CN103529335A - Low voltage ride through detection device for grid connection photovoltaic inverter - Google Patents
Low voltage ride through detection device for grid connection photovoltaic inverter Download PDFInfo
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Abstract
The invention provides a low voltage ride through detection device for a grid connection photovoltaic inverter. The device comprises a voltage division and adjustment module, a circuit breaker C1, a circuit breaker C2, a circuit breaker C4 and a short-circuit fling-cut switch, wherein the two ends of a voltage transformer are connected with a power grid respectively and connected with the voltage division and adjustment module through the circuit breaker C1; a neutral point of the voltage transformer, the short-circuit fling-cut switch, the circuit breaker C4 and the voltage division and adjustment module are connected in sequence; the voltage division and adjustment module is connected with the photovoltaic inverter through the circuit breaker C2. According to the device, the switch is skillfully used, so that the number of electric reactors can be reduced; the detected inverter does not need to be halted in a drop amplitude switching process, so that the detection time is shortened and the efficiency is improved.
Description
Technical field
The present invention relates to a kind of pick-up unit of field of photovoltaic power generation, specifically relate to a kind of low voltage crossing pick-up unit of grid-connected photovoltaic inverter.
Background technology
Along with photovoltaic generation proportion in electric power energy is increasing, photovoltaic generating system can not be ignored the impact of electrical network.Especially in the western Gansu of China, Qinghai one, be with, photovoltaic generating system adopts the extensive mode of access of concentrating to be connected to the grid.When electrical network breaks down while causing grid-connected point voltage to fall, once the large-scale off-grid of photo-voltaic power generation station may cause the collapse of line voltage and frequency, have a strong impact on the safe and stable operation of electrical network, so large-sized photovoltaic power station must have low voltage ride-through capability.
In standard GB/T/T19964-2012 that 2012 Nian， China promulgate " photo-voltaic power generation station access power system technology regulation ", there is clearly regulation: when the grid-connected point voltage of photo-voltaic power generation station falls to the curve 1 of Fig. 1 when following, photo-voltaic power generation station can cut out from electrical network; The grid-connected point voltage of photo-voltaic power generation station is when curve 1 is above, and photo-voltaic power generation station should guarantee that off-grid does not move continuously.
Different from wind power generation plant, the function of photovoltaic system low voltage crossing is realized by photovoltaic DC-to-AC converter completely.Therefore need relevant checkout equipment to detect the ability of inverter low voltage crossing.Pick-up unit generally adopts passive reactance device ground short circuit or phase fault to carry out simulating grid fault, as shown in Fig. 2 low voltage crossing pick-up unit schematic diagram.
Reactor X in figure
1, X
2be air reactor, reactor X
1for current limiting reactor, it is the impact on higher level's electrical network during for restraint device short circuit; X
1tend to be parallel with by-pass switch.X
2for short-circuit reactance device.While detecting photovoltaic DC-to-AC converter, first disconnect S
1, drop into current limiting reactor; Then closed S
2, dropping into short-circuit reactance device, voltage during simulating grid fault falls.The number percent that voltage falls meets following formula:
z in formula
1, Z
2be respectively reactor X
1, X
2resistance value, Z
kequiva lent impedance for electrical network.
Traditional wind electric converter or photovoltaic DC-to-AC converter low voltage crossing pick-up unit, all adopt the reactor of a plurality of not same feeling values to form different parameters X by connection in series-parallel array mode
1, X
2thereby the voltage of simulation different depth falls, there is following shortcoming in pick-up unit:
(1) much more as far as possible according to the regulation of be correlated with both at home and abroad photovoltaic and wind-electricity integration standard, low voltage crossing pick-up unit falls a little should be at least 5 points, fall a little and should and be evenly distributed.But because pick-up unit cannot configure a lot of reactors, or be subject to the restriction of reactor number of taps, pick-up unit cannot be realized and fall amplitude more.
(2), when needs switched voltage falls amplitude, must switch reactor connected mode or switch the different taps of reactor, general employing manually and automatic two kinds of modes:
Adopt manual mode to change the reactor parameter of major loop, complex steps, length consuming time, has certain potential safety hazard, be unfavorable for that the voltage of realizing fast multiple amplitude and form falls, but relative cost is lower, and floor area is little.
Adopt automatic mode to change major loop reactor parameter, generally adopt the mode of thyristor or Circuit Breaker Switching to realize the switching of reactor tap, installation cost is very high, and floor area is large.
(3) be no matter that manual modification, isolating switch switch or the mode of thuristor throw-in and throw-off, changing all needs while falling amplitude that tested photovoltaic DC-to-AC converter is out of service just can be operated afterwards, has increased extra detection time, is unfavorable for the raising of whole detection efficiency.
Summary of the invention
For overcoming above-mentioned the deficiencies in the prior art, the invention provides a kind of low voltage crossing pick-up unit of grid-connected photovoltaic inverter, the core of this device is for being used the transformer dividing potential drop by-pass cock using for transmitting transformer tap changing (include and carry dividing potential drop by-pass cock and unloaded tap changer).This switch of ingenious use, not only can reduce the quantity of reactor; While falling amplitude switching, tested inverter, without shutdown, has reduced detection time, has improved efficiency.Meanwhile, the cost of transformer dividing potential drop by-pass cock (include and carry dividing potential drop by-pass cock and no-load dividing potential drop by-pass cock) is more much lower than the cost of primary cut-out and thuristor throw-in and throw-off switch, floor area is also little, the holistic cost and the floor area that have reduced to a certain extent whole device, promoted the sound development of photovoltaic industry.
Realizing the solution that above-mentioned purpose adopts is:
A low voltage crossing pick-up unit, its improvements are: described device comprises a minute voltage regulation module, isolating switch C1, isolating switch C2, isolating switch C4 and short circuit fling-cut switch;
Transformer two ends connect with electrical network respectively and are connected with described minute voltage regulation module by described isolating switch C1; The neutral point of described transformer, described short circuit fling-cut switch, described isolating switch C4 and described minute voltage regulation module are connected successively; Within described minute, voltage regulation module is connected with photovoltaic DC-to-AC converter by described isolating switch C2.
Further, described minute voltage regulation module comprises transformer dividing potential drop by-pass cock WL2, N reactor L(N >=3 of connecting successively) and transformer dividing potential drop by-pass cock WL3; Described reactor is multitap reactor, and described transformer dividing potential drop by-pass cock WL2 controls respectively with WL3 the described reactor L being connected;
The gear end of transformer dividing potential drop by-pass cock WL4 is connected to the zero-span end of described transformer dividing potential drop by-pass cock WL3 and reactor between any two, the zero-span end of described transformer dividing potential drop by-pass cock WL4 by isolating switch C2 and isolating switch C3 respectively be connected described photovoltaic DC-to-AC converter and be connected with the zero-span end of transformer dividing potential drop by-pass cock WL1;
Described isolating switch C4 is connected with the zero-span end of transformer dividing potential drop by-pass cock WL5 with transformer dividing potential drop by-pass cock WL1 respectively with described isolating switch C1;
A gear of described transformer dividing potential drop by-pass cock WL1 and described transformer dividing potential drop by-pass cock WL5 and two gear cross connections; The zero-span end of described transformer dividing potential drop by-pass cock WL2 and transformer dividing potential drop by-pass cock WL3 is connected with two gear ends with a gear end of described transformer dividing potential drop by-pass cock WL1 respectively.
Further, the zero-span of described transformer dividing potential drop by-pass cock WL1 and WL5 is connected respectively described isolating switch C1 and described isolating switch C4, a gear of described transformer dividing potential drop by-pass cock WL1 and WL5 and two gear cross connections.
Further, described transformer dividing potential drop by-pass cock WL1 and described transformer dividing potential drop by-pass cock WL5 are the by-pass cock of two gears, and described transformer dividing potential drop by-pass cock WL1 is the switch of the identical gear of while switching with described transformer dividing potential drop by-pass cock WL5;
The gear number of described transformer dividing potential drop by-pass cock WL2 and WL3 is corresponding with the tap number of reactor;
The gear number of described transformer dividing potential drop by-pass cock WL4 equates with reactor number;
The transformer dividing potential drop by-pass cock that described short circuit fling-cut switch is ten gears.
Further, described isolating switch C1, described isolating switch C2 and described isolating switch C4 are AC circuit breaker; Described isolating switch C4 is short interruption device.
Further, described isolating switch C3 is AC circuit breaker; Described isolating switch C3 is bypass breaker.
Further, described reactor is the node voltage access photovoltaic DC-to-AC converter of the zero-span end of node voltage and described transformer dividing potential drop by-pass cock WL4 between any two, realizes the line short fault simulation of different voltage magnitudes.
Further, described transformer dividing potential drop by-pass cock WL2 and described transformer dividing potential drop by-pass cock WL3 are for switching the reactor tap that drops into circuit;
Described reactor tap is more, and the gear of the transformer dividing potential drop by-pass cock needing is just more, falls a little just manyly, and the distribution in voltage range is more even.
Further, described transformer dividing potential drop by-pass cock includes and carries dividing potential drop tap changer and no-load dividing potential drop by-pass cock.
Compared with prior art, the present invention has following beneficial effect:
(1) device simple structure of the present invention, traditional passive reactance device pick-up unit needs configuration current limiting reactor and short-circuit reactance device separately, and every class reactor all needs to configure a plurality of reactors and carries out permutation and combination.Each reactor of device of the present invention can use as current limiting reactor and short-circuit reactance device, has reduced the quantity of reactor, has therefore reduced cost, volume and the maintenance of device.
(2) device of the present invention is easy to operate, in the pick-up unit of traditional passive reactance device form, changes impedance complex steps, is unfavorable for that the voltage of realizing fast variform and amplitude falls.The gear switch that can utilize transformer dividing potential drop by-pass cock of apparatus of the present invention realizes falling of multiple amplitude fast, has reduced the time and the workload that detect
(3) device on-load of the present invention switches, and in the pick-up unit of traditional passive reactance device, when switching is fallen amplitude or fallen type, needs tested inverter to shut down the rear power supply that cuts off major loop and just can operate.Apparatus of the present invention have been utilized the feature that has the on-load switching of carrying partial pressure switch, switch while falling amplitude and gear and shut down without tested inverter, have increased substantially detection efficiency, if use no-load dividing potential drop by-pass cock, cannot switch by on-load.
(4) installation cost of the present invention is cheap, and traditional passive reactance device pick-up unit is used Thyristors in series valve or primary cut-out to realize the switching of falling amplitude and falling type.The cost of isolating switch and electronic power switch is higher.Apparatus of the present invention adopt the mode of transformer dividing potential drop by-pass cock gear switch to realize, and cost only has the former 10%, has greatly reduced the production cost of pick-up unit.
Accompanying drawing explanation
Fig. 1 is GB low voltage ride-through capability requirement schematic diagram;
Fig. 2 is low voltage crossing pick-up unit schematic diagram;
Fig. 3 is that reactor number is the low voltage crossing pick-up unit connection layout of 3 grid-connected photovoltaic inverter;
Topology diagram when Fig. 4 is a gear of transformer dividing potential drop by-pass cock WL1;
Topology diagram when Fig. 5 is two gear of transformer dividing potential drop by-pass cock WL1;
Fig. 6 is the low voltage crossing pick-up unit schematic diagram of grid-connected photovoltaic inverter;
Fig. 7 is transformer dividing potential drop by-pass cock WL6 structural drawing.
Embodiment
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail.
As shown in Figure 6, the low voltage crossing pick-up unit schematic diagram that Fig. 6 is grid-connected photovoltaic inverter; Low voltage crossing pick-up unit of the present invention comprises short circuit fling-cut switch, isolating switch C1, isolating switch C2, isolating switch C4 and minute voltage regulation module.Divide voltage regulation module to comprise that isolating switch C3, transformer dividing potential drop by-pass cock WL1, transformer dividing potential drop by-pass cock WL2, transformer dividing potential drop by-pass cock WL3, transformer dividing potential drop by-pass cock WL4, transformer dividing potential drop by-pass cock WL5 and N reactor L(N are more than or equal to 3).
Transformer one end connects electrical network, and the other end connects a minute voltage regulation module by isolating switch C1, and the neutral point of this transformer, short circuit fling-cut switch, isolating switch C4 and a minute voltage regulation module are connected successively; Divide voltage regulation module to be connected with photovoltaic DC-to-AC converter by isolating switch C2.Transformer neutral point is connected with the zero-span end of short circuit fling-cut switch WL6, and isolating switch C4 one end is connected with arbitrary gear of short circuit fling-cut switch WL6, and the isolating switch C4 other end is connected with transformer dividing potential drop by-pass cock WL5 zero-span end.
Transformer dividing potential drop by-pass cock WL2, N reactor L(N >=3 of minute voltage regulation module) and transformer dividing potential drop by-pass cock WL3 connect successively; N reactor L is multitap reactor, and transformer dividing potential drop by-pass cock WL2 controls with WL3 the reactor L being connected; The gear end of transformer dividing potential drop by-pass cock WL4 is connected respectively to the zero-span end of transformer dividing potential drop by-pass cock WL3 and reactor between any two, and the zero-span end of transformer dividing potential drop by-pass cock WL4 is connected respectively the zero-span end of photovoltaic DC-to-AC converter and transformer dividing potential drop by-pass cock WL1 by isolating switch C2 and isolating switch C3; Isolating switch C4 is connected with the zero-span end of transformer dividing potential drop by-pass cock WL5 with transformer dividing potential drop by-pass cock WL1 respectively with isolating switch C1; A gear of transformer dividing potential drop by-pass cock WL1 and transformer dividing potential drop by-pass cock WL5 and two gear cross connections; The zero-span end of transformer dividing potential drop by-pass cock WL2 and transformer dividing potential drop by-pass cock WL3 is connected respectively a gear end and the two gear ends of described transformer dividing potential drop by-pass cock WL1.
Isolating switch C1, C2, C3 and C4 are AC circuit breaker, and isolating switch C3 is bypass breaker, and isolating switch C4 is short interruption device.Each reactor all has 3, is respectively used to control three-phase electricity, and reactor parameter is between phase and phase equivalent.Transformer dividing potential drop by-pass cock WL1 and transformer dividing potential drop by-pass cock WL5 are the by-pass cock of two gears, transformer dividing potential drop by-pass cock WL1 and transformer dividing potential drop by-pass cock WL5 are coaxial switch, two transformer dividing potential drop by-pass cockes are synthesized together, the identical gear of while switching, two whiles all drop into 1 grade or two and all drop into 2 grades.
The gear number of transformer dividing potential drop by-pass cock WL2 and WL3 is corresponding with the tap number of reactor; The gear number of transformer dividing potential drop by-pass cock WL4 equates with reactor number; Short circuit fling-cut switch WL6 is the transformer dividing potential drop by-pass cock of ten gears.
Transformer dividing potential drop by-pass cock includes and carries dividing potential drop by-pass cock and no-load dividing potential drop by-pass cock.In test process, unified use has dividing potential drop by-pass cock or the no-load dividing potential drop by-pass cock of carrying.
As shown in Figure 3, the low voltage crossing pick-up unit connection layout that Fig. 3 is grid-connected photovoltaic inverter; The reactor number of this device is 3, this device comprises isolating switch C1, C2, C4, short circuit fling-cut switch WL6 and minute voltage regulation module, and a minute voltage regulation module comprises transformer dividing potential drop by-pass cock (WL1, WL2, WL3, WL4 and WL5), reactor (L1, L2, L3) and isolating switch C3.
Transformer one end is by the zero-span end of isolating switch C1 connection transformer dividing potential drop by-pass cock WL1, and the other end accesses electrical network; The neutral point of transformer, short circuit fling-cut switch WL6, isolating switch C4 and transformer dividing potential drop by-pass cock WL5 are connected successively; The zero-span end of transformer dividing potential drop by-pass cock WL4 connects photovoltaic DC-to-AC converter by isolating switch C2.
Transformer dividing potential drop by-pass cock WL1 and WL5 are the by-pass cock of two gears, one gear and two gear cross connections, and transformer dividing potential drop by-pass cock WL2 and WL3 be two gear ends and a gear end of connection transformer dividing potential drop by-pass cock WL1 respectively.
Reactor L1, L2, L3 are the reactor of four taps, and transformer dividing potential drop by-pass cock WL2 and WL3 are the by-pass cock of fourth gear position, and transformer dividing potential drop by-pass cock WL2, WL3 control respectively reactor L1, L2.
Transformer dividing potential drop by-pass cock WL4 is the by-pass cock of three gears, the gear end of transformer dividing potential drop by-pass cock WL4 is connected respectively between reactor L1 and L2, between reactor L2 and L3, the zero-span of transformer dividing potential drop by-pass cock WL3, the zero-span of transformer dividing potential drop by-pass cock WL4 is connected respectively the zero-span end of photovoltaic DC-to-AC converter and transformer dividing potential drop by-pass cock WL1 by isolating switch C2 and isolating switch C3.
Isolating switch C1, C2, C3 and C4 are AC circuit breaker, and isolating switch C3 is bypass breaker, and isolating switch C4 is short interruption device.
Transformer dividing potential drop by-pass cock is in the situation that not cutting off load current, completes the switch operating of load tap changer, under the load carrying prerequisite of transformer, has changed the no-load voltage ratio of transformer, thereby has changed the output voltage of transformer.Transformer dividing potential drop by-pass cock generally adopts in oil and to switch or mode that air switches, adopts resistor transition structure.Switch adopts electric rotating machine to complete switching and the integrated direct voltage regulating mode of operation, and simple in structure, installation and maintenance are convenient.
When the feature of transformer dividing potential drop by-pass cock is switching, transformer is without out of service, the present invention utilizes the tap of feature switching transformer and the topological structure of major loop of this switch, realizing low voltage crossing pick-up unit switches while falling amplitude, tested photovoltaic DC-to-AC converter is without out of service, reduce detection time, improved detection efficiency.
As shown in Figure 4,5, shown in topology diagram while being respectively a gear, two gears of transformer dividing potential drop by-pass cock WL1, when isolating switch C4 is during in closure state, when transformer dividing potential drop by-pass cock WL1 is during in 1 gear, magnitude of voltage n1 > n2 > n3, wherein, n1 is the node voltage value between reactor L1 and L2, n2 is the node reactance value between reactor L2 and L3, and n3 is the node voltage value of transformer dividing potential drop by-pass cock WL3 zero-span.
When transformer dividing potential drop by-pass cock WL1 is during in 2 gear, magnitude of voltage n1 ' < n2 ' < n3 ', wherein, n1 ' is the node voltage value between reactor L1 and L2, n2 ' is the node reactance value between reactor L2 and L3, and n3 ' is the node voltage value of transformer dividing potential drop by-pass cock WL3 zero-span.
As long as select suitable reactor parameter, just can meet magnitude of voltage n1 > n2 > n3 > n3 ' > n1 ' > n2 '.Transformer dividing potential drop by-pass cock WL4 act as the magnitude of voltage access photovoltaic DC-to-AC converter of above-mentioned node, realizes the line short fault simulation of different voltage magnitudes.
Transformer dividing potential drop by-pass cock WL2, WL3 are the by-pass cock of fourth gear position, are used for switching the reactor tap that drops into circuit.Reactor tap is more, and the gear of needed on-load voltage regulating switch is just more, falls a little just manyly, more easily realizes distribution uniformly in voltage range.
Transformer dividing potential drop by-pass cock WL6 is used for the earthing mode of change detection device as short circuit fling-cut switch, totally 10 kinds of the failure modes of general electrical network, and as shown in Figure 7, Fig. 7 is transformer dividing potential drop by-pass cock WL6 structural drawing.
As shown in following table 1 line fault type list, can select the transformer dividing potential drop by-pass cock of 10 gears to realize.
Table 1 line fault type list
The resistance value of tetra-taps of reactor L1 is respectively Z11, Z12, Z13, Z13, the resistance value of four taps of reactor L3 is respectively Z31, Z32, Z33, Z34, the resistance value of reactor L2 is Z2, pick-up unit can produce fall amplitude with as shown in table 2 below without the relation of field switch:
The amplitude correspondence of falling that WL1, the WL2 of table 2 low voltage crossing pick-up unit, WL3, WL4 switch gear form is shown
Note: Z in table
xrepresent power-supply system equiva lent impedance;
This device has 18 kinds and falls amplitude as can be known from Table 2, if selected reactor tap to select suitable numerical value, just can guarantee, in situation that the total capacity of short circuit of pick-up unit is identical, to have the different amplitudes of falling.
Transformer dividing potential drop by-pass cock WL6 is used for the earthing mode of change detection device as short circuit fling-cut switch, but during analogue ground fault, earth point is generally connected to the neutral point of isolating transformer secondary side in figure.
To of the present invention, be elaborated, a kind of embodiment of the present invention is as follows in conjunction with the embodiments:
The inverter that photovoltaic DC-to-AC converter detects max cap. on market is 630kW, and testing laboratory's access electric pressure mostly is 10kV.Device of the present invention, according to the related request of domestic and international photovoltaic standard, is designed the low voltage crossing pick-up unit of following scheme:
Power supply is insert experiment chamber after the 110/10.5kV of transformer station step-down, and in order to prevent that the electrical network quality of power supply is exerted an influence, designing power supply accesses low voltage crossing pick-up unit after the isolation change of 4MVA.Under the prerequisite of known transforming plant main transformer and isolation variable element, first carry out following reduction:
(1) transforming plant main transformer reactance value
Transformer parameter: 110/10.5kV short-circuit impedance Uk=10.5% capacity 31.5MVA;
(2) isolation becomes reactance value:
Transformer parameter: 10/10kV d short-circuit impedance Uk=8%, capacity 4MVA
Total system reactance X
t=2.0+0.333=2.333
Consider the reactance factor of circuit, general system impedance is estimated in 2.5 left and right.
During reactor design, consider that total system reactance meets various voltage and falls requirement, fall and o'clock in 0%～90% scope, be uniformly distributed, so L1, L2 select the reactor of 5 taps.According to different requirements, select different reactor tap numbers.The parameter of 3 kinds of reactors is as follows:
Reactor L1:
5 tap reactors, inductance value is respectively 8mH, 16mH, 24mH, 32mH, 40mH
Reactor L2:
Independent reactor: 40mH
Reactor L3:
5 tap reactors, inductance value is respectively 72mH, 80mH, 88mH, 96mH, 104mH
Control by above three kinds of reactors through transformer dividing potential drop by-pass cock, the voltage that pick-up unit can produce falls amplitude and falls as shown in amplitude correspondence shows as following table 3 pick-up units:
Table 3 pick-up unit falls the corresponding table of amplitude
Note: increasing along with L1, L3 voltage tap in theory, can increase more voltage and fall amplitude point, but the error of voltage being fallen to amplitude due to national and foreign standards is controlled at ± and 5%, it is too intensive that to fall amplitude point itself nonsensical, the pick-up unit of the scheme manufacture of the present embodiment accomplished voltage fall amplitude without dead band.
Finally should be noted that: above embodiment is only for illustrating the application's technical scheme but not restriction to its protection domain; although the application is had been described in detail with reference to above-described embodiment; those of ordinary skill in the field are to be understood that: those skilled in the art still can carry out all changes, revise or be equal to replacement to the embodiment of application after reading the application; but these change, revise or be equal to replacement, within the claim protection domain all awaiting the reply in application.
Claims (9)
1. a low voltage crossing pick-up unit for grid-connected photovoltaic inverter, is characterized in that: described device comprises a minute voltage regulation module, isolating switch C1, isolating switch C2, isolating switch C4 and short circuit fling-cut switch;
Transformer two ends connect with electrical network respectively and are connected with described minute voltage regulation module by described isolating switch C1; The neutral point of described transformer, described short circuit fling-cut switch, described isolating switch C4 and described minute voltage regulation module are connected successively; Within described minute, voltage regulation module is connected with photovoltaic DC-to-AC converter by described isolating switch C2.
2. the low voltage crossing pick-up unit of a kind of grid-connected photovoltaic inverter as claimed in claim 1, is characterized in that: described minute voltage regulation module comprises transformer dividing potential drop by-pass cock WL2, N reactor L(N >=3 of series connection successively) and transformer dividing potential drop by-pass cock WL3; Described reactor is multitap reactor, and described transformer dividing potential drop by-pass cock WL2 controls respectively with WL3 the described reactor L being connected;
The gear end of transformer dividing potential drop by-pass cock WL4 is connected to the zero-span end of described transformer dividing potential drop by-pass cock WL3 and reactor between any two, the zero-span end of described transformer dividing potential drop by-pass cock WL4 by isolating switch C2 and isolating switch C3 respectively be connected described photovoltaic DC-to-AC converter and be connected with the zero-span end of transformer dividing potential drop by-pass cock WL1;
Described isolating switch C4 is connected with the zero-span end of transformer dividing potential drop by-pass cock WL5 with transformer dividing potential drop by-pass cock WL1 respectively with described isolating switch C1;
A gear of described transformer dividing potential drop by-pass cock WL1 and described transformer dividing potential drop by-pass cock WL5 and two gear cross connections; The zero-span end of described transformer dividing potential drop by-pass cock WL2 and transformer dividing potential drop by-pass cock WL3 is connected with two gear ends with a gear end of described transformer dividing potential drop by-pass cock WL1 respectively.
3. the low voltage crossing pick-up unit of a kind of grid-connected photovoltaic inverter as claimed in claim 2, it is characterized in that: the zero-span of described transformer dividing potential drop by-pass cock WL1 and WL5 is connected respectively described isolating switch C1 and described isolating switch C4 a gear of described transformer dividing potential drop by-pass cock WL1 and WL5 and two gear cross connections.
4. the low voltage crossing pick-up unit of a kind of grid-connected photovoltaic inverter as claimed in claim 2, it is characterized in that: described transformer dividing potential drop by-pass cock WL1 and described transformer dividing potential drop by-pass cock WL5 are the by-pass cock of two gears, described transformer dividing potential drop by-pass cock WL1 is the switch of the identical gear of while switching with described transformer dividing potential drop by-pass cock WL5;
The gear number of described transformer dividing potential drop by-pass cock WL2 and WL3 is corresponding with the tap number of reactor;
The gear number of described transformer dividing potential drop by-pass cock WL4 equates with reactor number;
The transformer dividing potential drop by-pass cock that described short circuit fling-cut switch is ten gears.
5. the low voltage crossing pick-up unit of a kind of grid-connected photovoltaic inverter as claimed in claim 1, is characterized in that: described isolating switch C1, described isolating switch C2 and described isolating switch C4 are AC circuit breaker; Described isolating switch C4 is short interruption device.
6. the low voltage crossing pick-up unit of a kind of grid-connected photovoltaic inverter as claimed in claim 2, is characterized in that: described isolating switch C3 is AC circuit breaker; Described isolating switch C3 is bypass breaker.
7. the low voltage crossing pick-up unit of a kind of grid-connected photovoltaic inverter as claimed in claim 2, it is characterized in that: described reactor is the node voltage access photovoltaic DC-to-AC converter of the zero-span end of node voltage and described transformer dividing potential drop by-pass cock WL4 between any two, realizes the line short fault simulation of different voltage magnitudes.
8. the low voltage crossing pick-up unit of a kind of grid-connected photovoltaic inverter as claimed in claim 2, is characterized in that: described transformer dividing potential drop by-pass cock WL2 and described transformer dividing potential drop by-pass cock WL3 are for switching the reactor tap that drops into circuit;
Described reactor tap is more, and the gear of the transformer dividing potential drop by-pass cock needing is just more, falls a little just manyly, and the distribution in voltage range is more even.
9. the low voltage crossing pick-up unit of a kind of grid-connected photovoltaic inverter as described in claim 1-7 arbitrary, is characterized in that: described transformer dividing potential drop by-pass cock includes and carries dividing potential drop tap changer and a no-load dividing potential drop by-pass cock.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310524546.2A CN103529335B (en) | 2013-10-30 | 2013-10-30 | A kind of low voltage crossing detection device of grid-connected photovoltaic inverter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310524546.2A CN103529335B (en) | 2013-10-30 | 2013-10-30 | A kind of low voltage crossing detection device of grid-connected photovoltaic inverter |
Publications (2)
| Publication Number | Publication Date |
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| CN103529335A true CN103529335A (en) | 2014-01-22 |
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| CN103941050A (en) * | 2014-03-13 | 2014-07-23 | 北京群菱能源科技有限公司 | Reactor switching system of voltage dropping device |
| CN104316835A (en) * | 2014-10-27 | 2015-01-28 | 国家电网公司 | Low-voltage ride-through detection device used for small grid-connection photovoltaic inverter |
| CN107272645A (en) * | 2017-06-28 | 2017-10-20 | 中国能源建设集团甘肃省电力设计院有限公司 | The photovoltaic electric station grid connection fault model and analysis method of Neutral Grounding through Resistance in Electrical |
| CN108344943A (en) * | 2018-01-10 | 2018-07-31 | 云南电网有限责任公司电力科学研究院 | A kind of DFIG low voltage ride-through testing methods and device |
| CN108375730A (en) * | 2018-02-07 | 2018-08-07 | 上海交通大学 | Low-voltage ride-through testing system based on converter structure and method |
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| CN108344943A (en) * | 2018-01-10 | 2018-07-31 | 云南电网有限责任公司电力科学研究院 | A kind of DFIG low voltage ride-through testing methods and device |
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| CN108375730B (en) * | 2018-02-07 | 2020-02-18 | 上海交通大学 | Low voltage ride through test system and method based on converter structure |
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