JPH0245415B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an on-load tap changer, and more particularly to an improvement in an electrically operated operating mechanism for operating a tap changer.

[Technical background of the invention]

In general, a load tap changer includes a load tap changer 1 and an electric operating mechanism 2, as shown in FIG.
When the load 3 of the power transmission and distribution system fluctuates, the transformer 4 detects a voltage change corresponding to the fluctuation, and when the amount of change exceeds a certain value, the on-load tap switching device operates. By creating a command in the on-load tap switching device operation command generation circuit 5 and driving the electric operating mechanism 2, the taps provided on the on-load tap switching transformer 6 are switched by the on-load tap switching device 1 and transmitted. It has the function of keeping the voltage of the power distribution system constant.

In such a load tap switching device, the conventional electric operation mechanism 2 includes an electric motor 7 that generates the power necessary for operating the load tap changer 1 as shown in the figure, and a motor 7 that generates the power necessary for operating the load tap changer 1 and a load tap changer. A drive mechanism 8 that transmits to the switching device 1, a stepping mechanism 9 that transmits the rotation of the main drive shaft of the drive mechanism 8 through mechanical mechanisms such as gears and cams, an extreme stop mechanism 10, and the tap position and switching number. Indication mechanism 11 that displays etc.
, a motor power supply control circuit 12 that controls the power supply of the electric motor 7 , and a no-fuse breaker 13 provided in the power supply circuit of the electric motor 7 .

With the above configuration, when the load 3 of the power transmission and distribution system fluctuates, the on-load tap changer operation command generation circuit 5:
A tap switching signal is output to the electric operating mechanism 2 of the tap switching device under load. The motor power supply control circuit 12 of the electric operation mechanism 2 closes the power supply circuit of the motor in response to the tap switching signal, and rotates the motor 7.
When the on-load tap changer 1 completes tap switching, the stepping mechanism 9 switches the taps of the on-load tap changer transformer 6 by rotating a driving shaft (not shown) that drives the on-load tap changer 1 of the drive mechanism 8. A switch mechanism installed in the cam mechanism generates a tap change signal for the load tap changer 1, and outputs a motor stop signal to the motor power supply control circuit 12 of the motor 7. .

[Problems with background technology]

By the way, during the tap switching described above, the tap switching device 1 under load may cause tap congestion.
This tap congestion is caused by a failure in the power supply system of the electric motor 7, and it is also caused by the on-load tap changer 1 failing and the electric motor 7 driving the on-load tap changer 1 stopping during tap switching. There is.
In this way, if tap congestion occurs in the tap switching device under load, the conventional electric operating mechanism 2 does not have a detection element for the tap congestion, so if the tap switching device 1 breaks down and the electric motor 7 When a tap jam occurs that causes the motor to stop, a large current flows through the motor due to the excessive load. At this time, the no-fuse breaker 13 operates, but
This operation time takes several seconds. Therefore, the electric motor 7
The above-mentioned large current flowed for several seconds and there was a risk of damage.

[Purpose of the invention]

The present invention solves the problems of the above-mentioned prior art,
To provide a highly reliable on-load tap switching device which makes a judgment in a short time when the on-load tap switching device causes tap congestion and protects an electric motor that drives the tap switching device.

[Summary of the invention]

Therefore, the present invention determines tap congestion by monitoring the current or torque of the motor when current is being supplied to the motor, and when tap congestion occurs, opens the power supply circuit of the motor and It is characterized by displaying.

[Embodiments of the invention]

FIG. 2 is a block diagram showing the main parts of a load tap switching device according to an embodiment of the present invention. In the figure, the same reference numerals as those in FIG. A rotation detection unit 16 detects the rotation of the mechanical part by optical pulses or positional displacement, and 16 is an electric unit that converts the optical pulse detected by the rotation detection unit 15 or the amount of displacement of the position of a cam, etc., into an electrical signal pulse. A signal generation circuit 17 is an arithmetic control circuit that controls the motor power supply switching circuit 14 as a signal from the electric signal generation circuit 16 and a signal from the operating command generation circuit 5 of the on-load tap switching device. 19 is a display circuit that displays the tap number, switching frequency, abnormality, etc., which are the results of calculations in the calculation circuit 17; 20 is installed in the power supply circuit of the electric motor 7 and is connected to the calculation control circuit 17; This is a current detection circuit that outputs a signal.

With the above configuration, when the operating command generation circuit 5 for the on-load tap switching device outputs a switching operation command for the on-load tap switching device, the arithmetic control circuit 17 determines whether the command is a command to increase the tap voltage or a command to decrease the voltage. The forward rotation or reverse rotation circuit of the motor power supply switching circuit 14 is closed. Motor power switching circuit 1
4 closes, the electric motor 7 starts rotating. The rotation of the electric motor is detected by a rotation detecting section 15, and converted into an electric pulse signal corresponding to the rotation by an electric signal generating circuit 16. The arithmetic control circuit 17 counts pulse signals corresponding to the rotation speed of the electric motor 7. This counted value is compared with the set value required for one tap change stored in the memory circuit 18, and the motor power is switched in advance so that the motor 7 is at the normal stop position when the tap change of the load tap changer 1 is completed. Open circuit 14. When the motor power supply switching circuit 14 is opened, the motor stops and the one-tap switching ends.

Next, when tap congestion occurs in the on-load tap changer 1 such that the load on the electric motor 7 becomes excessive while the on-load tap changer is switching the taps,
The electric current is several times higher than normal tap switching.
flows to This current is detected by the current detection circuit 20, and if the value is greater than or equal to the set current value for determining abnormality stored in the memory circuit 18, the arithmetic control circuit 17 opens the motor power supply switching circuit 14 and brakes the motor 7. to stop it. Furthermore, the display circuit 19 displays that the tap changer 1 has caused a tap jam during load.

Furthermore, if a tap jam occurs in which the motor 7 does not rotate due to a failure in the motor power supply switching circuit 14 or the motor 7, no current is detected by the current detection circuit 20. The arithmetic control circuit 17 detects the current and outputs a tap traffic jam indication indicating a motor power supply system failure to the display circuit 19.

Therefore, according to this embodiment, when a tap traffic jam occurs in which a large current flows through the electric motor 7,
The motor power supply switching circuit 14 can be opened with a judgment of several milliseconds or less. This makes it possible to significantly shorten the determination time compared to the conventional no-fuse breaker, which takes several seconds to several tens of seconds, and prevents damage to the electric motor 7. . Furthermore, since it is possible to determine whether there is a failure in one tap changer system or a failure in the motor power supply system, an advantage is obtained in that the cause of tap congestion can be easily investigated.

FIG. 3 shows another embodiment of the present invention.
Reference numeral 1 denotes a torque detection circuit that detects the torque applied to the drive shaft of the drive mechanism of the electric motor 7 that drives the on-load tap changer 1. The output signal of the torque detection circuit 21 is input to the arithmetic control circuit 17.

If tap congestion occurs in the on-load tap switching device 1 while the on-load tap switching device is in the middle of switching taps, the torque applied to the drive shaft of the electric motor 7 will be several times or more when the taps are switched normally. This torque is detected by the torque detection circuit 21, and if the set torque value and set time for abnormality determination stored in the memory circuit 18 are greater than a certain value, the arithmetic control circuit 17 opens the motor power supply switching circuit 14, and the motor 7 and displays on the display circuit 19 that the on-load tap changer 1 has caused a tap jam.

Furthermore, when a tap jam occurs in which the motor 7 does not rotate due to a failure of the motor 7, the motor power supply switching circuit 14 does not detect torque from the torque detection circuit 21. The arithmetic control circuit 17 detects the torque and outputs a tap traffic jam indication indicating a motor power supply system failure to the display circuit 19.

Even when the on-load tap switching device is configured in this manner, the same effects as in the embodiment shown in FIG. 3 can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, most of the electric operation mechanism is composed of electric circuits, which eliminates malfunctions, and when tap congestion occurs, the power supply circuit of the electric motor immediately drives the tap changer. Since the tap opens, damage to the electric motor can be prevented during tap congestion, and a highly reliable tap switching device under load can be obtained. Furthermore, by detecting the tap congestion using the current or torque of the electric motor, it becomes possible to easily investigate the cause of the tap congestion.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional tap switching device under load, and FIGS. 2 and 3 are block diagrams of a tap switching device under load showing each embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Tap changer on load, 2...Electric operation mechanism, 7...Electric motor, 14...Motor power supply switching circuit, 15...Rotation detection unit, 17...Arithmetic control circuit, 18...Memory circuit, 19 ...display circuit, 20
... Current detection circuit, 21 ... Torque detection circuit.

Claims (1)

[Scope of Claims] 1. An electric motor that drives a load tap changer, a power supply switching circuit that switches between forward/reverse rotation and stop of the motor, a rotation detection circuit that detects the rotational state of the electric motor, and a rotation detection circuit that detects the rotational state of the electric motor. A current detection circuit that detects current; a storage circuit that stores switching data and drive sequence of the on-load tap changer; and a memory circuit that processes the signal output from the rotation detection circuit based on the drive sequence and switching data. , comprising an arithmetic control circuit that performs tap switching by controlling the power supply switching circuit, detects tap congestion by monitoring the output of the current detection circuit at the time of the tap switching, and opens the power supply switching circuit. An on-load tap switching device characterized by: 2. An electric motor that drives the on-load tap changer, a power supply switching circuit that switches the electric motor between forward and reverse rotation and stop, a rotation detection circuit that detects the rotational state of the electric motor, and a torque that detects the torque generated by the electric motor. Based on the detection circuit, the storage circuit that stores the switching data and drive sequence of the on-load tap changer, and the drive sequence and switching data,
Processing the signal output from the rotation detection circuit,
and an arithmetic control circuit that performs tap switching by controlling the power supply switching circuit, detects tap congestion by monitoring the output of the torque detection circuit at the time of the tap switching, and opens the power supply switching circuit. An on-load tap switching device characterized by: