JPH061414B2 - Load tap switching device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load tap switching device in which a switching switch is composed of a thyristor circuit using a thyristor switch.

[Conventional technology]

As a conventional tap changer for load using a thyristor switch, there is one shown in Japanese Patent Laid-Open No. 47-16918. FIG. 8 shows the configuration, and FIG. 9 shows the configuration of the control circuit. In the figure, 1 is a selective contactor which is in contact with an arbitrary tap U ₁ of a transformer tap winding having a plurality of taps, 2 is a tap U ₂ which is adjacent to the tap U ₁ which is in contact with the selective contactor 1. Selective contactor 3 in contact is a main contactor connected in series between the selectable contactor 1 and the output terminal, and 4 is a main contact connected in series between the selective contactor 2 and the output terminal. In the child, one end of the main contacts (3) and (4) are commonly used as an output terminal y. (5) is a thyristor circuit (S) in which thyristor elements (7) and (8) are connected in antiparallel.
t ₁ ) is connected in series to the main contactor (3) in parallel, and (6) is connected in series to the thyristor circuit St _{2 in} which the thyristor elements 9 and 10 are connected in antiparallel. It is an auxiliary contactor connected in parallel to the main contactor 4.
When the tap U ₁ of this load tap changer is cut off and switched to the tap U ₂ , the auxiliary contacts 5 and 6 are first closed while the main contact 3 is closed. Next, the thyristor circuit St ₁ is closed and then the main contactor 3 is opened.
After a short delay, St ₁ is opened and at the same time the thyristor circuit St ₂ is closed and the main contact 4 is closed.
After that, St ₂ is “opened” and finally the auxiliary contact 5,
Open 6 Thyristor circuit S during the above-mentioned opening / closing operation
The thyristor elements 7, 8, 9, 10 of t ₁ and St ₂ are the ninth
It is controlled by the circuit shown. Reference numeral 11 is an ignition transformer for transmitting an ignition pulse train for controlling the firing of the thyristor circuit St ₁ , 12 is an ignition transformer for transmitting an ignition pulse train for controlling the firing of the thyristor circuit St ₂ , and 13 is a thyristor circuit St ₁ An ignition pulse generator for generating an ignition pulse train for controlling the opening and closing of the main contactor 20, an open / closed state of the main contactor 3, and a state alarm 21 for detecting the open / closed state of the main contactor 4, respectively.
Each has an output terminal 100 or 101. Two
Reference numeral 2 is an auxiliary contactor 5, 23 is a state alarm for detecting the open / closed state of the auxiliary contactor 6, and has output terminals 102 or 103 and 104 or 105, respectively. Reference numeral 24 is a thyristor St ₁ , 25 is a status alarm for detecting the presence or absence of a potential difference between the anode and cathode of the thyristor St ₂ , and has a respective output terminal 106 or 107. Reference numeral 15 is a storage element that stores the output states of the state annunciators 20 and 21. 26, 27, 30, 31, 38 and 39 are output terminals 110, 111, 112, 11 respectively.
An AND gate having 3,118 and 11. Three
Reference numerals 4 and 35 are OR gates having non-inverted signal terminals 114 and 116 and inverted signal terminals 115 and 117, respectively.

Next, the functions of the above components will be described. When the main contacts 3 and 4 are closed, the output of the output terminals 100 and 101 of the status alarms 20 and 21 becomes a logic level 1 (hereinafter, the output terminals 100 and 101 are represented as "1"),
When opened, the outputs of the output terminals 100 and 101 are configured to have a logic level 0 (hereinafter, the output terminals 100 and 101 are represented as "0"). Status alarm 2
When the auxiliary contacts 5 and 6 are closed, the output terminals 102 and 104 of the output terminals 2 and 23 are "1" and the output terminals 10 and 10, respectively.
When 3, 105 are "0" and in the open state, the output terminals 102 and 104 are "0" and the output terminals 103 and 105 are "1". Further, the status alarms 24 and 25 output terminals 106 and 107, respectively, when there is a potential difference between the anode and cathode of the thyristor circuits St ₁ and St _2.
Is set to "1", and when there is no potential difference, the output terminal 10
6,107 becomes "0". The storage element 15 stores the state when the output terminal 100 of the status annunciator 20 is "1", sets its output terminal 108 to "1", sets the output terminal 109 to "0", and outputs the output terminal of the status annunciator 21. 101 is "1"
At this time, the output terminal 108 is set to "0" and the output terminal 109 is set to "1". The ignition pulse generator 13 is an AND gate 3
When the eight output terminals 118 are "1", a firing pulse is generated. The ignition pulse generator 14 generates an ignition pulse when the output terminal 119 of the AND gate 39 is "1". The firing pulse transformers 11, 12 are firing pulse generators 13, 1
The ignition pulse generated by _No. 4 is applied to the thyristor circuits St ₁ and St ₂
Transmit to. Thyristors 7 and 8 are thyristor circuits St ₁
And the thyristors 9 and 10 are the switching elements of the thyristor circuit St ₂ . As an initial state, as shown in FIG. 8, the main contactor 3 is closed, and the main contactor 4 and the auxiliary contactors 5 and 6 are open. At this time, the output of the status annunciators 20, 21, 22, 23 is "1" at the output terminal 100, "0" at the output terminal 101, and the output terminal 1 respectively.
02 is "0", output terminal 103 is "1", output terminal 10
4 is "0", the output terminal 105 is "1", and the auxiliary contacts 5 and 6 are open, the thyristor circuits St ₁ and S
Output terminals 106 and 107 of the status annunciators 24 and 25 no voltage is applied to t ₂ both become "0". Therefore, the output terminal 108 of the storage element 15 is “1”, and the output terminal 10
9 is "0", the output terminals 110, 111, 112, 113 of the AND gates 26, 27, 30, 31 are all "0",
The output terminal 114 of the OR gate 34 is "1", the output terminal 1
15 is "0", the output terminal 116 of the OR gate 35 is "0", the output terminal 117 is "1", the output terminal 118 of the AND gate 38 is "1", and the output terminal 119 of the AND gate 39 is "0". . The state at this time is shown in the first column of the state column of Table 1.

Since the output terminal 118 of the AND gate 38 is "1", the firing pulse generator 13 generates a firing pulse and closes the thyristor circuit St ₁ .

Next, when the auxiliary contactor 5 is closed, the output terminal 102 of the status alarm 22 changes from "0" to "1" and the output terminal 103 of the status alarm 22 is "1".
Changes to “0” and the thyristor St ₁ is bypassed by the main contactor 3, so that the output signal 106 of the state alarm 24 is changed.
Remains "0". The state at this time is shown in the second column of the state column of Table 1.

Next, when the main contactor 3 is opened, the thyristor circuit St ₁ is closed, so that the current flowing through the main contactor 3 flows through the thyristor circuit St ₁ . At this time, the output terminal 100 of the status alarm 20 changes from "1" to "0". Since the thyristor circuit St ₁ is closed in the state alarm 24, no voltage is detected and the output terminal 106 remains “0”. This state is shown in the third column of the state column of Table I.

Next, when the auxiliary contactor 6 is closed, the flow path of the current from the thyristor circuit St ₁ to the thyristor circuit St ₂ is changed to the next 3
It is done in one step.

In the first step, the output terminal 104 of the status annunciator 23 changes from “0” to “1”, the output terminal 105 changes from “1” to “0”, and the thyristor circuit St ₂ is in the open state. The output terminal 107 of the alarm 25 changes from "0" to "1". Therefore, the output terminal 114 of the OR gate 34 changes from “1” to “0”, the output terminal 115 changes from “0” to “1”, the pulse generation of the ignition pulse generator 13 is stopped, and the thyristor circuit St ₁ is turned on. Open This state is shown in column 4a of the state column of Table I.

Since the thyristor circuit St ₁ is opened in the second step, the state alarm 24 detects the voltage and the output terminal 106 changes from “0” to “1”. Therefore AND gate 27
Output terminal 111 of "0" to "1", OR gate 35
Output terminal 116 is from “0” to “1”, and output terminal 117
Changes from "1" to "0", and the output terminal 119 of the AND gate 39 also changes from "0" to "1". Since the output terminal 119 of the firing pulse generator 14 is "1",
A firing pulse is generated and the thyristor circuit St ₂ is closed. This state is shown in column 4b of the state column of Table I.

Since the thyristor circuit St ₂ is closed in the third step, the state alarm 25 does not detect the voltage and the output terminal 107 changes from “1” to “0”. This state is shown in column 4c of the state column of Table I.

The first to third steps described above proceed instantaneously.

Next, when the auxiliary switch 5 is opened, the output terminal 102 of the status alarm 22 changes from "1" to "0", the output terminal 103 changes from "0" to "1", and the output of the status alarm 24 is changed. The terminal 106 changes from "1" to "0". Therefore, the output terminal 111 of the AND gate 27 changes from "1" to "0", and the output terminal 113 of the AND gate 31 changes from "0" to "1". This state is shown in column 5 of the state column of Table I.

Next, when the main contactor 4 is closed, the output terminal 101 of the status alarm 21 changes from "0" to "1". Therefore, the storage element 15 stores "0", the output terminal 108 changes from "1" to "0", and the output terminal 109 changes from "0" to "1". This state is shown in column 6 of the state column of Table I. Next, when the auxiliary contactor 6 is opened, the output terminal 1 of the status alarm 23
04 changes from "1" to "0", and the output terminal 105 changes from "0" to "1". Therefore, the output terminal 113 of the AND gate 31 changes from "1" to "0". This state is No. 1
It is shown in the 7th column of the state column of the table.

The taps are switched by the above steps.

[Problems to be solved by the invention]

As described above, the conventional tap switching device during load has the main contacts 3 and 4, the auxiliary contacts 5 and 6, and the thyristor circuit St.
_Since a large number of status alarms 20, 21, 22, 23, 24, 25 for detecting the respective conduction states of ₁ and St ₂ are required, the apparatus becomes complicated and, as a result, the reliability becomes low. .

[Means for solving problems]

The tap switching device during load according to the present invention has first and second movable contacts that are in contact with the output terminal through the voltage limiting element, and first and second movable contacts that are in contact with the output terminal through the semiconductor switch. And a tap selector comprising a third movable contact provided between the movable contacts, further between the first and third movable contacts and between the second and third movable contacts. First and second voltage detection devices are respectively arranged to control the opening and closing of the semiconductor switch according to the states of the voltages detected by the two sets of voltage detectors.

[Action]

For the opening and closing of the semiconductor switch, the semiconductor switch is "closed" when both the first and second voltage detection devices detect no voltage, and either the first or second voltage detection device detects the voltage. In this case, the semiconductor switch is controlled to be "open" or "closed", and when both the first and second voltage detection devices detect the voltage, the semiconductor switch is controlled to be "open".

〔Example〕

An embodiment of the tap changer under load according to the present invention is shown in FIG. In the figure, 51 is a tap winding of a transformer having a plurality of taps, 52 is an upper fixed contact connected to an upper tap at any position of the transformer tap winding 51, and 53 is an upper fixed contact. The fixed contactors 52 and 53 are fixed at a predetermined interval with lower fixed contactors connected to the taps adjacent to the lower side of the taps connected to the child 52. A tap selector 50 has first, second, and third movable contacts 54, 55, 56 that contact the fixed contacts 52, 53 to select a tap. The second movable contact 55 is connected to one end of voltage limiting elements 57 and 58 composed of a non-linear resistor such as zinc oxide, and the third movable contact 56 is provided with a pair of thyristor elements which are opposite to each other. One ends of the semiconductor switches 59 connected in parallel are connected, and the other ends of the voltage limiting elements 57 and 58 and the other ends of the semiconductor switches 59 are commonly connected and connected to the output terminal 60. It is output from the output terminal 60. The first, second, and third movable contacts 54, 55, 56 have the third movable contact 56 as the center,
The first and second movable contacts 54, 55 are arranged in front of and behind them, and between the first movable contact 54 and the third movable contact 56 and between the second movable contact 55 and the third movable contact. Between the contact 56 and the fixed contact 52 and 53 which are adjacent to each other, the fixed contact 52, 53 moves while maintaining a bridging distance, and when the tap is selected, the fixed contact 52, 53 moves to the first, second and third positions. Three movable contacts 54,
Fixed contact 5 with 55 and 56 connected to the selected tap
All are in contact with 2 or 53. The voltage limiting elements 57 and 58 have the voltage-current characteristics shown in FIG. 3, and the current element range shown in the figure is larger than the instantaneous maximum value of the voltage between adjacent taps, and the limiting voltage range is for any tap. It is set to a value lower than the ground voltage. 61 is a first movable contactor 54 and a third movable contactor 5.
6 is a first voltage detection device that is connected between the second movable contact 55 and the third movable contact 56, and is connected between the second movable contact 55 and the third movable contact 56. This is a second voltage detection device for detecting a potential difference, and has output terminals 63 and 64, respectively. The first and second voltage detection devices do not operate due to the potential difference due to the voltage drop of the semiconductor switch during energization. Reference numeral 65 denotes an ignition control device which outputs an ignition control signal for controlling the opening and closing of the semiconductor switch 59, and which has an output terminal 66, and outputs a signal detected by the first and second voltage detection devices 61, 62 to detect the presence or absence of voltage. Upon receipt, it outputs an ignition control signal for the semiconductor switch. 67 receives an ignition control signal from the output terminal 66 of the ignition control device 65, outputs an ignition command signal to the semiconductor switch 59 through its output terminal 68, and controls the opening / closing of the semiconductor switch 59. Is. FIG. 4 shows the configuration of the ignition control device.

The inverters 71 and 72 include the first and third movable contacts 5
An output V _{1 of} the first voltage detection device 61 that detects the presence or absence of a potential difference between the second and third movable contacts 55,
Second voltage detection device 6 for detecting the presence or absence of a potential difference between 56
The outputs V ₂ of ₂ are inverted to ₁ and ₂ , respectively. The outputs of the AND gates 73, 74, 75, 78, 79 and 80 are represented by A, B, C, F, G and H, respectively. The flip-flops 76, 77, 83 have an output Q and an R having an inverted output.
-S flip-flop, which outputs two sets of outputs of the flip-flop 76 to D and the flip-flop 77, respectively.
2 sets of outputs of E and the flip-flop 8
The output of 3 is represented by K. The outputs of the OR gates 81 and 82 are represented by I and J, respectively. First and second voltage detectors 61,
The outputs V ₁ and V ₂ when 62 detects a voltage are set to logic level 1 (hereinafter referred to as “1”), and the outputs V ₁ and V ₂ when they are not detected are set to logic level 0 (hereinafter referred to as “1”). "0"). The ignition device 67 for controlling the semiconductor switch 59 operates to close the semiconductor switch 59 when the output K of the flip-flop 83 of the ignition controller 65 is "1", and when it is "0". It is configured to be "open". FIG. 5 shows the steps of each operation of this embodiment, and FIG. 2 shows the first, second and third steps.
7 is a timing chart of the movable contacts 54, 55 and 56 of FIG. In this figure, the ignition control device 65 and the ignition device 67 are omitted. FIG. 5 a shows a state in which the upper fixed contactor 52 is connected to the output terminal 60. First, second and third movable contacts 54, 55, 56
Since both are in contact with the upper fixed contact 52,
Also, the potential difference between the second voltage detectors 61 and 62 is not detected, and the outputs V ₁ and V ₂ are both “0”. Therefore, the outputs ₁ and ₂ of the inverters 71 and 72 shown in FIG. 4 are both "1", the output A of the AND gate 73 becomes "1", and the output I of the OR gate 81 also becomes "1". The outputs B and C of the AND gates 74 and 75 are both "0".
Therefore, the output D of the flip-flop 76 becomes "0",
Is "1", and the output E of the flip-flop 77 is "1" instead of "0". AND gate 79,
The outputs G and H of 80 are both "0", the output J of the OR gate 82 is "0", and the output I of the OR gate 81 is I.
Is "1", the output K of the flip-flop 83 becomes "1", and the ignition control device 65 drives the ignition device 67 to close the semiconductor switch 59. At this time, the load current is the upper fixed contact 52, the third movable contact 56,
It flows through the path of the semiconductor switch 59 and the output terminal 60.
Next, until the second movable contact 55 separates from the upper fixed contact 52 and contacts the lower fixed contact 53,
Since the second voltage detectors 61 and 62 do not detect the potential difference, both outputs V ₁ and V ₂ are “0”, and the semiconductor switch 59 remains “closed”. As shown in FIG. 5 b, the second movable contact 55 is a lower fixed contact 53.
When the second voltage detector 62 contacts the fixed contact 5
When the potential difference between 2 and 53 is detected, the output V ₂ becomes "1".

Therefore, the ignition control device 65 has the output _{1 of} the inverter 71.
Is "1", the output ₂ of the inverter 72 is "0", the outputs A and C of the AND gates 73 and 75 are both "0", the output B of the AND gate 74 is "1", and the output D of the flip-flop 76 is Is "1" and is "0".
Further, since the output E of the flip-flop 77 remains "0" and "1", the output G of the AND gate 79 becomes "1" and the outputs F and H of the AND gates 78 and 80 become "0". Therefore, the output I of the OR gate 81 is "0" and the output J of the OR gate 82 is "1".
The output K of the flip-flop 83 becomes "0", and the ignition control device 65 stops the ignition device 67 to turn on the semiconductor switch 59.
Is "open". The state at this time is shown in FIG. 5C. At this time, the load current is the tap winding 51, the upper fixed contact 5
2, first movable contactor 54, voltage limiting element 57, first path flowing through output terminal 60, tap winding 51, lower fixed contactor 53, second movable contactor 55, voltage limiting element 58 and the second terminal flowing through the output terminal 60. Since the current blocking voltage range of the voltage limiting elements 57 and 58 is larger than the instantaneous maximum value of the potential difference between the adjacent voltage taps as described above, the inter-tap bridging is performed between the fixed contacts 52 and 53 via the voltage limiting elements 57 and 58. No current flows. Next, when the third movable contact 56 leaves the upper fixed contact 52, the semiconductor switch 59 is already “open”, and the first and second voltage detection devices 6
Since the currents flowing through 1 and 62 are so small that they can be ignored, almost no arc is generated. Until the third movable contact 56 leaves the upper fixed contact 52 and contacts the lower fixed contact 53, the first and second voltage detection devices 61 and 62.
Detects a voltage which is approximately one half of the potential difference between the fixed contacts 52 and 53, the outputs of both are "1" and the outputs of the inverters 71 and 72 are "0". Therefore, the outputs A, B, C of the AND gates 73, 74, 75 are all "0", but the states of the flip-flops 76, 77 do not change, so the output K of the flip-flop 83 remains "0" and the semiconductor switching operation is performed. The container 59 is kept in the "open" state. The state where the third movable contactor 56 contacts the lower fixed contactor 53 is shown in FIG. 5d.
In this state, the first voltage detecting device 61 detects the potential difference between the upper fixed contact 52 and the lower fixed contact 53, so that its output V ₁ is “1”, and the second voltage detecting device 6
Since 2 does not detect the voltage, its output V ₂ becomes "0". Therefore, the output ₁ of the inverter 71 of the ignition control device 65 shown in FIG. 4 is "0", the output ₂ of the inverter 72 is "1", and the outputs A and B of the AND gates 73 and 74 are both "0" and AND. The output C of the gate 75 becomes "1". Since A is "0", the flip-flop 76 holds the state up to that point, and the outputs D, are maintained in the states of "1" and "0", respectively. Further, since the output C of the flip-flop 77 becomes "1", its output E becomes "1" and becomes "0", and the output F of the AND gate 78 becomes
Is "1", and the outputs G and H of the AND gates 79 and 80 are both "0". Therefore, the output I of the OR gate 81 is "1", the output J of the OR gate 82 is "0", the output K of the flip-flop 83 is "1", and the ignition control device 65 closes the semiconductor switch 59. . This state is shown in FIG. 5e. At this time, the load current is 5
1, the lower fixed contactor 53, the semiconductor switch 59, and the output terminal 60. At this time, the inter-tap bridging current due to the potential difference between the upper and lower fixed contacts 52 and 53 does not flow through the voltage control element 57 as described above. Next, the first movable contactor 54 is the upper fixed contactor 5.
2, but no current flows through the first movable contactor 54, no arc is generated. Further, since the first and second voltage detecting devices 61 and 62 do not detect the voltage, both outputs V ₁ and V ₂ thereof are “0”, which is the same as the state of FIG. Maintain the "closed" state. Next, the first movable contactor 54 is the lower fixed contactor 53.
And the state of FIG. 5f is reached, and the switching operation of lowering the tap is completed. FIG. 6 is a timing chart of the series of operations described above. The switching operation for raising the tap can be performed in the same manner as in the case of lowering. FIG. 7 shows a timing chart in the case of rising.

〔The invention's effect〕

According to the present invention, the open / close control of the semiconductor switch of the tap change device during load is controlled by the first and second voltage detection devices provided between the first and third and second and third movable contacts. Is detected and the semiconductor switch is opened / closed depending on the presence / absence of a voltage, a state alarm for detecting the open / closed state of the contact is unnecessary, and the structure of the device is simple and inexpensive. Further, reliability can be improved because stable operation can be performed even at high speed switching.

[Brief description of drawings]

FIG. 1 is a diagram showing the structure of the tap changer during load of the present invention, FIG. 2 is a timing chart showing the operation of the movable contactor of the present invention, and FIG. 3 is used for the tap changeover device of the present invention. Diagram showing the current-voltage characteristics of the voltage limiting element,
FIG. 4 is a diagram showing a structure of an ignition control device for a semiconductor switch of a load tap switching device of the present invention, and FIG. 5 is a diagram showing respective steps of a switching operation of the load tap switching device of the present invention. FIG. 6 is a timing chart of the tap lowering operation of the load tap switching device of the present invention, and FIG. 7 is a tap raising operation timing chart of the load tap switching device of the present invention, in the opposite direction to the operation shown in FIG. FIG. 8 is a timing chart of the operation, FIG. 8 is a diagram showing a main circuit of a conventional load tap switching device, and FIG. 9 is a diagram showing a control circuit of an ignition device of a semiconductor switch of the conventional load tap switching device. . 52, 53 ... Fixed contact, 54, 55, 56 ... Movable contact, 57, 58 ... Voltage limiting element, 59 ... Semiconductor switch,
60 ... Output terminals, 61, 62 ... Voltage detection device.

Claims (1)

[Claims] 1. A plurality of fixed contacts, which are connected to the respective taps of a winding having a plurality of taps and are arranged at regular intervals with a predetermined distance, and a tap is selected by contacting the fixed contacts. Having first, second and third movable contactors,
The first movable contactor and the second movable contactor are each connected to one end of a voltage limiting element having a limit voltage higher than a voltage between adjacent taps and lower than a ground voltage of any of the taps. One end of a semiconductor switch in which a pair of thyristor elements are connected in antiparallel to each other is connected to the third movable contact, and the other end of each voltage limiting element and the other end of the semiconductor switch are commonly output. The movable contactor is connected to a terminal, and each movable contactor has a first movable contactor and a second movable contactor disposed in front of and behind the third movable contactor as a center. Between the third movable contactor and the second
Between the movable contact and the third movable contact while maintaining a bridging gap between the adjacent fixed contacts, and when the tap is selected, the first, second and third movable contacts are moved. The child is connected between the tap selector configured to make all contact with the fixed contacts connected to the selected tap, and the first movable contact and the third movable contact, and between them. A first voltage detecting device for detecting a potential difference, a second movable contactor and a third
A second voltage detection device connected between the movable contactor and the second voltage detection device for detecting a potential difference therebetween, and an ignition for controlling the opening and closing of the semiconductor switch by the detection signals of the first and second voltage detection devices. Control means, the first and second voltage detection devices do not perform detection operation due to a potential difference due to a voltage drop of a semiconductor switch that is being energized, and the ignition control means includes first and second When both of the voltage detecting devices detect no voltage, the semiconductor switch is kept closed, and one of the first and second voltage detecting devices detects no voltage. When it is detected, the semiconductor switch is changed from the closed state to the open state, and the first and second voltage detecting devices detect the voltage, and one of them stops detecting the voltage. Open the semiconductor switch Load tap switching device which is characterized in that the control of the closed state from the state.