JPS5860233A - Pressure monitoring device - Google Patents

Abstract

PURPOSE:To obtain the pressure monitoring device whose reliability in fault detection or prediction is higher, by monitoring the pressure (density) value as well as the temporal speed of change in the pressure (density) in a container. CONSTITUTION:When an arcing fault occurs and the internal pressure reaches a preset value PB, a switch SPB is actuated, and its contact signal is sent to a time counter circuit TM2 and to an alarm circuit AL. When the internal pressure is increased and reaches a preset point PC and a switch SPC is operated, a circuit TM2 stops the measurement of the elapse of time and sends a time signal DELTAt2, which represents the measured elapsed time, to a comparing circuit COM2. In the comparing circuit COM<2>, the signal DELTAt2 is compared with a reference value DELTAT2. When DELTAt2<DELTAT2 a locking signal is outputted, a corresponding breaker CB is operated through a trip circuit TR, and a faulty part is instantly isolated. When DELTAt2>DELTAT2, the fault is not serious, and it is judged that enough time is available for the action taken by the service personnel. Therefore only the alarm is indicated by an alarm circuit AL.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure monitoring device for a gas insulated switchgear.

The gas insulated switchgear is constructed by filling a metal container with 8F gas, which has high dielectric strength and excellent breaking ability, at a pressure of several atmospheres. The 8F gas filled inside the container is maintained at the rated pressure, and normally the pressure fluctuates slowly around the rated pressure due to the influence of outside temperature and leakage from airtight areas.

In such a gas insulated switchgear, a drop in pressure inside the container is conventionally monitored using a temperature compensated gas pressure switch or a gas density switch. An overview of the operations of these switches will be explained with reference to FIG. In FIG. 1, the vertical axis represents the pressure or density of the gas, and in order to compare and contrast the conventional operation with the operation of the present invention, which will be described in detail later, the left side of the vertical axis represents the prior art. In the left part of Figure 13, where the right part shows the product according to the present invention, the rated pressure (or density) P
As mentioned above, the gas sealed in N is accompanied by slow pressure fluctuations, and the alarm level is P.

When this level is reached, an alarm signal is output, and the lock level reaches 9!
Then, a lock signal is output and the offending device is disconnected from the system.

We already have over 70 years of operating experience in gas insulated switchgear.
In the meantime, it is possible to obtain extremely high reliability against gas leaks due to improvements in sealing technology.) On the other hand, rational design of this highly reliable equipment is required;
In addition to monitoring pressure drops due to gas leaks, there is a growing need for technological support for even higher reliability, such as accident detection and prediction.

This invention was made in view of the above points, and by monitoring the pressure (density) value inside the container and also monitoring the temporal speed of pressure (density) change, it is possible to improve the reliability of accident detection or prediction. This provides a high pressure monitoring device.

As mentioned above, when the equipment is in normal condition, the pressure increases rapidly on the order of a few milliseconds, and when a metal container or piping breaks, the pressure decreases over a similar period of time. As the pressure changes rapidly,
Monitoring the temporal rate of pressure change can provide even more reliable accident detection and prediction.

Referring again to FIG. 1, as shown on the right side thereof, the pressure monitoring device according to the present invention has an additional system for detecting the falling time Δt and rising time Δt2 between the U points of the pressure, Therefore, the pressure setting point for detecting the falling time is the alarm level P. , and in addition to the locking level PL, a pressure drop setting level PA is provided therebetween. Also, λ pressure rise setting levels P and P as pressure setting points for detecting the rise time. is provided.

The falling time Δt and rising time Δt2 detected by each pressure setting point are compared with the falling setting time ΔT and rising setting time ΔT1, respectively, set in advance, and an abnormal signal is output if each is smaller than the set time. .

FIG. 2 is a schematic configuration diagram showing an embodiment of the pressure monitoring device according to the present invention conceptually explained in FIG. and a pressure level detection switch group S is shown. These pressure level detection switch group S detects the pressure setting level shown in FIG. , the pressure switch SPB is the pressure set point P
B, and the pressure switch SPC is the pressure set point P.

Detect each. The time counter circuit TM receives signals from the switches S and SPo, and its A output is connected to the comparison circuit COM. Similarly, time counter circuit TM receives signals from switches SPB and SPc, and its output is connected to comparison circuit COM. The outputs of the comparison circuits COM and COMU are connected to a trip circuit TR, and the output of the trip circuit TR controls opening and closing of the circuit breaker CB.

Also, the alarm circuit AL has a switch SP. Or receive a signal from either SPB and display an alarm.

In the above configuration, when a flashover accident occurs and the internal pressure reaches the set value PB, the switch 8PB operates and sends the contact signal to the time counter circuit TMY and also to the alarm circuit A. The alarm circuit AL immediately displays an alarm, and when the time counter circuit TM receives the contact signal,
It turns on and starts measuring the elapsed time after receiving the contact signal.

After that, the internal pressure increases and continues to the pressure set point P. , and when the switch SPo is activated, the time counter circuit TM receives the contact signal and stops measuring the elapsed time, and transfers the time signal Ht representing the measured elapsed time to the comparison circuit CO.
Output to Myu. Comparison circuit COM.

Now, compare the signal △tU with the reference value △T, and get △tU〈
In the case of △T, a lock signal is output and the trip circuit TR
Then, the corresponding breaker CB is opened, and the faulty part is immediately removed from the system. △1. >ΔT, it can be determined that the failure is minor and there is sufficient time for the staff to take countermeasures, so only the alarm is displayed from the alarm circuit AL.

Similarly, for example, if there is a hole in the tank and the internal pressure suddenly drops, first, when the internal pressure reaches the set value Po, the switch SPo operates and sends the contact signal to the time counter circuit TM, and also to the alarm circuit. Send it to A as well. The alarm circuit AL immediately issues an alarm, and the time counter circuit TM is turned on upon receiving the contact signal and starts measuring the elapsed time since receiving the contact signal. Thereafter, the internal pressure decreases and reaches the pressure set point P, and when the switch SPA is activated, the time counter circuit TM receives the contact signal and stops measuring the elapsed time, and generates a time signal representing the measured elapsed time. △t,
The comparison circuit COM.

Output to. The comparator circuit COM compares the signal Δt7 with the reference value ΔT, and calculates Δ1. If <ΔT7, a locking signal is output, the corresponding breaker CB is opened via the trip circuit TR'tt, and the faulty part is immediately removed from the system. △1. >ΔT, it can be determined that the failure is minor and there is sufficient time for the section staff to take countermeasures, so only the alarm is displayed from the alarm circuit AL.

As described above, according to the present invention, in order to monitor malfunctions in equipment, not only pressure values but also temporal changes in pressure values are detected. It's becoming more sexual.

Furthermore, since the temporal speed of pressure change is compared with a reference value, it is possible to immediately determine whether repairs should be carried out quickly or whether the accident category needs to be isolated.

Furthermore, in this embodiment, the pressure drop setting level PA is set to a locking level P and an alarm level P, for example. Since it is set between △1. >ΔT7, even when the alarm output is the only one and no heavy industry locking signal, the equipment can be disconnected if necessary within the pressure drop time from pressure drop level jPA to locking pressure level 9. In this way, the device can be disconnected from the electrical circuit while its performance is guaranteed, improving the reliability of the system.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the conventional example on the left side and the present invention on the right side, so that the difference in operation between the conventional pressure monitoring device and the pressure monitoring device according to the present invention can be compared and contrasted;
The figure is a block diagram showing a pressure monitoring device according to an embodiment of the present invention. In the figure, / is a gas insulated switchgear, λ is a container, CB is a breaker, PN is a rated pressure, PL is a pressure drop locking level, and ri is a pressure level detection switch.
sP. is a pressure drop alarm level detection switch, sPA is a pressure drop setting level detection switch, SPB is a pressure rise alarm level detection switch, SPo is a pressure rise setting level detection switch, 1゛M and TM are time counter circuits, CO
M, and COM are comparison circuits, TR is a trip circuit,
AL is an alarm circuit. Agent Shin Kuzuno −

Claims (1)

[Claims] In a pressure monitoring device in which a switch for detecting gas pressure or density is provided inside a container of a gas insulated switchgear, and an alarm is issued by a contact signal of the switch, a first pressure setting value that should issue an alarm. a first level detection switch for detecting a first pressure set value; and a first level detection switch for detecting a first pressure set value; and a first level detection switch for detecting a first pressure set value; A contact signal from the level detection switch starts the operation to measure the elapsed time from that point, and when the internal pressure of the container reaches the first pressure setting value, a contact signal is sent from the first level detection switch. a time counter circuit that stops the operation of measuring the time U and outputs the measured time signal; and a time counter circuit that compares the time signal with a reference time value and determines that the time value represented by the time signal is less than the reference time value. A pressure monitoring device comprising: a comparison circuit that outputs a locking signal for disconnecting a corresponding faulty circuit when the pressure is small.