JPH0452603B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to an on-load tap changer.

[Technical background of the invention and its problems]

In recent years, electric power equipment has become increasingly high-voltage and large-capacity, but on the other hand, the greatest demand is for equipment to be smaller, lighter, and cheaper to manufacture, and on-load tap changers are one of these requirements. By the way, the conventional load tap changer has an electric operation mechanism that drives the load tap changer based on a signal from a control device that detects and controls the rise and fall of electric charge, and this electric operation mechanism applies energy to a storage spring. an energy storage device that stores energy; a switching switch that rotates at a predetermined speed using the released energy of the energy storage device to cut off the current; It is the most common because it consists of a tap selector that makes tap selections depending on the state.

If we continue to technically pursue the on-load tap changer configured in this way, we will need a selector that selects the cut-off part of the switching switch that cuts off the current when the load is on, and the tap of the tap winding of the transformer. It is a minimal device, and there is no problem in replacing the other energy storage device and electric operation mechanism with other suitable devices, but rather it is an obstacle to making these devices smaller, lighter, and cheaper. It was a contributing factor.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and
The purpose is to provide a load tap changer that is small and lightweight and can be manufactured at low cost.

[Summary of the invention]

According to the present invention, in order to achieve such an objective,
By using a servo motor as the drive source, detecting the point at which the movable contact of the switching switch's interrupting part closes and closes, and controlling the speed of the servo motor, it can be made smaller, lighter, and cheaper. is its characteristic.

[Embodiments of the invention]

An embodiment of the on-load tap changer according to the present invention will be described below with reference to FIGS. 1 to 3. In Figure 1, the on-load tap changer is tap changer 1.
, a position detector 3 connected to this via a reduction gear device 2, and a servo motor 5 connected to this
and a control device 6 that controls the speed of the servo motor 5 in accordance with the detection signal of the position detector 3.

The tap changer 1 is constructed as follows. That is, a plurality of taps T ₁ , T ₂ ... _To (only T ₁ and T ₂ in the illustration) of the tap winding TW connected to the transformer winding (not shown) are placed on the panel 7 made of an insulating material. Fixed contacts S ₁ , S ₂ ...S _o connected to
are arranged at equal intervals around the circumference. These fixed contacts S ₁ , S ₂
...An insulating plate 10 is attached to the rotating shaft 8 via a movable contact support member 9 approximately at the center of the circumference of S _o . One side of this insulating plate 10 is in sliding contact with a fixed contact, and the other side is a current collector ring 11, 1 formed concentrically.
Movable contacts M ₁ and M 2 are attached to sliding contacts M 2 and M ₂ , respectively. In addition, the current collecting rings 11 and 12 are fixed to the panel 7, and connected to the current limiting reactor via lead wires.
Wl is connected to the output terminal side (not shown) via the lead wire from the midpoint of the current limiting reactor Wl.
connected to. Then, a interrupting section is formed between the movable contacts M ₁ , M ₂ and the fixed contacts S ₁ , _{S 2} .

The rotating shaft 8 of the cut-off part and the fixed contact of this cut-off part
S ₁ , S ₂ . . . A position detector 3 that detects the open/close positions of S _o and movable contacts M ₁ , M ₂ is connected to an insulating rod 13 and a gear 15 connected via a reduction gear device 2. It consists of a gear 16 that meshes with the gear 16. Note that the reduction gear device 2 and the load tap changer 1 are arranged with a partition plate 17 in between.

The position detector 3 includes a movable contact member 19 that is fixed to a drive shaft 18 that connects the gear 16 and the servo motor 5 and rotates together with the movable contact member 19, and a fixed contact member that is arranged to form a circumference around the drive shaft 18. contact member 20a,
20b. In the illustration, four fixed contact members 20a made of small arc-shaped contact members are provided at opposing positions, and two fixed contact members 20b made of relatively long arc-shaped contact members are provided at opposing positions. The four fixed contact members 20a are connected to the control device 6 at once, and the two fixed contact members 20b are also connected to the control device 6 at once. Also, the movable contact member 1
When the movable contact member 19 and the fixed contact member 20a are in sliding contact, it is designated as a, and when the movable contact member 19 and the fixed contact member 20b are in sliding contact, it is designated as b.
(See Fig. 3) The control device 6 includes a control device 25 connected to the position detector 3, and a current control device 2 receiving the output of the control device 25.
6 and a converter 27 receiving the output thereof,
This converter 27 includes a power source 28 and a rectifier 29. A converter 27 is connected and configured to control the servo motor 5. In the current control device 26, a of the fixed contact member 20a is
Alternatively, a current signal is sent to the converter 27 in response to the signal b at the fixed contact member 20b. The converter 27 that receives the current signal converts the frequency of the servo motor 5 according to the signal to freely change the number of revolutions of the servo motor 5.

Next, the operation of the present invention will be explained. First, the current control device 26 operates upon receiving a signal from a control panel (not shown), sends the signal to the converter 27, and rotates the servo motor 5. The rotation of the servo motor 5 causes the tap changer 1 to start operating, causing the movable contact member 19 of the position detector 3 and the movable contacts M ₁ and M ₂ of the tap selector 1 to rotate.

Further, the states of the movable contacts M ₁ , M ₂ and the fixed contacts S ₁ , S ₂ of the tap changer 1 shown in FIG. 1 are extracted and shown in FIG. 2. In this figure, a tap winding TW connected to a transformer winding (not shown) is provided with a plurality of taps T ₁ and T ₂ in the drawing. These taps T ₁ and T ₂ have fixed contacts S ₁ of the tap selector 1,
S ₂ is connected. Fixed contacts of tap selector S ₁ , S ₂
Connect the current-limiting reactor Wl to the movable contacts M ₁ and M ₂ that switch and contact. The figure shows tap _T1 selected. In the switching operation, the movable contact _M2 operates first, contacts the fixed contact _S1 , and short-circuits between the taps _T1 and _T2 . During this period, the short circuit current between the taps is limited by the current limiting reactor Wl.

FIG. 3 is a sequence diagram showing the relationship between the speeds of the movable contacts M ₁ and M ₂ , the position detector 3, and the movable contacts M ₁ and M ₂ . As described above, the movable contact member 19 of the position detector 3 is connected to the fixed contact member 20.
The time when it is in contact with a is designated as a, and the time when it is in contact with the fixed contact member 20b is designated as b. Then, when the movable contact member 19 of the position detector 3 comes into contact with the fixed contact member 20a, that is, at point a, the servo motor 5 rotates slightly faster than the initial speed to a speed _v1 under the control of the control device 6. The movable contact M ₂ then makes contact at the fixed contact member 20b, ie, b, slightly before the point at which it interrupts the current. When the fixed contact member 20b, ie, b, makes contact, the servo motor 5 further increases its speed to a speed _v2 , and the movable contact _M2 interrupts the current. Then, just before turning on the movable contact _M2 , the fixed contact member 20
b opens, that is, moves away from b. Then, the fixed contact member 20b is closed again. After decelerating to the speed v ₁ again, the movable contact M ₂ is connected to the fixed contact S ₂ .
Subsequently, when the fixed contact member 20a opens, the servo motor 5 further decelerates and stops. In this way, one-tap switching is completed.

The reason for changing the speed v ₁ to the speed v ₂ will be explained. First, the speed v ₂ must be such that the movable contact M ₁ or M ₂ interrupts the load current. If the speed v ₂ is slow, the firing time at the time of interruption becomes correspondingly long, which is not preferable because it results in increased wear and tear on the fixed contacts S ₁ , S ₂ . . . S _o and the movable contacts M ₁ , M ₂ . In addition, the speed v ₁ causes chattering due to the impact when the movable contacts M ₁ , M ₂ are applied to the fixed contacts S ₁ , S ₂ . . _{. So.} Such chattering causes arcing between the fixed and movable contacts in the same way as when the contacts are cut off, which has a negative effect on contact wear. In this way, the portion corresponding to the conventional electric mechanism section can be made smaller and lighter. Furthermore, costs can be reduced.

In the above-described embodiment, the tap changer cuts off the current, but the present invention can also be applied to a case where the tap changer switches without current. Further, although the current limiting reactor type has been described, it goes without saying that a current limiting resistor type can also be used.

〔Effect of the invention〕

As explained above, according to the present invention, the following advantages can be obtained.

(1) Conventional devices required an electric operating mechanism and an energy storage device. These mechanisms have complicated structures and use many machined parts, making them expensive, but the present invention uses a general-purpose servo motor, its control device, and a simple position detector, making it inexpensive. It can be manufactured.

(2) With conventional energy storage devices, the cut-off speed had to be changed depending on the current capacity of the tap changer being driven, so it was necessary to have a unique energy storage device. In the present invention, the shutoff speed can be freely changed by detection by the position detector, so
With only one type of position detector, it can be applied to other load tap changers.

(3) In addition, conventional devices generally use tension or compression springs, and if this spring were to break, it would become impossible to shut off, which could lead to a serious accident. Furthermore, in order to prevent this, it would be possible to perform an inspection, but since it is installed inside the transformer, inspection cannot be easily performed. On the other hand, in the present invention, since the device can be placed in the air, inspection is easy, and since it is directly connected to the servo motor, the reliability of the device is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram including a perspective view and a block diagram showing the configuration of the on-load tap changer of the present invention, FIG. 2 is an explanatory diagram of the tap selector of FIG. 1, and FIG.
FIG. 3 is a sequence diagram showing the operation of the speed and position detectors in accordance with the operation of the movable contact of the tap selector shown in FIGS. 1...Tap selector, 2...Reduction gear device, 3
... Position detector, 5 ... Servo motor, 6 ... Control device, 7 ... Panel, 8 ... Rotating shaft, 9 ... Movable contact support member, 10 ... Insulating plate, 11, 12 ...
...Current ring, 13...Insulation rod, 15, 16
... Gear, 17 ... Partition plate, 18 ... Drive shaft,
19... Movable contact member, 20a, 20b... Fixed contact member, 25... Control device, 26... Current control device, 27... Converter, 28... Power supply, 29...
Rectifier, TW...Tap winding, Wl...Current limiting reactor, _S1 , _S2 ~ S _o ...Fixed contact, _T1 , _T2 ...
Tap, _M1 , _M2 ...Movable contacts.

Claims (1)

[Claims] 1. A tap selector that selects a tap by contacting the tap of the transformer voltage tap winding, a interrupting section that is connected to this tap selector and interrupts the load current, and opening/closing of this interrupting section, fixed contact, and movable contact. a position detector for detecting a position; a control device for transmitting a speed control signal for the servo motor in response to a signal from the position detector; and a control device for freely converting the rotation speed in response to a signal from the control device; What is claimed is: 1. A load tap changer comprising: a servo motor that drives a tap selector;