JPH02264313A - Runaway detecting device for automatic voltage regulating relay - Google Patents

Abstract

PURPOSE:To prevent useless tap change and the variation of system voltage due to it by detecting the runaway of the tap change by the combination of time lag relays. CONSTITUTION:In the case where an AVR operates normally, since the time lag relay 2 operates before an AVR output contact 4a having been closed once is closed again, the self-holding of an auxiliary relay 1 is released by the contact 2b, and an output relay 3 never operates. The output relay 3 operates after leaving some time delay in order to avoid lap time for the contact 2a2 to operate and for the contact 1a to return. Next, in the case where the AVR becomes out of order, and the output contact 4a operates before the operating time limit of the time lag relay 2, since the auxiliary relay 1 does not return even if the time lag relay 2 operates, the relay 3 operates through the route of 2a2-1a-3, and an alarm is indicated for an external part, and tap changing operation is locked.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a runaway detection device for an automatic voltage regulating relay (hereinafter referred to as AVR).

(Prior Art) Integral operation type AVII is generally used for voltage control of on-load tap change transformers and the like. This relay inputs the main circuit voltage to be controlled via a potential transformer (PT), integrates the difference with a predetermined set voltage over time using an integrating circuit, and outputs it after a certain time. Furthermore, this output operates a tap changer such as a transformer to control the main circuit voltage.

^VR's integration circuit is generally reset by the start of tap switching, and repeats the operation of starting the integration operation anew after the switching is completed.

Figure 2 shows a general ^VH circuit. Instrument transformer 2
The main circuit voltage is input to ^VR3 via.

In ^vR, it is converted to a DC voltage through an AC/DC conversion circuit 4, and compared with a reference value given by a reference voltage setting adjustment resistor 5 by a subtracter 6 to obtain a deviation voltage.

This deviation voltage is time-integrated by an integrator 7, and when it reaches a certain value, the output relay 11 is operated and outputted to the outside through the contact 11a.

This contact 11a provides an operation signal to a tap switching operation mechanism such as a transformer. Further, when the switching starts, the integrator is reset by the reset contact 8, and when the switching is completed, the contact is opened to start the integration operation again, and the above-mentioned operation is repeated.

Here, an adjustment resistor is used as the 1g adjustment resistor for setting the reference voltage, and the reference voltage is set to a required reference voltage.

Furthermore, a program control method is also commonly used in which only this reference voltage setting section is taken out to the outside, and several reference voltage setting values are selected over time to change the reference voltage. In this case, there are many moving parts such as a single adjustment resistor, a selection switch part, external wiring, and electrical contact parts, and there is a high possibility that a contact failure or the like will occur.

On the other hand, since the reference voltage setting corresponds to a change in resistance value and is used in a low voltage circuit, the contact resistance value may cause an error, and in the worst case, it may become infinite in the case of an open state.

Fig. 3 shows an example of a circuit when an adjustment resistor for setting the reference voltage is placed externally. One point is closed and provides the reference voltage setting value to AVH.

(Problems to be Solved by the Invention) As mentioned above, when the reference voltage setting adjustment resistor is placed externally for program control, the adjustment resistor main body sliding part, selection contact part, external wiring Poor contact at the connection parts, etc. is likely to occur (This may cause malfunctions in the operation of the AVH, and in turn, there are cases where the taps of the transformer, etc. are switched more than necessary, causing an abnormality in the system voltage. In other words, poor contact at the selection contact This causes abnormal operation of the AVR, resulting in adverse effects such as a drop in system voltage due to tap runaway.

The present invention is intended to prevent the above-mentioned problems, and
The operating status of the R output is constantly monitored, and if the AVH operates at a cycle shorter than the normally expected operating time, it will be detected, displayed and alarmed, and the tap switching operation will be locked to prevent switching operations due to malfunctions. It is an object of the present invention to provide a runaway detection device for an automatic voltage regulator that prevents runaway.

(Left below) [Structure of the Invention] (Means for Solving the Problems) In the present invention, in an automatic voltage regulating relay that controls the voltage of a tag switching transformer on load, the operating state of the output contact of the automatic voltage regulating relay is controlled. an auxiliary relay to detect, a first time limit relay to detect that the operation of the output contact is in a normal operating state, and a second time limit relay to determine whether there is an abnormal operation of the output contact from a comparison of the operations of each of the relays. and a relay, and is configured to detect tap runaway when the output contact repeatedly outputs in a short period of time.

(Function) If the output contact of the automatic voltage regulating relay is operating normally, the self-holding contact of the auxiliary relay is released by the first time-delay relay, so that the second time-delay occurs before the output contact closes again. The relay will not operate, but if the output contact operates before the operating time limit of the first time-limited relay, the auxiliary relay will not recover, so the second time-limited relay will operate and display/display.
Alert.

(Example) Examples will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a monitoring circuit according to the invention.

As shown in FIG. 1, the output contact 4a of the AVH is connected in series with the auxiliary relay 1, and when the output contact 4a of the AVR is closed, the auxiliary relay 1 is energized and self-maintained. Contact 1a of auxiliary relay 1 is connected to time limit relay 2.
and the lock contact 5b of AVH are connected in series, and
The contact 2a of the time limit relay 2 is connected in parallel to the lock contact 5b of the VR, and these are connected between the control power source. Therefore, upon completion of tap switching, the AVR reset contact 5b
When it returns (closes), the time limit relay 2 is energized because the 1a contact is already closed. The operation time of the time-limited relay 2 is set to be less than the operation time normally assumed for the above-mentioned AVR. In addition, the time limit relay 3 has an auxiliary relay °1
The contact 1a of the time limit relay 2 and the time limit contact 2a2 of the time limit relay 2 are connected in series, and these are connected between the control power sources.

Next, I will explain the effect.

If the AVR is operating normally, the time-limiting relay 2 is activated before the AVR output contact 4a, which was previously closed, is closed again.
operates, the self-holding of the auxiliary relay 1 is released by the contact 2b, and the output relay 3 does not operate. The output relay 3 operates with a slight time limit in order to escape the lap time from when the contact 2a2 operates to when the contact 1a returns.

Next, if the AVR becomes malfunctioning and the output contact 4a operates before the operation time limit of the time limit relay 2, the auxiliary relay 1 will not return even if the time limit relay 2 operates, so 2a2-1
The output relay 3 operates on the path a-3, displays and warns the outside, and further locks the tap switching operation.

[Effects of the Invention] As explained above, according to the present invention, runaway due to poor contact in the reference voltage section of the AVH can be detected with just one tap operation, and unnecessary tap switching or the runaway caused by this can be detected. Fluctuations in grid voltage can be prevented. Moreover, since it is an independent circuit, it can be easily added to a conventional circuit, and is particularly effective in application to a control device that is used for a long time (and therefore has a high probability of failure).

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of a runaway detection circuit for an automatic voltage regulating relay according to the present invention, and FIG. 2 is an explanatory diagram of an AVR circuit.
FIG. 3 is an explanatory diagram of the ^vn circuit with added program control.

Claims (1)

[Claims] In an automatic voltage regulating relay that controls the voltage of a tap-changing transformer on load, an auxiliary relay that detects the operating state of an output contact of the automatic voltage regulating relay and detects that the operation of the output contact is in a normal operating state. and a second time-limited relay that determines whether or not there is an abnormal operation of the output contact based on a comparison of the operations of each of the relays. A runaway detection device for an automatic voltage regulating relay, which detects as follows.