JPH0729463A - Protective relay device for oil fill transformer - Google Patents

Abstract

PURPOSE:To prevent the wrong operation of a protective relay device for oil filled transformer by a shock such as a earthquake. CONSTITUTION:When a transformer is broken to change the flow of oil, the oil is carried from the transformer in the direction of a conservator. The change of the flow rate is detected by an ultrasonic flow rate detector 7. When a gas is generated by this failure on the other hand, the gas is stored in a gas basin 6, and the gas pressure is raised. When a gas vent valve 2 is worked by this gas pressure, contacts 5, 4 are closed, and a signal is transmitted to a control part 1. The control part 1 operates a circuit breaker according to the signal from the ultrasonic flow rate detector 7 and the signal for gas pressure from the contacts 5, 4 to interrupt, for example, the input current of the transformer.

Description

Detailed Description of the Invention

[0001]

This invention relates to an oil-filled transformer,
In particular, the present invention relates to a protective relay device for an oil-filled transformer that detects a transformer failure and protects the transformer.

[0002]

2. Description of the Related Art An example of a conventional oil-immersed transformer protective relay for protecting a transformer is shown in FIG. FIG. 7 shows a vertical sectional view of the Bookholtz relay described on page 140 of “Handbook of Electric Power Equipment” (published by Ohmsha, Ltd., April 30, 1963). In FIG. 7, 43 and 44 are floats which are operated by the jet of oil caused by the accident of the transformer or operated by the ups and downs caused by the generation of gas by the accident. 45, 46, 47,
Reference numeral 49 is a contact point and is connected to an external circuit via a signal line (dotted line). The contact 49 is attached to the float 43, the contact 47 is provided at a position in contact with the contact 49, the contact 46 is attached to the float 44, and the contact 45 is the contact 46.
It is provided at the position where it comes into contact with. Reference numeral 42 denotes a support shaft for the float 43. When gas is generated due to a transformer failure, the float floats up and down around this support shaft, and the contact 49 and the contact 47 come into contact with each other to close the external circuit. As a result, an alarm signal is output to the outside, or a shutoff signal for shutting off the circuit breaker is output. Reference numeral 41 is a support shaft of the float 44, and the float 4
4 moves around this support shaft 41. Then, when an oil jet is generated due to a transformer accident, the floating member 44 causes the support shaft 4 to move.
It moves in the direction of the conservator around 4 and closes the contacts 45 and 46. As a result, an alarm signal and a cutoff signal are output to the outside. This conventional Bookholtz relay is provided in the connecting pipe between the transformer body and the conservator.
It should be noted that this conservator serves to prevent a pressure difference caused by a change in the volume of oil that changes depending on the ambient temperature and the load condition.

Next, the operation of this conventional example will be described. When the transformer fails for some reason, a jet of oil is generated due to the abrupt heat generated by the transformer. This jet flows from the transformer in the direction of the conservator, so that the float 44 moves and closes the contacts 45, 46, and issues an alarm to the external circuit. At this time, a large amount of gas is also generated, and this gas accumulates in the accommodating portion of the float 43. Then, the contacts 49 and 47 of the float 43 are closed and an alarm signal is generated in the external circuit. As a result, this alarm signal rings the bell or breaks the circuit breaker.

[0004]

Since the conventional Bookholtz relay is constructed as described above, it often malfunctions due to movement of oil due to an impact such as an earthquake, and the reliability is not so high. There is a point.

The present invention has been made in order to solve the above problems, and it is possible to obtain a protective relay for an oil-filled transformer which prevents malfunction due to shock such as an earthquake and has high reliability for the system. Is intended.

[0006]

As shown in FIG. 1, a protective relay device for an oil-filled transformer according to the first aspect of the present invention, when a transformer fails, the flow rate of oil due to this failure is changed to ultrasonic waves. Flow rate detector (ultrasonic type flow rate detector 7)
And a gas pressure detector (contacts 4, 5 etc.) that has a gas vent valve 2 that opens when the generated gas pressure of the gas exceeds a predetermined value and that outputs a signal when the gas vent valve is opened. And a control unit 1 that outputs a relay signal based on the signal from the flow rate detector and the signal from the gas pressure detector.

As shown in FIG. 3, the protective relay device for an oil-filled transformer according to the second aspect of the present invention, as shown in FIG. 3, when the transformer for adjusting the volume fluctuation of the oil fails, the oil Of the first flow rate detector (ultrasonic type flow rate detector 7) for detecting the flow rate of the oil based on the ultrasonic wave, and the oil communication pipe connecting the transformer and the conservator to change the flow rate of the oil. And a second flow rate detector (differential pressure detector) that generates a pressure signal corresponding to the pressure difference when oil passes through the pressure difference generating means (orifice 10). 11) and a controller 20 that outputs a relay signal based on the signals from the first and second flow rate detectors.

As shown in FIG. 5, a protective relay device for an oil-filled transformer according to the third aspect of the present invention, when a failure occurs in the transformer, is based on a change in oil flow rate and the generated gas due to the failure. A flow rate detector (ultrasonic type flow rate detector 7) that detects the flow rate of the oil based on ultrasonic waves; and a gas detector 13 that outputs a signal corresponding to the type of the generated gas.
The controller 30 outputs a relay signal based on the signal from the flow rate detector and the signal from the gas detector.

[0009]

In the protective relay device for an oil-filled transformer according to the first aspect of the present invention, when the transformer fails, the flow rate of oil changes, and gas is generated, the flow rate detector (ultrasonic type flow rate detection) is first used. The device 7) detects the flow rate of the oil based on ultrasonic waves. Next, when the gas pressure of the generated gas exceeds a predetermined value and the gas vent valve 2 is opened, the gas pressure detector (contacts 4, 5 etc.) outputs a signal. The control unit 1 outputs a relay signal based on the signal from the flow rate detector and the signal from the gas pressure detector. Then, the relay signal is used to display the failure of the transformer or to open the breaker.

In the oil-filled transformer protective relay device according to the second aspect of the present invention, when the transformer fails and the oil flow rate changes,
First, the first flow rate detector (ultrasonic type flow rate detector 7) detects the flow rate of the oil based on the ultrasonic waves. on the other hand,
The pressure difference generation means (orifice 10) provided in the oil communication pipe connecting the transformer and the conservator generates a pressure difference from the change in the oil flow rate. Next, the second flow rate detector (differential pressure detector 11) generates a pressure signal corresponding to the above pressure difference when the oil passes through this pressure difference generating means. Next, the control unit 20 outputs a relay signal based on the signals from the first and second flow rate detectors.

In the protective relay device for an oil-filled transformer according to the third aspect of the present invention, when the transformer fails and the oil flow rate changes, the flow rate detector (ultrasonic flow rate detector 7) first causes The flow rate of the oil is detected based on ultrasonic waves. next,
The gas detector 13 outputs a signal corresponding to the type of the generated gas. The control unit 20 outputs a relay signal based on the signal from the flow rate detector and the signal from the gas detector.

[0012]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows an embodiment (embodiment 1) of the first invention.
2 is a longitudinal sectional view of a flow rate of the oil-filled transformer and a gas detecting portion, and FIG. 2 is a circuit block diagram showing an example of an internal circuit of the control unit of FIG. In FIG. 1, 2 is a gas vent valve, which is provided in a connecting pipe between the transformer and the conservator. A gas 6a is generated in the oil 6b due to a transformer accident and accumulates in the gas reservoir 6, and when the pressure exceeds a predetermined gas pressure, the lid 3 of the gas vent valve 2 opens (dotted line) and the gas is released. 4,5
Is a contact, the contact 4 is attached to the lid 3 of the gas vent valve 2, and the contact 5 is the contact 4 when the lid is opened by gas.
It is installed at the position where it comes into contact with. The gas vent valve 2, the lid 3, and the contacts 4 and 5 constitute a gas pressure detector that generates a signal when the gas pressure exceeds a predetermined value. An ultrasonic flow rate detector 7 detects the flow rate by ultrasonic waves, detects the flow rate of oil from the transformer to the conservator, and outputs a signal (voltage) proportional to this flow rate. The flow rate detector 7 is a liquid with a relatively clean oil, a low viscosity viscous void-free liquid in a vapor, and operates most efficiently when the amount of solid substances and gas bubbles is 1% or less by volume. To do. Further, the operation is uncertain when the gas phase of oil is 1 to 10%, and hardly operates when the gas phase is 10% or more. Therefore, it is installed between the gas reservoir 6 and the conservator. Reference numeral 1 denotes a control unit, which outputs a signal for shutting off the circuit breaker or a signal for displaying an alarm based on a signal from the contacts 4 and 5 due to gas pressure and a signal from the ultrasonic flow rate detector 7.

The control unit 1 has a structure as shown in FIG. 2, for example. In FIG. 2, 1a is a filter, 1b is a comparator, 1c is a timer, 1f is a set value, 1d is an AND circuit, and 1e is a circuit breaker open signal generation circuit. Filter 1a
Inputs a contact signal due to contact between the contact 4 and the contact 5 of the gas vent valve 2 and outputs this signal to the AND circuit 1d. At this time, the filter 1a removes noise from the signal so that noise due to chattering of the contacts is not output. The comparator 1b compares the analog signal of the flow rate proportional to the flow rate from the ultrasonic flow rate detector 7 with a predetermined set value 1f, and outputs a signal when the signal of the flow rate is larger than the set value. The timer 1c is activated by the output signal from the comparator 1b and outputs a signal to the AND circuit 1d after a predetermined timer value.
The AND circuit 1d outputs a signal to the circuit breaker open signal generation circuit based on the signal from the filter 1a and the signal from the timer 1c, and the circuit breaker open signal generation circuit 1e is illustrated based on the signal. No Outputs a break signal to the breaker.

Next, the operation of the apparatus according to the first embodiment will be described. In Figure 1, when an accident occurs in the transformer,
Oil flows from the transformer to the conservator, and the flow rate changes greatly. The ultrasonic flow rate detector 7 detects the change in the flow rate with ultrasonic waves and outputs the change to the control unit 1. On the other hand, due to this accident, the gas 6a is generated and accumulated in the gas reservoir 6, and when the gas pressure exceeds a predetermined value, the gas vent valve 2 opens the lid 3. At this time, the contacts 4 and 5 are closed, and a signal is output to the control unit 1. In FIG. 2, the control unit 1 includes an AND circuit 1
d operates the circuit breaker open signal generating circuit 1e based on the gas pressure contact signal from the contact point 4 and the contact point 5 from the filter 1a and the flow rate signals from the comparator 1b and the timer 1c. Then, the circuit breaker open signal is output from the control unit 1.

FIG. 3 is a longitudinal sectional view of a flow rate detecting portion of an oil-filled transformer showing an embodiment (embodiment 2) of the second invention, and FIG. 4 shows an internal circuit of the control unit 20 of FIG. It is a circuit block diagram which shows an example. In the above-mentioned first embodiment, the accident of the transformer is detected from the gas and the flow rate, but in the device of the second embodiment, the accident of the transformer is detected only from the flow rate.
In FIG. 3, 8 is a conservator for adjusting the volume fluctuation of oil, 12 is a gas reservoir, and the ultrasonic flow rate detector 7 as the first flow rate detector for detecting the flow rate from ultrasonic waves is the same as that of the first embodiment. Are the same. Reference numeral 10 denotes an orifice, which is provided in a connecting pipe of oil 8a connecting the transformer and the conservator. The orifice 10 has a cylindrical shape having a certain thickness, and is fixed in contact with the outer peripheral surface of the cylindrical shape or the inner peripheral surface of the connecting pipe without any gap. A part of the connecting pipe is narrowed by the orifice 10, so that a pressure difference occurs in the oil flowing through the connecting pipe. Reference numeral 11 denotes a differential pressure detector as a second flow rate detecting means, which detects a pressure difference of oil before and after the orifice 10 and sends it to the controller 20. FIG. 4 shows the control unit 20.
2 is an internal circuit of FIG. 2, and another circuit of the same configuration including the comparator 1b, the set value 1f, and the timer 1c of FIG. 2 is provided (comparator 1b ', set value 1f', timer 1c). 1c '). The control unit 20 compares the signal from the differential pressure detector 11 with the comparator 1b ', and outputs the signal when the set value is 1f' or more. The operation is the same as that described in FIG. At the time of a transformer accident, the control unit 20 outputs a cutoff signal to the circuit breaker based on the flow rate signal from the ultrasonic flow rate detector 7 and the flow rate signal from the differential pressure detector 11.

FIG. 5 is a longitudinal sectional view of a flow rate detecting portion of an oil-filled transformer showing one embodiment (third embodiment) of the third invention, and FIG. 6 shows an internal circuit of the control unit 30 of FIG. It is a circuit block diagram which shows an example. For the internal components,
The same as in FIG. 2 (Embodiment 1), but the input signal is different. In FIG. 5, 12 is a gas reservoir, 13 is a gas detector, and the gas detector 13 outputs signals with different pulse widths depending on the type of gas. The signal from the gas detector 13 passes through the filter 1h in the control unit 30 (FIG. 2), but if the pulse width is small at this time, it does not pass through the filter 1h, and only a signal with a certain pulse width passes through the filter. pass. Therefore, when the gas detected by the gas detector 13 is a gas due to an electrical failure of the transformer,
By allowing the signal to pass through the filter, the control unit 30 outputs the circuit breaker signal based on the signal of the flow rate of the oil 8a and the signal of the gas type.

[0017]

As described above, according to the first aspect of the present invention, when the transformer fails and the oil flow rate changes and gas is generated, the flow rate change is detected by the flow rate detector. Since the gas is detected by the gas pressure detector and the relay signal is output based on these detection signals, there is an effect that malfunction due to shock such as an earthquake can be prevented. According to the second aspect of the present invention, when the transformer fails and the oil flow rate changes, the change in the oil flow rate is detected by the first flow rate detector based on ultrasonic waves, and the pressure of the flow rate is detected. The second flow rate detector detects the difference based on the difference, and the relay signal is output based on these detection signals. Therefore, in addition to the effect of the first invention, the failure can be detected with higher accuracy. There is an effect that can be. According to the third aspect of the present invention, when the transformer fails and the oil flow rate changes and gas is generated, the change in the flow rate is detected by the ultrasonic type flow rate detector, and the type of gas is changed. Since it is configured to output the relay signal based on the detection signal of the flow rate and the detection signal of the gas detected by the gas detector, in addition to the effect of the first invention, the type of accident of the transformer is known. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a flow rate and gas detection portion of an oil-filled transformer showing an embodiment of the first invention.

FIG. 2 is a circuit block diagram showing an example of an internal circuit of a control unit in FIG.

FIG. 3 is a longitudinal sectional view of a flow rate detecting portion of an oil-filled transformer showing an embodiment of the second invention.

4 is a circuit block diagram showing an example of an internal circuit of a control unit in FIG.

FIG. 5 is a vertical sectional view of a flow rate detecting portion of an oil-filled transformer showing an embodiment of the third invention.

6 is a circuit block diagram showing an example of an internal circuit of a control unit in FIG.

FIG. 7 is a vertical cross-sectional view of a flow rate and gas detection portion of an oil-filled transformer showing a conventional oil-filled transformer protective relay device.

[Explanation of symbols]

 1,20,30 Control unit 2 Gas vent valve 3 Lid 4,5,45,46,47,49 Contact 6,12 Gas reservoir 7 Ultrasonic flow rate detector 8 Conservator 9 Communication pipe 10 Orifice 11 Differential pressure detector 13 Gas detector 14 and 15 Float 41 and 42 Support shaft

Claims (3)

[Claims] 1. A protective relay device for an oil-filled transformer that outputs a relay signal based on a change in oil flow rate and a generated gas when the transformer fails, and the oil flow rate exceeds A gas pressure detector that has a flow rate detector that detects based on sound waves and a gas vent valve that opens when the gas pressure of the generated gas exceeds a specified value, and that outputs a signal when this gas vent valve is opened. A protective relay device for an oil-filled transformer, comprising: a relay unit; and a control unit that outputs a relay signal based on a signal from the flow rate detector and a signal from the gas pressure detector. 2. A protective relay device for an oil-immersed transformer that outputs a relay signal when a failure occurs in a transformer that adjusts oil volume fluctuations by a conservator, wherein the oil flow rate is based on ultrasonic waves. And a first flow rate detector for detecting the pressure difference, and a pressure difference generation means for generating a pressure difference due to a change in the flow rate of the oil, which is provided in an oil communication pipe connecting the transformer and the conservator, and the pressure difference generation means. A second flow detector for producing a pressure signal corresponding to the pressure difference when the oil passes through the means;
A protective relay device for an oil-filled transformer, comprising: a control unit that outputs a relay signal based on signals from the first and second flow rate detectors. 3. A protective relay device for an oil-filled transformer that outputs a relay signal based on a change in oil flow rate and gas generated when a failure occurs in the transformer. A flow rate detector that detects
A gas detector that outputs a signal corresponding to the type of the generated gas, and a control unit that outputs a relay signal based on the signal from the flow rate detector and the signal from the gas detector are provided. A protective relay device for oil-filled transformers.