JPS6094710A - On-load tap changer - Google Patents

Abstract

PURPOSE:To enhance the reliability by reduction of the power consumption and alleviation of the required insulation strength of a power source transformer by a method wherein the titled device is so constructed as to obtain the auxiliary circuit power source for driving a thyristor switch from the tap selection contact side. CONSTITUTION:In the case of tap switching from the state of using the tap B to that of using the tap 1C, first the tap selection contact 2A is moved above the tap 1B by operating a contact drive 8, thus putting the contact to the same potential as that of a conduction contact 2C. Since the contact 2B slides onto the electrode of the tap 1C on transfer of the contact 2A onto its electrode, a tap voltage Vs is impressed on the primary side of an auxiliary circuit power source transformer 5. When the power source of gate control circuits 4A and 4B is secured, then ignition pulses are generated to the thyristors 1a and 3c of the thyristor switch 3A from the circuit 4A, and, in the state of generating these pulses, the contacts 2A and 2B are transferred to the electrode centers of the taps 1B and 1C by the contact drive, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a power supply for controlling a semiconductor switch edge of an on-load tap changer using a semiconductor switch such as a thyristor switch.

[Prior art]

Figure 1 shows the basic circuit of an on-load tap changer using anti-parallel thyrisk switches.

In this figure, the main transformer, LA, 113. IC is main transformer 1 tap, 2 people,
2B is a tap selection contact, 3A, 313 is a thyrisk switch formed by connecting thyrisks in antiparallel, 3a, 3
b, 3c, 3d are cyrisks, 4Δ, 4B are gate control circuits 173, 5 are power transformers for auxiliary circuits, that is, gate control circuits, 6 are overcurrent control handles, 7 is main transformer 1
8 is a contact drive mechanism. In addition, FIG. 2 shows the waveform of the inter-tap voltage Vs and the negative current I having a phase of θ with respect to the voltage Vs.

In this configuration, the electrical tap switching operation is performed as follows. Now, tap select ”l touch 2A, 2B
As shown in the figure, taps IA and 113 are selected respectively, and the thyristor 3b of the switch 3Δ is turned on by the gate control circuit 4A. indicates the main circuit voltage.

In this state, when a firing pulse Ij is applied from the gate control circuit 4B to the thyristor 3d of the switch 3B at time to shown in FIG. 2, the thyristor 3d fires,
Tap IB-Thyristor 3d-Reactor 5-Load 6-
An inter-tap circulating current flows between the thyristor 3b and the tap IA, the thyristor 3a is turned off and the thyristor 3b is turned on, and from then on, a current (2) is applied to the load 7 through the tap IB.

In this way, tap switching is performed by controlling the thyristor switches 3A and 3B, but the gate control circuits 4A and 4B, which generate firing pulses to turn on and off these thyristor switches, have their own power supply. Since the inter-tap voltage Vs taken out from the taps IA and IB via the power transformer 5 is given as the voltage, the gate control circuit 4A,
The power transformer 5 is excited even during a period when it is not necessary to drive 4B. For this reason, power is wasted, which is not only uneconomical, but also has the disadvantage that reliability quickly deteriorates after long-term use.

Also, this auxiliary power transformer 5 is fixed because it is connected to the taps IA and IB, but the tap selection contact 2
Since A and 2B are located in the rotating movable part of the tap changer, there is a drawback that the auxiliary circuit power transformer 5 needs to have a dielectric strength higher than 1".

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones described above, and connects an auxiliary circuit power transformer to the tap selection contact l-(1111), and uses the output of the nuclear power transformer to drive a thyristor switch, etc. The 1'J, 4 o'clock tap changer can reduce power consumption and reduce the required dielectric strength of the power transformer, increasing reliability compared to conventional products. This is what we propose.

[Embodiments of the invention]

FIG. 3 is a diagram showing times 1 to 3 of an embodiment of the present invention, in which an auxiliary circuit auxiliary power transformer 5 is connected between tap selection contacts 2A and 2B, and a current-carrying contact 2C is added. It differs from the one shown in FIG. 1 in this respect. Each contact drive device 8 is operated 41 times.

Mechanically, the current-carrying contact 2C is arranged in parallel between the tap selection contacts 2A and 2B so as to be able to contact the electrodes of the taps IA, IB, and IC at a spatial distance of X from both of them, and is electrically connected to the electrodes of the taps. It is connected to the middle point O of the axle 6. This spatial distance X has a relationship of Y>X>Z with respect to the electrode distance (slide distance) Y in the arrangement direction of the taps IA, IB, and IC and the interelectrode capacity mz.

Next, the tap switching operation of this tap changer is shown in Fig. 4 fa.
) to (e) and the fifth section showing the phase relationship between the voltage Vs and the current I.
This will be explained with reference to the figures.

Figure 4 fa) shows that power is supplied to load 7 from tap IB of transformer 1.
The current-carrying contact 2c is in the current-carrying position where it contacts the center of the electrode of the tap IB, and the current I is flowing to the load 7 through the current-carrying contact 2C.

When switching the tap from the tap IB of FIG. 3 +al to the tap IC, first operate the contact drive device 8 and move the tap selection contact 2A to the tap IB as shown in FIG. 3(b). Move the two contacts upward (tap switching preparation step) 1
Make it the same potential as the 11-volt contact 2C. When the tap selection contact 28 is moved up to the distribution electrode, the tap selection 1) wire 1 contact 213 slides onto the electrode of the tap IC. 1i pressure Vs is applied. In this way, when the power supply of the gate control circuit 17114Δ, 413 is established, the thyristor 1a and 3G to the thyristor isochi 3 are caused to generate an ignition pulse from the gate control circuit 48, and the ignition pulse is generated. With the contact I-driver still in place, the tap selection contact I-driver as shown in FIG.
Move the two people and 2B to the tap 1B and the center of the IC electrode (Tarapuri J exchange step). During this movement, the current-carrying contact 2C separates from the electrode of the tap 113, and due to the arc current 11- and the firing pulse of the thyristor at the time of separation, the ON condition for the thyristor Sochi 3 is established, and the J 'Iristor 3a or 3C turns on. For example, at time t1 of the 5th I'y, I, if the condition is met, the beam/iris resistor 3C turns on and the load current I
If so, the current will flow through the risk switch 38.

Therefore, when a firing pulse is supplied to the thyristor 3d of the thyristor switch 3B at time t2, the thyristor 3d is turned on, and the tap IC - thyristor 3d - reactor 6 -
An inter-tap circulating current flows between Thyrisk 3C and tap IB, turning off Thyrisk 3C, and current begins to flow to load 7 through Thyristor 3d. An ignition pulse is applied to the thyristor 3b at the same time as an ignition pulse to the thyristor 3d.

Next, as shown in FIG. 4fdl, the current-carrying contact 2C
is moved onto the electrode of tap C (thyrisk switch shorting step) and made to have the same potential as tap selection contact 1-2B. Since the voltage drop of current-carrying contact 2C is smaller than the voltage drop of Cyrisk switch 3B, current-carrying contact 2C
The thyristor switch 2B is short-circuited, the thyristor switch 2B is turned off, and the load current begins to flow through the current-carrying switch 2C. When the load current is transferred to the current-carrying contact 2C, the tap selection contact 2B is separated from the tap IC as shown in FIG. (The 9' cycle of all tap switching is completed by using the illJ Den Stella Step, and from then on, the tap IC
A load current flows to the load 7 via the energizing ml connector) 2C. Tap selection contact!・When 2B leaves the tap IC, the tap selection contact l-2A also becomes the tap IB.
Since the auxiliary circuit power transformer 5 is separated from the auxiliary circuit, the auxiliary circuit power transformer 5 becomes non-excited.

In this embodiment, the auxiliary circuit power transformer 5 is connected to the movable side tap selection contacts 2A, 2 [3, so the dielectric strength of the auxiliary circuit power transformer 5 is based on the voltage value between the taps. It only needs to be determined, and it is much easier than the conventional case.
It can be reduced to 1. That is, in the conventional case, the auxiliary circuit power transformer 5 is at the same potential as the gate of the SIRISK, so when the number of taps on the main transformer 1 increases, the voltage from the lowest potential tap to the highest potential tap increases. In this embodiment, it is sufficient to have insulation ability for the voltage value between one tap. This results in an easier gate pulse transformer for thyristor firing.

In this embodiment, a current-carrying contact 2C is provided and a load current is passed through the current-carrying contact, and two tap switching contacts, 2B, are in the tap switching operation, that is, the contact group is in the tap switching preparation step and the tap switching step. ,
Since the sirisk switch is connected to the tap of the main transformer 1 only during the short-circuit step, the auxiliary circuit power transformer 5 is connected to the tap of the main transformer 1 during this tap switching operation (the number of circuit voltage frequencies + several hundred cycles of the cyrisk switch). The no-load loss of the auxiliary circuit power transformer 5 is reduced because the auxiliary circuit power transformer 5 is energized only for a short period of time) and is not energized when the load is energized through the energizing contact 2C.

Note that the output of the auxiliary circuit power transformer 5 can also be used as a monitoring power source for protecting the thyrisk switch.

〔Effect of the invention〕

As explained above, this invention has a configuration in which the power supply for the auxiliary circuit for driving the thyrisk switch is obtained from the tap selection contact side, thereby reducing the required dielectric strength of the power supply device for the auxiliary circuit compared to the conventional one. can do.

In addition, by adding a negative (jmm) mikotact that controls energization to the contact set, and making the conventional tap selection contact responsible only for tap switching operation, the power consumption of the auxiliary circuit power supply is reduced compared to the conventional one. In addition to being able to reduce the amount of damage during a long period of time, it is also possible to prevent a decrease in reliability over one period compared to the conventional method.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing a conventional on-load tap changer;
4 is a waveform diagram, FIG. 3 is a circuit diagram showing an embodiment of the present invention, FIG. The figure is a waveform diagram. In the figure, 2A, 2B - tap selection contact, 2C - current carrying contact, 3A, 3B - thyrisk switch, 3a to 3d - thyrisk, 48, 4B - gate control circuit, 5 - power supply transformer for auxiliary circuit. device, 8-contact drive device. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa 2 Figure 3 Figure 5 Figure V=. Commissioner of the Japan Patent Office ``Yuki (6)'' Person 5, subject of amendment (1) Claims column of the specification (2) I'ptm explanation of the invention in the specification 1lf16
, Contents of amendment (1) The scope of claims in the specification is corrected as shown in the attached sheet. (2) "Thyristor 3bJ of switch 3A [thyristor 3CJ of switch 3A]" on page 3, lines 15 to 16
I am corrected. (3) "Ignition pulse" on page 3, line 16 and line 700, line 9 is corrected to "ignition pulse". (4) [Lee Ilista 3 (
]-] Reactor 5 - Load 6 - Thyristor 3b = inter-tap circulating current flows through tap I, thyristor 3a is turned off,
Thyristor 3I) turns on, "Thyristor 3d - reactor 6 - Thyrisk 3cm Tap circulating current flows through tap IA, Thyrisk 3C turns off, Thyrisk 3d
is on,” he corrected. (5) On page 5, line 2, 1 is required.'' 1 is required.''
I am corrected. (6) Change “Figure 3 (a)” in line 16 of page 6 to “Figure 4 (a)” and change “Figure 3 (b)” to “Figure 4 (a)” in line 18 of the same page.
b)” respectively. (7) On page 6, line 19, "Tap IB up" is corrected to "Tap IB up". (8) In the 3rd line of page 7, ``When moving upwards'' is corrected to ``When moving upwards''. (9) [Thyristors 1a and 3CJ] on page 7, line 8
Correct to thyristors 3a and 3CJ. 00) "Figure 3 (C)" on page 7, line 11 of the same page is replaced with figure 14 (C).
)” is corrected. (11) On page 7, line 12 [tap IB, I, respectively]
CJ is corrected as tap IB and IcJ, respectively. (12) "The thyristor 3.dJ" in the third line of page 8 is corrected to ``the thyristor 3dJ.'' Claims (1) A set of tap selection contacts that are co-operated in the transformer tap arrangement direction. A 1'1 tap changer which switches the main transformer tap by controlling the ?1' conductor switches connected to each of the tap selection A1-tacts, and which is connected to each of the tap selection contacts. fl, (i:i II, -tap changer) characterized in that an auxiliary circuit power transformer is connected, and the output of the power transformer is used as a control power source for the semiconductor switch. (2) Transformer tap In the on-load tap changer, the main transformer tap is controlled by switching the semiconductor switches connected to each of the tap selection 2-z tacts, and is provided with a set of tap selection contacts that are moved together in the arrangement direction. A power supply contact (=J) is added to the pair of tabs selected, and a power transformer, which is the drive power source for the semiconductor switch, is connected to both tap selection contacts, and the load during non-tap switching is Energization is carried out through the second energizing contact, while tap switching is carried out by the -1- tab selection contact I. When transitioning from the f'I charge energization to the tap IJJ IN, the set of contacts One of the tap selection contacts is driven and slid onto the electrode of the tap that is in contact with the current-carrying contact, and after controlling the switching of the semiconductor switch, the other tap selection contact is slid onto the electrode of the tap that is in contact with the current-carrying contact. An on-load tap changer characterized in that the state is shifted to the non-tap switching state by the current-carrying contact through a step in which the current-carrying contact is slid.

Claims (1)

[Claims] +11 A load that is provided with tap selection contacts in the form of silk that move together in the direction of the arrangement of the transformer taps, and that switches the main transformer taps by controlling the switching of semiconductor switches connected to each of the tap selection contacts. A negative time tap changer, characterized in that an auxiliary circuit power transformer is connected to the tap selection contact, and the output of the power transformer is used as a control power source for the semiconductor switch. (2) The main transformer tap is switched by providing a set of tap selection contacts I that are operated together in the direction of the transformer tap arrangement, and controlling the switching of the semiconductor switches connected to each of the tap selection contacts. In the tap changer,
A current-carrying contact is added to the set of tap selection contacts (1), and a power transformer serving as a driving power source for the semiconductor switch is connected to both tap selection contacts, and the load is energized through the current-carrying contact during non-tap switching. On the other hand, tap switching is performed by the tap selection contact, and when transitioning from the load energization to the tap switching, the set of contacts is driven to select the tap on the electrode of the tap that is in contact with the energization contact. One of the contacts is slid, and after controlling the switching of the semiconductor switch, the current-carrying contact is slid onto the electrode of the tap that is in contact with the other tap selection contact, and the above-mentioned non-switching/7-pipe switching is performed by the current-carrying contact. An on-load tap changer characterized by changing the time state.