CN210536537U - On-load voltage regulation circuit with polarity conversion for staggered parallel multi-gear transformer - Google Patents

Abstract

The utility model relates to the field of distribution transformers, in particular to an on-load voltage regulation circuit of a staggered parallel multi-gear transformer with polarity conversion, which comprises a main winding, a polarity conversion switch, a voltage regulation winding, a transition switching unit, a rated voltage branch and a plurality of voltage regulation branches; according to the technical scheme, a polarity change-over switch is arranged between a main winding and a voltage regulating winding, and positive and negative voltage regulation is realized by adjusting an independent contact switch-on end of the polarity change-over switch; one end of each voltage regulating branch is respectively connected to two end taps of the voltage regulating winding and each middle tap; and the other ends of the two groups of the three-phase alternating current transformer are adjacently connected in parallel in a staggered mode to form two groups and respectively connected with two input ends of the transition switching unit, the input end of the rated voltage branch is connected with the output end of the main winding, and the output end of the rated voltage branch is connected with the output end of the voltage regulating circuit. The beneficial effects of the utility model are that reduce on-off switch's break-make frequency, increase corresponding regulating switch's life and need not to jump the shelves pressure regulating.

Description

On-load voltage regulation circuit with polarity conversion for staggered parallel multi-gear transformer

Technical Field

The utility model relates to a distribution transformer field particularly relates to a transformer on-load voltage regulation circuit.

Background

Under application number 201610121960, entitled: the patent of 'a permanent magnet vacuum on-load tap changer, a transformer and an on-load tap changing method' provides an on-load tap changing method which applies two vacuum arc extinguishing chambers to respectively form a main loop and a transition loop structure. The technical scheme is as follows: when the circuit normally operates, the main loop vacuum arc-extinguishing chamber is switched on, the main loop is in a switching-on state, the transition loop vacuum arc-extinguishing chamber is switched off, the transition loop is in a switching-off state, and the voltage regulating winding connected into the main loop determines the external voltage supply gear of the circuit. When the gears are switched, the transition loop vacuum arc-extinguishing chamber is closed firstly, the transition loop is in a connected state, then the main loop vacuum arc-extinguishing chamber is disconnected, and the main loop is in a disconnected state. At this time, the gearshift switch completes the gearshift without current, and no arc is generated. The transition loop provides transition voltage for the circuit when the gear is switched, and the circuit is ensured not to interrupt the external voltage supply. However, the multi-step voltage regulating circuit designed according to the method has the following defects:

1. the main loop vacuum arc-extinguishing chamber is opened and closed once and the transition loop vacuum arc-extinguishing chamber is also closed and opened once when the gears are switched once every time. The main loop and the transition loop vacuum arc-extinguishing chamber are used as the devices with the highest on-off frequency in the circuit, and the upper limit of the on-off times of the main loop and the transition loop vacuum arc-extinguishing chamber determines the service life of the voltage regulating switch designed according to the circuit. According to the standard requirement, the mechanical life of the on-load voltage regulating switch reaches 50 ten thousand times, namely, the voltage regulating switch carries out 50 ten thousand times of tapping conversion operation under the condition that the contact is not electrified and the whole tapping range is used. According to the voltage regulating circuit, the on-load voltage regulating switches with 5 gears perform one voltage regulating cycle, and the main loop and the transition loop act for 4 x 50=200 ten thousand times. For the on-load tap changer with 9 gears, the main loop and the transition loop are required to act 8 x 50=400 ten thousand times. The mechanical service life of the vacuum arc-extinguishing chamber is required to be 80-120 ten thousand times at the present stage. Therefore, the mechanical life of the voltage regulating switch produced according to the voltage regulating circuit is a severe test, and the deduction is not up to the mechanical life required by the standard.

2. The transition loop is fixedly connected to a tap, and the pressure regulation of any gear needs to return to the fixed tap first and then to the gear needing pressure regulation, commonly called gear skipping pressure regulation. The transient change of the voltage can generate an operation overvoltage with very high amplitude, and the higher the transient change rate of the voltage is, the higher the amplitude of the generated overvoltage is, so that the damage to electronic products in a power grid is great. The standard is not to allow for trip voltage regulation.

The application numbers are: 201721680735.9, the name is: in the patent of "a method for voltage regulation on load using a double throw switch", an improvement is made to the patent 201610121960: the structure of the tapping coil is simpler; the transition loop is connected to the rated gear instead of the main winding end of the transformer, so that the voltage fluctuation is small when the gear is shifted. There are several variations of this patent. But the two fundamental points are the same as patent 201610121960: 1. when the gear is switched once, the vacuum arc extinguish chamber of the main loop needs to be opened and closed once, and the transition loop needs to be opened and closed once. The upper limit of the on-off times of the voltage regulating switch determines the service life of the voltage regulating switch designed according to the circuit. 2. The transition circuit is fixedly connected with a tap of the main winding, and the trip voltage regulation is still performed during voltage regulation, which is not allowed by the standard.

In patent 201820286271.1, patent 201721680735.9 is modified to add a transitional loop selector switch (the number of the transitional loop selector switches is changed according to the different voltage regulating gears, and 2 transitional loop selector switches are needed in 5 gears). The transition loop is not fixedly connected to the main connection gear of the voltage regulating winding, but changes along with the change of the gear through the transition loop selection switch. However, each time the gear is switched, the vacuum arc-extinguishing chamber of the main loop needs to be opened and closed once, and the transition loop needs to be opened and closed once. The defect that the service life of the voltage regulating switch designed according to the circuit is determined by the upper limit of the on-off times of the voltage regulating switch is still not changed. And with the increase of the number of switch gears, the number of selection switches of the transition circuit also increases, and the switch structure tends to be complex.

SUMMERY OF THE UTILITY MODEL

The utility model aims at: a new circuit structure is designed to replace the design of a transition loop and a main loop, and the on-off frequency of a vacuum arc extinguish chamber in the circuit in the voltage regulating process is reduced, so that the purpose of prolonging the service life of a corresponding voltage regulating switch is achieved; in the voltage regulating process, transition voltage is different along with different transition switching gears, voltage fluctuation during voltage regulation is reduced, and the problem of gear skipping voltage regulation is avoided; meanwhile, the forward and reverse voltage regulation functions are added into the on-load voltage regulation circuit, so that the purposes of reducing the number of voltage regulation windings, simplifying the structure of the transformer and reducing the manufacturing cost on the premise of the same gear number are achieved.

In order to realize the purpose of the utility model, the technical scheme of the utility model is that:

an on-load voltage regulation circuit of a staggered parallel multi-gear transformer with polarity conversion comprises a main winding, a polarity conversion switch, a voltage regulation winding, a transition switching unit, a rated voltage branch and a plurality of voltage regulation branches;

the voltage regulating winding is formed by sequentially connecting N sections of coils wound in the same direction end to end, the voltage regulating winding comprises two end taps and N-1 middle taps, the input end of the main winding is connected with the input end of the voltage regulating circuit, and the output end of the main winding is connected with a common contact of the polarity conversion switch; two independent contacts of the polarity conversion switch are respectively connected with two end taps of the voltage regulating winding;

the transition switching unit comprises two input ends and an output end, and the output end of the transition switching unit is used as the output end of the voltage regulating circuit; the first input end of the transition switching unit and the output end of the transition switching unit are connected in series with an on-off switch and a transition resistor which are connected in parallel, and the second input end of the transition switching unit is connected with the output end of the transition switching unit (the output end of the transition switching unit is also the output end of the voltage regulating circuit).

Preferably, the transition switching unit is formed by connecting a transition resistor and an on-off switch in parallel, a first input end of the transition switching unit is connected with a first end of the transition resistor and a first end of the on-off switch, a second input end of the transition switching unit is also used as an output end of the transition switching unit, and an output end of the transition switching unit is connected with a second end of the transition resistor and a second end of the on-off switch.

Preferably, the on-off switch in the transition switching unit is a vacuum arc-extinguishing chamber, and the electric arc does not pollute the transformer oil.

Each voltage regulating branch is connected with an on-off switch in series, and one end of each voltage regulating branch is respectively connected to two end taps of the voltage regulating winding and each middle tap; and the other ends of the voltage regulating branches are adjacently connected in parallel in a staggered manner to form two groups, and are respectively connected with the two input ends of the transition switching unit. Preferably, the on-off switch adopts a vacuum arc-extinguishing chamber, and electric arcs cannot pollute transformer oil.

The rated voltage branch is connected with an on-off switch in series, and one end of the rated voltage branch is connected with the output end of the main winding; the other end may be connected to either end of the transitional switching unit. Preferably, the rated voltage branch is connected to the first input end of the transition switching unit, and the output current does not pass through a switch in the transition switching unit during rated gear; the on-off switch preferably uses a vacuum arc-extinguishing chamber, and electric arcs cannot pollute transformer oil.

Specifically, each voltage regulating coil of the voltage regulating winding is connected end to end, and the number of the voltage regulating coils in the voltage regulating winding is determined according to the gear of a voltage regulating circuit to be designed. The five-gear voltage regulating circuit is characterized in that a voltage regulating winding consists of two voltage regulating coils; and the seven-gear voltage regulating circuit and the voltage regulating winding consist of three voltage regulating coils. The voltage regulating winding can be connected in series with the head end, the middle part or the tail end of the main winding of the transformer to form end part, middle part or neutral point voltage regulation.

Two ends of each voltage regulating coil are respectively provided with a voltage regulating winding tap, wherein adjacent voltage regulating coil ends share one tap, and the number of the voltage regulating coils forming the voltage regulating winding plus one is the number of the voltage regulating winding taps. Tap numbers of the voltage regulating coils are sequentially defined from one end of the whole voltage regulating winding to the other end to be 1, 2 to n. The tap number 1 and the tap number n are the taps of the two end parts of the voltage regulating winding.

The number of the voltage regulating branches is consistent with that of the voltage regulating winding taps, and one end of each voltage regulating branch is connected with one corresponding voltage regulating winding tap.

And defining the voltage regulating branch connected with the tap No. 1 as the branch No. 1, defining the voltage regulating branch connected with the tap No. 2 as the branch No. 2, and analogizing until the branch No. n.

The other end of each voltage regulating branch has two kinds of connected modes:

the first connection mode is as follows: the other ends of all odd-numbered voltage regulating branches are connected with the second input end of the transition switching unit; and the other ends of all the even-numbered voltage regulating branches are connected with the first input end of the transition switching unit.

And a second connection mode: the other ends of all the even-numbered voltage regulating branches are connected with the second input end of the transition switching unit; the other ends of all odd-numbered voltage regulating branches are connected with the first input end of the transition switching unit.

Because the second input of transition switching unit is connected with whole voltage regulating circuit's output, so the voltage regulating branch road of the second input of defining to connect transition switching unit is the straight voltage regulating branch road that links, because it has a parallelly connected resistance and vacuum interrupter structure to establish ties between the first input of transition switching unit and the output of voltage regulating circuit, so the voltage regulating branch road of the first input of defining to connect transition switching unit is the non-straight voltage regulating branch road.

In the first connection mode, odd-numbered voltage regulating branches are direct-connected voltage regulating branches; the voltage regulating branches with even numbers are non-direct-connection voltage regulating branches.

In the second connection mode, odd-numbered voltage regulating branches are non-direct-connection voltage regulating branches; the voltage regulating branches with even numbers are direct-connected voltage regulating branches.

The polarity conversion switch is in an upper end connection state, the polarity of a voltage regulating winding of the access circuit is the same as that of the main winding, and the circuit can perform positive voltage regulation; the polarity conversion switch is in a lower end connection state, the polarity of a voltage regulating winding of the access circuit is opposite to that of the main winding, and the circuit can perform reverse voltage regulation.

In the positive voltage regulation process or the negative voltage regulation process, the voltage regulation winding of the access circuit can be regulated by independently closing the on-off switch of any voltage regulation branch circuit, and the on-off switch corresponds to different gears.

The on-off switch of any non-direct-connected voltage regulating branch is in a closed state, and meanwhile, the on-off switch of the transition switching unit is also in an on state, so that the voltage regulating circuit is in a normal operation state of a corresponding gear at the moment, and the state is defined as a normal working state of the non-direct-connected circuit.

The on-off switch of the direct connection voltage regulation branch circuit is in a closed state, the on-off switch of the transition switching unit is in an off state, the voltage regulation circuit is in a normal operation state of a corresponding gear at the moment, and the state is defined as a normal working state of the direct connection circuit.

From circuit structure, the technical scheme of the utility model, a pressure regulating branch road is for directly linking the pressure regulating branch road, and adjacent pressure regulating branch road must be for the non-directly links pressure regulating branch road with it. In the multi-gear transformer voltage regulating circuit under the scheme, all voltage regulating branches are necessarily connected in the alternative form.

The voltage regulating circuit under the technical scheme is switched from the normal working state of one voltage regulating branch circuit to the normal working state of the other voltage regulating branch circuit adjacent to the voltage regulating branch circuit in a gear switching mode. Or the normal working state of the direct connection voltage regulating branch circuit is switched to the normal working state of the non-direct connection voltage regulating branch circuit, or the normal working state of the non-direct connection voltage regulating branch circuit is switched to the normal working state of the direct connection voltage regulating branch circuit.

From the circuit structure, as long as the on-off switch of the transition switching unit is in an off state, the transition resistor is always connected in series between the two adjacent voltage regulating branches, so that the circuit is prevented from being short-circuited when the two adjacent voltage regulating branches are simultaneously in an on state, the two voltage regulating branches are allowed to be simultaneously in an on state, and the power supply is prevented from being interrupted in the voltage regulating process.

Therefore, as long as the on-off switch in the transition switching unit is in an off state, the voltage regulation can be started.

If from directly connecting the normal operating condition of pressure regulating branch road and switching to the normal operating condition of non-directly connecting pressure regulating branch road, because directly connecting the pressure regulating branch road and being in normal operating condition, the on-off switch of transition switching unit has been in the off-state this moment, so as long as the closure corresponds non-directly connecting pressure regulating branch road on-off switch, then the disconnection corresponds directly to connect pressure regulating branch road on-off switch, then switch on transition switching unit on-off switch, so then accomplish a gear and switch over.

If the normal working state of the non-direct-connection voltage-regulating branch is switched to the normal working state of the direct-connection voltage-regulating branch from the normal working state of the non-direct-connection voltage-regulating branch, the transition switching unit on-off switch is in the on state because the non-direct-connection branch is in the normal working state, the transition switching unit on-off switch is switched off firstly, then the corresponding direct-connection voltage-regulating branch on-off switch is closed, and then the corresponding non-direct-connection branch on-off switch.

Therefore the technical scheme of the utility model, it is not only on connected mode, as long as each pressure regulating branch road satisfies directly link with the mode of non-direct link alternate connection, can realize the same technological effect. The two connection modes can be regarded as two preferable embodiments under the same utility model.

Therefore use the utility model discloses a transformer, the gear is once switched, and the break-make switch in the transition switching unit only experiences once opening or once closes. The gear is switched twice continuously, and the on-off switch in the transition switching unit is switched on and off once. In the prior art, each time the gears are switched, the vacuum arc-extinguishing chambers of the main loop transition loop are opened and closed once respectively.

Compared with the prior art, the technical scheme can reduce half of the on-off times of the on-off switch on the premise of the same voltage regulation times. On the other hand, the utility model discloses technical scheme can let the pressure regulating branch road of previous gear provide the transition voltage for the pressure regulating branch road of adjacent gear, so the transition voltage can be along with the difference of pressure regulating gear always, and change thereupon.

Besides the positive voltage regulation and the negative voltage regulation, the switch from the positive voltage regulation to the negative voltage regulation or the switch from the negative voltage regulation to the positive voltage regulation is also provided. In the switching process, the polarity conversion switch needs to be switched from upper end connection to lower end connection or from lower end connection to upper end connection, and in the switching process, each voltage regulating branch is necessarily in an off state, so that transition voltage cannot be provided for the voltage regulating circuit.

The rated voltage branch bypasses the polarity change-over switch and is directly connected between the main winding tap and the output end of the voltage regulating circuit, the on-off switch of the rated voltage branch is closed, and the rated voltage branch is in a switch-on state, so that the circuit can be ensured not to interrupt voltage supply when positive and negative voltage regulation is switched.

Preferably, the on-off switch of the transition switching unit adopts a vacuum arc-extinguishing chamber, so that electric arcs cannot pollute transformer oil;

preferably, the on-off switches respectively connected in series with the voltage regulating branch and the rated voltage branch adopt vacuum arc-extinguishing chambers, and electric arcs cannot pollute transformer oil.

Alternatively, a first vacuum arc-extinguishing chamber is connected in series with a line from the second input end to the output end in the transition switching unit, a second vacuum arc-extinguishing chamber is connected in series with a line from the first input end to the output end through a transition resistor, and meanwhile, the on-off switches respectively connected in series with the voltage regulating branch and the rated voltage branch are both common on-off switches.

Further, as an option, the on-load voltage regulation circuit of the interleaved parallel multi-gear transformer with polarity conversion comprises a main winding, a polarity conversion switch, a voltage regulation winding, a transition switching unit, a rated voltage branch and three voltage regulation branches; the voltage regulating winding is formed by sequentially connecting two sections of voltage regulating coils wound in the same direction end to end, the voltage regulating winding comprises three taps including an upper tap, a middle tap and a lower tap, the input end of the main winding is connected with the input end of the voltage regulating circuit, and the output end of the main winding is connected with a common contact of the polarity change-over switch; two independent contacts of the polarity conversion switch are respectively connected with an upper end tap and a lower end tap of the voltage regulating winding;

the transition switching unit comprises two input ends and an output end, a transition resistor and a transition unit vacuum arc extinguish chamber which are connected in parallel with each other are connected in series between the first input end of the transition switching unit and the output end of the transition switching unit, the second input end of the transition switching unit is directly connected with the output end of the transition switching unit, the second input end of the transition unit is the output end of the transition switching unit and the output end of the voltage regulating circuit, and the three input ends are integrated.

The three voltage regulating branches and the rated voltage branch are respectively connected with a vacuum arc extinguish chamber in series and a voltage regulating branch connected with an upper end tap, and the other end of the voltage regulating branch is connected with a first input end of the transition switching unit; the other end of the voltage regulating branch is connected with a second input end of the transition switching unit; and the other end of the voltage regulating branch is connected with a first input end of the transition switching unit.

And the input end of the rated voltage branch is connected with the output end of the main winding, and the output end of the rated voltage branch is connected with the output end of the voltage regulating circuit.

As another option, the on-load voltage regulating circuit with the polarity-switching interleaved parallel multi-gear transformer comprises a main winding, a polarity switching switch, a voltage regulating winding, a transition switching unit, a rated voltage branch and three voltage regulating branches; the voltage regulating winding is formed by sequentially connecting two sections of voltage regulating coils wound in the same direction end to end, the voltage regulating winding comprises three taps including an upper tap, a middle tap and a lower tap, the input end of the main winding is connected with the input end of the voltage regulating circuit, and the output end of the main winding is connected with a common contact of the polarity change-over switch; two independent contacts of the polarity conversion switch are respectively connected with an upper end tap and a lower end tap of the voltage regulating winding;

the transition switching unit comprises two input ends and an output end, a transition resistor and a transition unit vacuum arc extinguish chamber which are connected in parallel with each other are connected in series between the first input end of the transition switching unit and the output end of the transition switching unit, the second input end of the transition switching unit is directly connected with the output end of the transition switching unit, the second input end of the transition unit is the output end of the transition switching unit and the output end of the voltage regulating circuit, and the three input ends are integrated.

The three voltage regulating branches and the rated voltage branch are respectively connected with a vacuum arc extinguish chamber in series and a voltage regulating branch connected with an upper end tap, and the other end of the voltage regulating branch is connected with a second input end of the transition switching unit; the voltage regulating branch is connected with the middle-end tap, and the other end of the voltage regulating branch is connected with a first input end of the transition switching unit; the other end of the voltage regulating branch is connected with a second input end of the transition switching unit;

the input end of the rated voltage branch is connected with the output end of the main winding, and the output end of the rated voltage branch is connected with the output end of the voltage regulating circuit.

To sum up, the foundation the utility model discloses the transformer that technical scheme designed has that voltage fluctuation is little, the output voltage high quality is halved with gear voltage regulation winding figure when long service life, vary voltage, low in manufacturing cost's advantage.

In the present invention, the input terminal and the output terminal are defined for clearly expressing the connection relationship of the constituent parts of the circuit, wherein "input" and "output" are used only for distinguishing different connection terminals, and do not represent the flowing or transmitting direction of the current or signal.

Drawings

Fig. 1 is a schematic diagram of a five-gear on-load positive-negative voltage regulation circuit applying the technical scheme of the utility model;

fig. 2 is a schematic diagram of a five-gear loaded positive-negative voltage regulation circuit in another connection mode according to the technical scheme of the present invention.

Detailed Description

The structural features and the working principle of the positive and negative voltage regulation circuit of the present invention will be further explained with reference to the accompanying drawings.

Referring to fig. 1, a schematic diagram of a voltage regulating circuit of a five-gear transformer in the technical scheme of the aspect is shown, and the circuit is composed of a main winding, a voltage regulating winding, a rated voltage branch, a transition switching unit and three voltage regulating branches.

The transition switching unit comprises a first input terminal T1, a second input terminal T2, an output terminal Xb and a parallel structure of a vacuum arc extinguish chamber D0 and a transition resistor R which are connected between the first input terminal T1 and the output terminal Xb in series.

First voltage regulating coil L1, second voltage regulating coil L2 end to end constitute voltage regulating winding, and voltage regulating coil both ends respectively are equipped with a voltage regulating winding tap, and wherein adjacent voltage regulating coil end shares a voltage regulating winding tap, and two voltage regulating coils are equipped with three voltage regulating winding taps altogether and are upper end tap X1, middle-end tap X2, lower extreme tap X3 respectively.

And a common contact of the polarity change-over switch KaKb is connected with the output end Xa of the main winding, and two independent contacts of the polarity change-over switch are respectively connected with an upper end tap X1 and a lower end tap X3 of the voltage regulating winding.

The on-off switch D1, the on-off switch D2, the on-off switch D3, and the on-off switch Ke are all vacuum arc-extinguishing chambers.

And one end of the on-off switch D1 is connected with a tap X1 at the upper end of the voltage regulating winding, and the other end of the on-off switch D1 is connected with a second input end T2 of the transition switching unit and exists as a voltage regulating branch.

And one end of the on-off switch D2 is connected with an end tap X2 in the voltage regulating winding, the other end of the on-off switch is connected with a first input end T1 of the transition switching unit, and the on-off switch is connected with an output end Xb of the voltage regulating circuit through a parallel structure of a vacuum arc-extinguishing chamber D0 and a resistor R and exists as a voltage regulating branch.

And one end of the on-off switch D3 is connected with a tap X3 at the lower end of the voltage regulating winding, and the other end of the on-off switch D3 is connected with a second input end T2 of the transition switching unit and exists as a voltage regulating branch.

And the rated voltage branch is connected with an on-off switch Ke in series, one end of the rated voltage branch is connected with the output end Xa of the main winding, and the other end of the rated voltage branch is connected with the second input end T2 of the transition switching unit.

The combination state of the polarity conversion switch and each on-off switch corresponds to each gear of the voltage regulating circuit as follows:

1, gear 1: ka closes D3 closes D0 and disconnects the voltage regulating windings L1 and L2 to be positively connected into the circuit

2, gear: ka-close D2-close DO-close regulating winding L1 positive access circuit

3, gear 3: ka closes D1 closes D0 and disconnects the voltage regulating windings L1 and L2 and is not connected to the circuit

3, gear 3: kb closes D3 closes D0 and disconnects the voltage regulating windings L1 and L2, which are not connected to the circuit

4, gear 4: kb and D2 and D0 voltage regulating winding L2 reverse access circuit

5, gear: kb closes D1 closes D0 and disconnects voltage regulating windings L1 and L2 which are reversely connected into a circuit

The pressure regulating process is as follows:

in the first gear, the polarity switch Ka is in an on state, the on-off switch D3 is in a closed state, the transition switching unit vacuum interrupter D0 is in an off state, and the voltage regulating windings L1 and L2 are both connected to the circuit.

When the first gear is switched to the second gear, the on-off switch D2 is closed firstly, the first gear and the second gear are connected together, and the transition resistor R protects the circuit from short circuit. The on-off switch D1 is then opened and the first gear circuit is in an open state. Then the vacuum interrupter D0 is closed, and the circuit completes the switch from first gear to second gear.

When the second gear is switched to the third gear, the transition switching unit vacuum arc-extinguishing chamber D0 is opened, the on-off switch D3 is closed, the on-off switch D2 is opened, and the circuit completes the switching from the second gear to the third gear.

When the three-gear is switched to the four-gear, the switching from the positive voltage regulation to the negative voltage regulation is completed firstly, and the on-off switch Ke is closed firstly, so that the rated voltage branch is in an on state. Then the on-off switch D1 is turned off, and the polarity changeover switch KaKb is in the power-off state, in which state the polarity changeover switch is switched from Ka terminal on to Kb terminal on. Then the on-off switch D3 is closed, the on-off switch Ke. is opened to complete the switching of positive voltage regulation to negative voltage regulation, and the circuit is always in third gear during the switching.

When the three-gear is switched to the fourth gear, the on-off switch D2 is closed, the on-off switch D3 is opened, then the transition switching unit vacuum arc-extinguishing chamber D0 is closed, and the circuit completes the switching from the third gear to the fourth gear.

When the fourth gear is switched to the fifth gear, the vacuum arc extinguish chamber D0 of the transition switching unit is firstly opened, then the on-off switch D1 is closed, then the on-off switch D2 is opened, and the circuit completes the switching from the fourth gear to the fifth gear.

With the five grades of voltage regulating circuit of prior art design, need four voltage regulating windings, and use the utility model relates to a five grades of circuits only need 2 voltage regulating windings, have reduced half voltage regulating winding use amount, have reduced corresponding manufacturing cost. Meanwhile, the transition voltage of the designed circuit changes along with the voltage regulation gear in the voltage regulation process, the voltage fluctuation is small, and the problem of gear skipping voltage regulation cannot occur; in the prior art, the voltage regulation process from a first gear to a fifth gear is completed once, four gear switching processes are required, and the main loop and the rated voltage branch vacuum arc-extinguishing chamber are closed and opened for four times. And the technical scheme of the utility model, the highest vacuum interrupter of break-make frequency only need close twice and open twice in the circuit, has reduced half break-make number of times, has improved the effective use number of times of corresponding transformer greatly.

Therefore, the five-gear on-load positive and negative voltage regulation transformer designed by the voltage regulation method of the utility model has the advantages of low cost, long service life and high voltage quality.

Referring to fig. 2, a schematic diagram of another five-gear transformer voltage regulating circuit in the technical scheme of the aspect is shown, and the circuit is composed of a main winding, a voltage regulating winding, a rated voltage branch, a transition switching unit and three voltage regulating branches.

The transition switching unit comprises a first input end T1, a second input end T2, an output end Xb, a vacuum arc extinguish chamber D0 connected between the first input end T1 and the output end Xb in series and a transition resistor R in parallel.

First voltage regulating coil L1, second voltage regulating coil L2 end to end constitute voltage regulating winding, and voltage regulating coil both ends respectively are equipped with a voltage regulating winding tap, and wherein adjacent voltage regulating coil end is a voltage regulating winding tap altogether, and two voltage regulating coils are equipped with three voltage regulating winding taps altogether and are upper end tap X1, middle-end tap X2, lower extreme tap X3 respectively.

And a common contact of the polarity change-over switch KaKb is connected with the output end Xa of the main winding, and two independent contacts of the polarity change-over switch are respectively connected with an upper end tap X1 and a lower end tap X3 of the voltage regulating winding.

The on-off switch D1, the on-off switch D2, the on-off switch D3, and the on-off switch Ke are all vacuum arc-extinguishing chambers.

And one end of the on-off switch D1 is connected with a tap X1 at the upper end of the voltage regulating winding, the other end of the on-off switch is connected with a first input end T1 of the transition switching unit, and the on-off switch is connected with an output end Xb of the voltage regulating circuit through a parallel structure of a vacuum arc-extinguishing chamber D0 and a resistor R and exists as a voltage regulating branch.

And one end of the on-off switch D2 is connected with an end tap X2 in the voltage regulating winding, and the other end of the on-off switch D2 is connected with a second input end T2 of the transition switching unit and exists as a voltage regulating branch.

And one end of the on-off switch D3 is connected with a tap X3 at the lower end of the voltage regulating winding, the other end of the on-off switch is connected with a first input end T1 of the transition switching unit, and the on-off switch is connected with an output end Xb of the voltage regulating circuit through a parallel structure of a vacuum arc-extinguishing chamber D0 and a resistor R and exists as a voltage regulating branch.

And the rated voltage branch is connected with an on-off switch Ke in series, one end of the rated voltage branch is connected with the output end Xa of the main winding, and the other end of the rated voltage branch is connected with the second input end T2 of the transition switching unit.

The combination state of the polarity conversion switch and the on-off switches of the branches corresponds to the gears of the voltage regulating circuit as follows:

1, gear 1: ka-closed D3-closed D0-closed voltage regulating windings L1 and L2 are positively connected into a circuit

2, gear: ka closes D2 closes DO and opens the positive switch-in circuit of the voltage regulating winding L1

3, gear 3: ka closes D1 closes D0 and closes regulating winding L1, L2 and do not insert the circuit

3, gear 3: kb closes D3 closes D0 closes voltage regulating windings L1, L2 and do not connect the circuit

4, gear 4: kb closes D2 closes D0 and disconnects voltage regulating winding L2 to reversely access the circuit

5, gear: kb and D1 and D0 and voltage regulating windings L1 and L2 are reversely connected into a circuit

The pressure regulating process is as follows:

in the first gear, the polarity switch Ka is in an on state, the on-off switch D3 is in a closed state, the transition switching unit vacuum arc-extinguishing chamber D0 is in a closed state, and the voltage-regulating windings L1 and L2 are both connected to the circuit.

When the first gear is switched to the second gear, the vacuum arc extinguish chamber D0 of the transition switching unit is firstly opened, then the on-off switch D2 is closed, the first gear and the second gear are connected together, and the transition resistor R protects the circuit from short circuit. The on-off switch D3 is then opened and the first gear circuit is in an open state. Then the vacuum interrupter D0 is opened, and the circuit completes the switching from the first gear to the second gear.

When the second gear is switched to the third gear, the on-off switch D1 is closed, then the on-off switch D2 is opened, then the vacuum arc-extinguishing chamber D0 of the transition switching unit is closed, and the circuit completes the switching from the second gear to the third gear.

When the three-gear is switched to the four-gear, the switching from the positive voltage regulation to the negative voltage regulation is completed firstly, and the on-off switch Ke is closed firstly, so that the rated voltage branch is in an on state. Then, the on-off switch D1 is turned off, and the polarity changeover switch KaKb is in a power-off state in which the polarity changeover switch on terminal is switched. And switching the polarity conversion switch from the Ka end to the Kb end. Then the on-off switch D3 is closed, the on-off switch Ke. is opened to complete the switching of positive voltage regulation to negative voltage regulation, and the circuit is always in third gear during the switching.

When the three-gear is switched to the fourth gear, the vacuum arc extinguish chamber D of the transition switching unit is firstly opened, then the on-off switch D2 is closed, the on-off switch D3 is opened, and the circuit completes the switching from the third gear to the fourth gear.

When the four-gear is switched to the fifth gear, the on-off switch D1 is closed, then the on-off switch D2 is opened, then the transition switching unit vacuum arc-extinguishing chamber D0 is closed, and the circuit completes the switching from the fourth gear to the fifth gear.

Compared with the circuit in fig. 1, the circuit in fig. 2 has the same technical effect, although the connection mode is different. Compared with the prior art, the purpose of reducing half of the use amount of the voltage regulating winding and reducing the corresponding production cost is also realized; meanwhile, the transition voltage of the designed circuit changes along with the voltage regulation gear in the voltage regulation process, and the problem of gear skipping voltage regulation is avoided; the on-off frequency of the vacuum arc extinguish chamber in the circuit is low.

Claims (8)

1. An on-load voltage regulation circuit of a staggered parallel multi-gear transformer with polarity conversion comprises a main winding, a polarity conversion switch, a voltage regulation winding, a transition switching unit, a rated voltage branch and a plurality of voltage regulation branches;

the voltage regulating circuit is characterized in that the voltage regulating winding is formed by sequentially connecting N sections of coils wound in the same direction end to end, the voltage regulating winding comprises two end taps and N-1 middle taps, the input end of the main winding is connected with the input end of the voltage regulating circuit, and the output end of the main winding is connected with a common contact of the polarity conversion switch; two independent contacts of the polarity conversion switch are respectively connected with two end taps of the voltage regulating winding;

the transition switching unit comprises two input ends and an output end, and the output end of the transition switching unit is used as the output end of the voltage regulating circuit; a transition resistor and a transition switching unit on-off switch which are connected in parallel are connected in series between the first input end of the transition switching unit and the output end of the transition switching unit, and the second input end of the transition switching unit is connected with the output end of the transition switching unit;

one end of each voltage regulating branch is respectively connected to two end taps of the voltage regulating winding and each middle tap; the other ends of the voltage regulating branches are adjacently connected in parallel in a staggered mode to form two groups, and the two groups are respectively connected with the two input ends of the transition switching unit;

each voltage branch and the rated voltage branch are respectively connected with an on-off switch in series;

the rated voltage branch is connected with an on-off switch in series, and one end of the rated voltage branch is connected with the output end of the main winding; the other end may be connected to either end of the transitional switching unit.

2. The on-load tap changer of claim 1, wherein the transition switching unit comprises a transition resistor and an on-off switch connected in parallel, a first input terminal of the transition switching unit is connected to a first terminal of the transition resistor and a first terminal of the on-off switch, a second input terminal of the transition switching unit is also used as an output terminal of the transition switching unit, and an output terminal of the transition switching unit is connected to a second terminal of the transition resistor and a second terminal of the on-off switch.

3. The on-load tap changer of an interleaved parallel multi-step transformer with polarity switching according to claim 1, wherein: the on-off switch of the transition switching unit adopts a vacuum arc-extinguishing chamber.

4. The on-load tap changer of an interleaved parallel multi-step transformer with polarity switching according to claim 1, wherein: one end of the rated voltage branch circuit is connected with the output end of the main winding; the other end is connected with the output end of the transition switching unit.

5. An on-load tap changer for an interleaved parallel multi-step transformer with polarity reversal according to claim 1, characterized in that the on-off switches connected in series in the tap changing branch and the rated voltage branch can be vacuum interrupters.

6. The on-load tap changer of an interleaved parallel multi-step transformer with polarity switching according to claim 1, wherein: a first vacuum arc-extinguishing chamber is connected in series on a line from the second input end to the output end in the transition switching unit, a second vacuum arc-extinguishing chamber is connected in series on a line from the first input end to the output end through the transition resistor, and the on-off switches connected in series on the voltage regulating branch and the rated voltage branch are common on-off switches.

7. An on-load tap changing circuit for an interleaved parallel multi-step transformer with polarity inversion according to claim 2 or claim 3, wherein: the voltage regulating winding is formed by sequentially connecting two sections of voltage regulating coils wound in the same direction end to end, and comprises three taps including an upper tap, a middle tap and a lower tap; two independent contacts of the polarity conversion switch are respectively connected with an upper end tap and a lower end tap of the voltage regulating winding; the three voltage regulating branches and the rated voltage branch are respectively connected with a vacuum arc-extinguishing chamber in series;

the other end of the voltage regulating branch is connected with a first input end of the transition switching unit; the other end of the voltage regulating branch is connected with a second input end of the transition switching unit; the other end of the voltage regulating branch is connected with a first input end of the transition switching unit;

one end of the rated voltage branch circuit is connected with the output end of the main winding; the other end is connected with the output end of the transition switching unit.

8. An on-load tap changing circuit for an interleaved parallel multi-step transformer with polarity inversion according to claim 2 or claim 3, wherein: the voltage regulating winding is formed by sequentially connecting two sections of voltage regulating coils wound in the same direction end to end, and comprises three taps including an upper tap, a middle tap and a lower tap; two independent contacts of the polarity conversion switch are respectively connected with an upper end tap and a lower end tap of the voltage regulating winding; the three voltage regulating branches and the rated voltage branch are respectively connected with a vacuum arc-extinguishing chamber in series;

the other end of the voltage regulating branch is connected with a second input end of the transition switching unit; the voltage regulating branch is connected with the middle-end tap, and the other end of the voltage regulating branch is connected with a first input end of the transition switching unit; the other end of the voltage regulating branch is connected with a second input end of the transition switching unit;

one end of the rated voltage branch circuit is connected with the output end of the main winding; the other end is connected with the output end of the transition switching unit.

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