase is not closed; and the inversion voltage is a sampling value of the voltage between the main relay and the auxiliary relay of the corresponding phase.
2. The relay detection method according to claim 1, wherein in step S2, the open-loop voltage corresponding to R phase is Asin (wt), the open-loop voltage corresponding to S phase is Asin (wt +2/3 pi), and the open-loop voltage corresponding to T phase is Asin (wt +4/3 pi), where a is a peak voltage.
3. The relay detection method according to claim 2, wherein the three-phase grid voltage is respectively recorded as: r = Bsin (wt), S = Bsin (wt +2/3 pi), T = Bsin (wt +4/3 pi), wherein B is the peak voltage;
in step S3, assuming that the R-phase live line is grounded, constructing the grid sequence C such that C + bsin (wt) =0, the three-phase voltages when the live line is grounded are: r1= 0; s1= Bsin (wt +2/3 pi) + C; t1= Bsin (wt +4/3 pi) + C;
through new three-phase voltages R1, S1 and T1, zero-sequence voltage N = (R1+ S1+ T1)/3 is obtained.
4. The relay detection method according to claim 3, wherein in step S4, duty of the open-loop voltage is calculated respectivelyR=Asin(wt)/(1/2*BUS)，dutyS=Asin(wt+2/3π)/(1/2*BUS)，dutyT= Asin (wt +4/3 pi)/(1/2 BUS), BUS being the BUS voltage.
5. Relay inspection according to claim 4The measuring method is characterized in that in step S5, the separated zero sequence voltage R under the condition of unbalanced bus voltage is calculatedinv=dutyR*(1/2*BUS+Delta)-N，Sinv=dutyS *(1/2*BUS+Delta)-N，Tinv=dutyT(1/2 BUS + Delta) -N, and calculating the RMS values of the three to obtain the corresponding effective value RinvRms，SinvRms，TinvRmsWherein BUS is BUS voltage, and Delta is the unbalance degree of the BUS voltage;
in step S6, the inversion voltage is greater than or equal to RinvRmsThe fact that the fire wire is connected with the underground R-phase main relay is completely stuck is described; the inversion voltage is less than RinvRmsAnd the situation that the main relay of the R phase connected with the live wire and the ground is not closed is explained.
6. The relay detection method according to claim 3, characterized in that: in step S3, assuming that the S-phase or T-phase live wire is grounded, the subsequent steps are repeated, and in step S6, it is determined whether the live wire is grounded or not, respectively, the S-phase main relay or the T-phase main relay is stuck or not.
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| CN112858898B (en) * | 2021-01-07 | 2023-04-04 | 上海新时达电气股份有限公司 | Relay fault detection method |
| CN112986809B (en) * | 2021-01-27 | 2022-11-18 | 苏州海鹏科技有限公司 | Relay detection circuit suitable for photovoltaic inverter and detection method thereof |
| CN112986813B (en) * | 2021-03-05 | 2023-03-21 | 苏州海鹏科技有限公司 | Relay detection circuit and detection method of single-phase grid-connected photovoltaic inverter |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102565691A (en) * | 2011-12-14 | 2012-07-11 | 广州三晶电气有限公司 | Relay failure detection device and method for grid-connected inverter |
| KR20130039817A (en) * | 2011-10-13 | 2013-04-23 | 에스케이이노베이션 주식회사 | Circuit for monitoring relay |
| CN103852691A (en) * | 2012-12-06 | 2014-06-11 | 施耐德电器工业公司 | Directional detection of a fault in a network of a grounding system with compensated or insulated neutral point |
| CN107505533A (en) * | 2017-09-14 | 2017-12-22 | 艾思玛新能源技术（扬中）有限公司 | The live wire earth-fault detecting method and sampled signal processing method of combining inverter |
| CN107957546A (en) * | 2017-11-16 | 2018-04-24 | 阳光电源股份有限公司 | A kind of detection method and equipment of grid-connected inverters AC relay |
| CN207965070U (en) * | 2018-01-12 | 2018-10-12 | 江苏南瑞泰事达电气有限公司 | A kind of detection device of three-phase current unbalance regulating device |
| EP3396692A1 (en) * | 2017-04-27 | 2018-10-31 | Rockwell Automation Asia Pacific Business center Pte. Ltd. | Electrical relay system with failure detection |
| CN109188278A (en) * | 2018-09-27 | 2019-01-11 | 中车大连机车车辆有限公司 | Three-phase imbalance detection circuit and system |
| CN109375099A (en) * | 2018-10-19 | 2019-02-22 | 艾思玛新能源技术（扬中）有限公司 | A kind of fault detection method of photovoltaic inverter grid-connected relay |
-
2019
- 2019-06-26 CN CN201910558360.6A patent/CN110261689B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20130039817A (en) * | 2011-10-13 | 2013-04-23 | 에스케이이노베이션 주식회사 | Circuit for monitoring relay |
| CN102565691A (en) * | 2011-12-14 | 2012-07-11 | 广州三晶电气有限公司 | Relay failure detection device and method for grid-connected inverter |
| CN103852691A (en) * | 2012-12-06 | 2014-06-11 | 施耐德电器工业公司 | Directional detection of a fault in a network of a grounding system with compensated or insulated neutral point |
| EP3396692A1 (en) * | 2017-04-27 | 2018-10-31 | Rockwell Automation Asia Pacific Business center Pte. Ltd. | Electrical relay system with failure detection |
| CN107505533A (en) * | 2017-09-14 | 2017-12-22 | 艾思玛新能源技术（扬中）有限公司 | The live wire earth-fault detecting method and sampled signal processing method of combining inverter |
| CN107957546A (en) * | 2017-11-16 | 2018-04-24 | 阳光电源股份有限公司 | A kind of detection method and equipment of grid-connected inverters AC relay |
| CN207965070U (en) * | 2018-01-12 | 2018-10-12 | 江苏南瑞泰事达电气有限公司 | A kind of detection device of three-phase current unbalance regulating device |
| CN109188278A (en) * | 2018-09-27 | 2019-01-11 | 中车大连机车车辆有限公司 | Three-phase imbalance detection circuit and system |
| CN109375099A (en) * | 2018-10-19 | 2019-02-22 | 艾思玛新能源技术（扬中）有限公司 | A kind of fault detection method of photovoltaic inverter grid-connected relay |
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