JPH027829A - Monitor device of gas insulation type electrical equipment - Google Patents

Abstract

PURPOSE:To monitor droppage of gas density or abnormal gas pressure increase by setting a temperature increase value as an initial value based on the variation of gas pressure during initial power supply. CONSTITUTION:Upon occurrence of gas leak in a gas partition chamber 1, gas density or thermal capacity drops. When the gas pressure Pn in the gas partition chamber 1 variable with time elapsed after start of power supply and the outer air temperature Ta are recorded, the gas temperature increase T0 due to power supply can be operated according to formula I and the operated gas temperature rise T0 is set as an initial value. The gas temperature increase Tn for the current In can be operated through formula II based on the initial value. Tn operated based on the outer air temperature and current during operation of a gas insulation type electrical equipment is added to an outer air temperature Ta to obtain a gas temperature Tn+Ta. Since the gas density can be obtained based on the gas temperature, the gas density can be monitored with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a monitoring device for gas-insulated electric equipment such as a gas-insulated switchgear.

(Prior Art) A conventional gas insulated switchgear is shown in FIG. 6. In the figure, 30 is a circuit breaker, 31 is a linear disconnector, 32 is a line grounding device, 33 is a cable connection device, and 34 is a Cable split through type current transformer, 35 is a bus bar, 36 is a grounding device for inspection,
37 is a right-angled cross-section disconnector, and 38 is a conductor (live part).

The three-phase conductor 38 is insulated and supported by an insulating spacer 39, housed in a metal container, and SF with diffused pressure inside.
, the gas is sealed. SF, gas acts as an insulating and arc-quenching medium. In addition, the insulating spacer 39 not only supports the conductor 38 but also divides the inside of the container into each element to form a plurality of independent gas compartments, so that filling and exhausting of SF and gas is performed only in the necessary parts. It's there.

As a result, high insulation performance can be obtained with small insulation dimensions, and when compared with conventional equipment, the volume and installation area of the equipment can be significantly reduced, and moreover, it becomes highly reliable.

In this gas insulated switchgear, it is necessary to monitor the gas pressure drop due to leakage of the sealed gas (S F h gas) in the gas compartment or the gas pressure rise due to abnormal overheating. As a monitoring device for this purpose, as shown in FIG. 5, a gas pipe 41 for filling and exhausting gas is installed in the gas compartment 1, and a gas pipe 41 for detecting abnormalities in gas pressure is installed in the middle of this pipe 41. A pressure inch 43 is provided.

At this time, even if the gas density is constant, the gas pressure changes due to changes in gas temperature that follow changes in outside air temperature.
The pressure switch 43 does not operate when the temperature of the reference gas in the temperature sensor 44 and the temperature in the gas compartment 1 are in balance, and the pressure switch 43 does not operate when the temperature of the reference gas in the temperature sensor 44 and the temperature in the gas compartment 1 are in balance, and if the gas density decreases due to gas leakage in the gas compartment 1, etc. It is designed to operate when the pressure balance reaches a certain level. In addition, in Fig. 5,
45 is an on-off valve, and 46 is a gas charging/discharging port.

[Problem to be solved by the invention]

Although the gas in the gas compartment 1 is heated to a temperature higher than the outside temperature by energizing the internal conductor 38, the reference gas in the temperature sensing portion 44 of the pressure switch 43 is at approximately the same temperature as the outside temperature.

Therefore, the operating pressure of the pressure switch 43 is not constant depending on the magnitude of the current flowing to the conductor 38 in the gas compartment chamber 1.
There was a problem in that an error occurred between this and the true gas density in the gas compartment 1.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a monitoring device for gas-insulated electric equipment that detects the gas density in a gas compartment with a value with little error and monitors a decrease in gas density or an abnormal increase in gas pressure. It is.

[Means to solve the problem]

The monitoring device for gas-insulated electrical equipment of the present invention includes a pressure gauge that measures the pressure in the gas compartment, an ammeter that measures the current flowing through the conductor in the gas compartment, and an ammeter that measures the outside air temperature around the gas compartment. A current is applied to the conductor while being measured by the ammeter. The gas temperature rise value ΔTo in the gas compartment when electricity is applied is calculated by equation (1), and P, 1-P.

ΔT, --T, ... (1) P7: Gas pressure in the gas compartment when the current is energized Po: Gas pressure in the gas compartment measured by the squid meter before energization T,: 0 to the outside temperature measured by the thermometer:
Constant Calculate the gas temperature rise value ΔT7 in the gas compartment when the conductor is energized with t'tRI− according to the measured value of the ammeter using equation (2), α: constant From this, the gas temperature ΔT in the gas compartment, , +T, and calculate the gas density.

[Effect]

According to this invention, T0 is set as an initial value for changing the gas temperature rise value from the gas pressure change during initial energization, and the gas temperature rise value ΔT,1 is calculated from this and the energization current value during subsequent operation, From this and the outside air temperature T, the gas temperatures ΔT and +T in the gas compartment are calculated. Therefore, the gas temperature, which is affected by the current flowing to the conductor inside the gas compartment, can be accurately detected, so the gas density inside the gas compartment can be detected with a value with little error, and the gas density can be detected as low or abnormal. The increase in gas pressure can be monitored with high precision.

(Example) Fig. 1 shows a monitoring device for gas-insulated electric equipment according to this embodiment. It is divided to form a gas compartment 1. This gas compartment 1 is filled with SF and gas.

A pipe 6 having SF and gas filling/exhaust ports 5 is attached to the gas compartment 1, and a pressure sensor 8 is provided between the on-off valves 7, 7 of the pipe 6.

In addition to this pressure sensor 8, there is also a thermometer (temperature sensor, etc., not shown) for measuring the outside air temperature around the gas compartment l, and a pressure gauge for measuring the pressure inside the gas compartment 1. , and an ammeter (not shown) for measuring the current flowing through the conductor in the gas compartment 1. Next, the operating procedure of this monitoring device will be explained.

When the gas density in the gas compartment 1 is constant, the gas temperature T and the gas pressure P0 have a linear relationship, as shown by the straight line A in FIG. Let the characteristics be expressed by the following equation.

Pa = ko X”l”+p0 From this, the gas temperature T is expressed by the following equation.

T= (po −Po)/ka If there is a gas leak in the gas compartment l,
Since the gas density decreases and the heat capacity decreases, the relationship between gas pressure and temperature is as shown by straight line B.

Gas compartment 1 changes over time after energization starts
By recording the internal gas pressure P7 and the outside air temperature T, the gas temperature increase value ΔTo due to current application can be calculated using the following equation.

ΔT, -T-T.

-(P-po)/ka T, ... (1) This Δ
T, is set as the initial value. The characteristics of ΔTo at this time with respect to elapsed time are shown in FIG.

Based on this initial value, the gas temperature rise value ΔT when the current is 7 is 臥ΔT, l - ΔT6 X (T, 1/Io)...
It is possible to calculate from (2) (α is mentioned above). The α value is determined from the design data of the device. FIG. 3 also shows the characteristics with respect to the elapsed time when ΔT.

In this way, ΔT calculated from the measured value of the outside air temperature and the measured value of the energizing current during operation of the gas-insulated electrical equipment,
, and the outside air temperature T, the gas temperature ΔT, +T can be calculated. Therefore, from this gas temperature, for example, the Pittie-Bringeman gas state equation (Beattie
Since the gas density can be determined using the Bridgeman formula, the gas density can be monitored with high accuracy.

〔Effect of the invention〕

According to this invention, by setting the gas temperature rise value ΔTo as an initial value from the gas pressure change at the time of initial energization,
Since the gas temperature in the gas compartment can be calculated from the energization 1a flow value during operation and the outside air temperature, the gas density in the gas compartment can be detected with high accuracy to prevent a decrease in gas density or abnormal gas pressure. The rise can be accurately monitored.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the present invention, Fig. 2 is a graph showing the relationship between gas pressure and temperature in the gas compartment, and Fig. 3 is a graph showing the relationship between the elapsed time in the energized state and the gas temperature rise value. A graph showing the relationship, FIG. 4 is a sectional view of a conventional gas insulated switchgear, and FIG. 5 is a schematic diagram of a conventional monitoring device. 1--Gas compartment, 4--Insulating spacer, 8-Pressure sensor

Claims (1)

[Claims] A pressure gauge that measures the pressure in the gas compartment, an ammeter that measures the current flowing through a conductor in the gas compartment, a thermometer that measures the outside air temperature around the gas compartment, and an arithmetic device. and the gas temperature rise value ΔT_o in the gas compartment when a current I_o is applied to the conductor while being measured by the ammeter is expressed by equation (1).
Calculated by ΔT_o=(P_n-P_o)/(K_o)-T_a...
(1) P_n: Gas pressure in the gas compartment when current I_o is applied P_o: Gas pressure in the gas compartment measured by the pressure gauge before energization T_a: Outside air temperature measured by the thermometer K_o: Constant The ammeter The current I in the conductor according to the measured value of
Gas temperature rise value Δ in the gas compartment when _n is energized
T_n is calculated by equation (2), ΔT_n=ΔT_o(I_n/I_o)^α...(2) α: constant From this, the gas temperature ΔT_n+T_a in the gas compartment is calculated, and the gas density is determined. Equipment monitoring device.