JPH05180700A - Temperature measuring device - Google Patents

Abstract

PURPOSE:To reduce the switching number of the contact points of relays, lengthen a contact point life and heighten the reliability of a temperature measuring device in regard to the device for successively switching the contact points of relays and measuring the temperature of each temperature detection part in accordance with time division in order to measure the temperature of a plurality thereof. CONSTITUTION:A switch device 2 for cyclically switching contact points Ry1-Ry3 is provided, and an allowable temperature setting device 24 for previously determining to set the allowable temperature of a temperature measuring part to be measured in the switch device 2 and a minimum level holding circuit 26 for fetching and holding a temperature detection signal nearest to an allowable temperature set value in a cycle of switching of the contact points or a specified cycle thereof are set. In the case where the detection signal of the minimum level holding circuit 26 has a difference, compared with the allowable temperature, switching time intervals are shortened only when time intervals for switching the contact points R, of the relays RY are lengthened or the detection signal approaches the allowable temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring device, and more particularly to a measuring device suitable for constantly measuring the temperature of a large number of conductor portions such as semiconductors, transformers or disconnecting switches, to which main circuit voltage is applied. Regarding

[0002]

2. Description of the Related Art The temperature of a semiconductor device, a transformer, or a disconnector or a circuit breaker having a contact portion is constantly monitored to prevent accidents due to equipment failure or abnormal heating. In this case, temperature detection sensors such as thermistors are directly provided on a large number of conductor portions to measure the temperature of each portion.

FIG. 4 shows a conventional example of such a temperature measuring device, and FIG. 4 (a) shows the case of single detection. In the figure, S ₁ , S ₂ , and S _n are temperature detection sensors by a thermistor, which are attached to the temperature detection points (not shown). A ₁ , A ₂ , and A _n are the temperature sensors S ₁ , S ₂ , and S _n , _{respectively.}
3 shows an insulating amplifier connected to the amplifier for amplifying the detection signal of the sensor. The temperature detection sensor is directly attached to the conductor to which a high voltage is applied, such as a thyristor, transformer or disconnector, and the temperature is measured while the temperature is being detected, so an insulation amplifier is used. The high voltage main circuit is insulated from the control unit. Reference numeral 41 indicates a temperature monitoring device, and the temperatures of a plurality of temperature detection points are individually measured and monitored by the temperature monitoring device 41.

FIG. 4B shows a conventional example of time division detection.
With one insulation thickener A, the detection signals of the temperature detection sensors S _{1 to} S _n are transmitted through the relay contacts R _{y1 to} R _yn.
The relay contacts R _{y1 to} R _yn of each relay are _cyclically switched by the switching device 52 and the temperatures of the plurality of temperature detection parts are input to the temperature monitoring device 51 in a time-division manner and measured. The switching device 52 includes, for example, an oscillator O, a counter C, and a relay circuit R.

[0005]

In the case of single detection as shown in FIG. 4 (a), since the detection signals of a large number of temperature detecting portions are respectively amplified by the insulation thickener, a large number of insulation thickeners are provided. It is necessary, the cost of the entire temperature measuring device increases, and the entire device becomes large and uneconomical.

Further, in the case of detecting by time division of FIG. 4 (b), only one amplifier is necessary and the above problem can be solved, but since the contacts are constantly switched at a constant time interval, the life of the contacts is shortened. However, there is still a problem that the measurement is too short to measure for a long time.

Therefore, according to the present invention, in the measurement by the time-divisional detection described above, when the detected temperature is low and safe, the switching interval time of the contacts is increased to reduce the switching frequency of the contacts to prolong the life of the contacts. It aims to provide a temperature measuring device of this kind.

[0008]

Means for solving the above-mentioned problems in the present invention is to detect the temperature detection signals of a plurality of temperature sensors by switching them in time division by means of contacts of a switching device for cyclically switching, In a temperature measuring device adapted to measure a detection signal through a common amplifier, the output signal of the amplifier is compared with an allowable temperature set value in which an allowable temperature of a temperature measurement target portion is determined in advance. The difference signal is taken out, and the temperature detection signal closest to the allowable temperature set value in one cycle or predetermined cycle of the contact switching is taken out and the temperature detection signal is compared with the difference signal. When it becomes smaller, the switching device is controlled to shorten the contact switching time.

Further, the switching device is provided with a voltage selection circuit for controlling the contact switching time, and the voltage selection circuit is provided with a plurality of reference voltage set values corresponding to predetermined contact opening / closing times. The output signal of the amplifier is compared with a reference voltage value for which a frequency switching value is determined in advance, the difference signal is taken out, and the reference voltage setting value is selected according to the magnitude of the difference signal to select the reference voltage value. The contact switching time is controlled by the voltage setting value.

[0010]

According to the first aspect of the present invention, when there are no failures in the plurality of temperature measuring parts and there is a margin in the difference with the set allowable temperature, the relay contacts are switched at a predetermined time interval and sampling is performed. When the temperature of each temperature measurement unit is measured and the temperature rises at one of the temperature measurement units and the difference from the allowable temperature becomes small, the switching interval of the relay contact becomes short. The measurement density is increased.

According to the second aspect of the present invention, if there is no failure in the plurality of temperature measuring parts and there is a margin of difference from the set allowable temperature, it is regarded as normal and the relay is relayed at a predetermined time interval. The temperature of each temperature measuring part is measured by switching the contact points and sampling. Also, if there is a temperature rise at one location during one cycle of switching or during a predetermined cycle and the difference from the allowable temperature becomes small, a part fails. Considering that there is a temperature rise, the contact closing time of the measuring part is lengthened and closely monitored,
Shorten the contact closing time of other normal measuring parts.

Further, when there is a temperature rise at two or more temperature measurement points, it is considered as a total failure, and the overall sampling interval is shortened to increase the monitoring density.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiments shown in the drawings. FIG. 1 is a block diagram of a first embodiment of the present invention, showing a case of temperature measurement of a semiconductor device. In the figure, reference numeral 1 denotes a semiconductor device, which includes a forward conversion circuit 11, a DC reactor 12, and an inverter circuit 13.
S ₁ , S ₂ , and S ₃ are a forward conversion circuit 11 and a DC reactor 1
2, the temperature detection sensor provided in the main circuit portion of the inverter circuit _{13, R y1, R y2,} R y3 relay RY _1, RY _2,
The contact of RY ₃ is connected between the temperature detecting sensors S ₁ , S ₂ , S ₃ and the common insulation amplifier A.

Reference numeral 2 denotes a switching device which converts a frequency proportional to a voltage into a V / F oscillation circuit 21, a counter 22 and a relay RY.
A relay drive circuit 23 that cyclically operates _{1 to} RY ₃ , a reference voltage generation circuit 20 that sets a reference level of the V / F oscillation circuit 21, and an allowable temperature setter that presets and sets the allowable temperature of the temperature measurement target portion. 24, counter 22
The selector 25 for synchronizing the temperature detection signals of the temperature detection sensors S _{1 to} S ₃ with the allowable temperature set value in synchronization with the signal, and the signal closest to the allowable temperature set value of the temperature detection sensors S _{1 to} S ₃ And a minimum level holding circuit 26 for outputting a negative signal to the reference voltage generating circuit 20. Reference numeral 3 denotes a comparison circuit, and the comparison circuit 3 synchronizes with a selector 25 a switching cycle of the contacts of the relay, and an insulation amplifier A that widens the setting signal of the allowable temperature setting device 24 and the detection signal of each temperature detecting sensor. And the signal ΔT of the difference is input to the determination circuit 4 and the minimum level holding circuit 26. The determination circuit 4 measures the temperature change state for each temperature detection sensor, and issues an abnormal alarm or takes a predetermined protection means when the temperature rises to a predetermined temperature. The minimum level holding circuit 26 holds the minimum signal value during one cycle of temperature measurement or a predetermined number of cycles, and the output of the minimum level holding circuit 26 is input to the comparison circuit 27, and the reference voltage generation circuit 20. Add as a negative amount to the reference level of. A temperature indicator 5 converts the output signal of the insulation amplifier A into a temperature indicator.

As described above, in the present embodiment, the switching device 2 is provided with the allowable temperature setting device 24 and the minimum level holding circuit 26, the difference between the allowable temperature setting value and the measured temperature is taken out, and a plurality of temperature detecting parts are detected. In one cycle (or several cycles) in which the temperature measurement of 1 is performed, the value with the smallest difference from the allowable temperature set value is detected, and this detected signal is compared with the allowable temperature set value, and the detected temperature rises. If there is no difference between the allowable temperature setting value and the allowable temperature setting value, the output frequency of the V / F oscillation circuit 21 is increased to shorten the relay switching time interval, and the difference is large and there is a margin with the allowable temperature. In this case, lower the output frequency and extend the switching time for monitoring. Therefore, when the temperature detection part is normal, the temperature is monitored by sampling at long time intervals, so that the number of times the relay contacts are opened and closed can be extremely reduced.

In this embodiment, the allowable temperature set value is an absolute temperature value. However, 24 is set as the allowable temperature increase value by using the temperature increase value obtained by subtracting the detected temperature from the ambient temperature. Good. The output signal of the minimum level holding circuit 26 may be output when the difference from the allowable temperature set value approaches a predetermined range.

2 is an embodiment of the invention of claim 2 and is the same as FIG. 1 except for the switching device, and therefore detailed illustration is omitted, and parts having the same names or the same functions as in FIG. 1 are the same. The reference numerals are given and the description is omitted.

In this embodiment, when there is a margin in comparison with the allowable temperature set value at all of the plurality of temperature measuring points, when only one position approaches the allowable temperature set value, or at several measuring points. In this case, the contacts are switched at the optimum time interval for each approaching the allowable temperature set value.

In FIG. 2, reference numeral 30 denotes a switching device of the second embodiment, which is different from FIG. 1 in that a comparator 31, a frequency switching reference setting device 32, a memory circuit 33, and a voltage (or frequency) selecting circuit 34 are provided. It is a point to have. Comparator 3
1 is the output of the insulation amplifier A, that is, the detected temperature signal,
A signal ΔT, which is the difference from the setting value of the allowable temperature setting device 24, is input and compared with the setting value of the frequency switching reference setting device 32, and the difference signal is stored in the memory circuit 33. Voltage (frequency)
The selection circuit 34 has a plurality of reference voltages V _{1 to} V ₄ , and the output signal ΔT of the comparison circuit 3 stored in the storage circuit 33.
_One of V _{1 to} V ₄ is selected according to the value of (signal of difference from allowable temperature). The reference voltages V _{1 to} V ₄ are closed for different contact points R _{y1 to} R _y3 of relays t _{1 to} t _{4, respectively.}
To set. For example, V ₁ → t ₁ , V ₂ → t ₂ , V ₃ → t ₃ , V
Set as ₄ → t ₄ and take various cases into account t ₁ ~
Set the time of t ₄ .

For example, when considering the following three cases, t ₁ to t ₄ are set as shown in Table 1, respectively.

[0021]

[Table 1]

However, V ₂ <V ₁ <V ₃ , V ₁ <V ₄ t ₂ > t ₁ > t ₃ , t ₁ > t ₄ FIG. 3 shows the temperature measurement at three points A, B and C. The case of each of the cases in Table 1 is shown in FIG.
In the case of “ΔT ≧ reference” at all measurement points C (Case 1), the contact closing time t ₁ is the same for all points A, B, and C and is switched at a predetermined time interval.

FIG. 3B shows the case where only the point A has "ΔT <reference value". In this case, it is necessary to regard the temperature of the point A in detail, considering it as a partial failure. Therefore, the measurement time t ₂ at the point A is made long, and the points B and C are switched in a short time like t ₃ . Therefore, the number of contact switchings is the same as in the case of (a), but the temperature condition at the failure point can be observed in detail.

In FIG. 3C, “ΔT <at point A and point B”
In the case of "reference value", when the temperature is close to the allowable temperature value by more than 2 measurement points, it is considered as a failure of the entire device, and points A, B, C
The whole point is changed over in a short time of t ₄ and measured, and the whole is observed at high density.

Although the case where the insulating thickener is used has been described in the embodiments of FIGS. 1 and 2, the insulating thickener is not necessarily required depending on the place of use.

[0026]

In the embodiment of FIG. 1, when the temperature measuring points as a whole have a margin compared to the allowable temperature, the switching time of each measuring point is lengthened to slow down the measuring time, and When any one of the points approaches the allowable temperature due to the occurrence of an abnormality, the switching time is shortened.Therefore, when measuring the temperature over a long period of time, an abnormal situation is extremely rare. The number of operations and the number of times the contacts are opened and closed drastically decreases, and once an abnormality occurs,
Since the measurement density is increased, the life of the entire measuring device is extended, and a highly reliable temperature measuring device can be obtained.

Further, in the embodiment of FIG. 2, when the temperature measuring points are all normal, the switching time of each measuring point is lengthened,
If one measurement point is abnormal, the measurement time at the abnormal measurement point is lengthened, the measurement time at the normal measurement point is shortened, and if there are two or more abnormalities, the overall switching time is shortened. As a result, the measurement density at the required measurement points can be increased when necessary, and when the temperature is to be measured over a long period of time, the number of times the relay used for measurement switching and the number of operations are the same as in the embodiment of FIG. The number of times of opening and closing the contact is drastically reduced, and the reliability of the entire temperature measuring device can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is an operation explanatory diagram of the present invention.

FIG. 4 is an explanatory diagram of a conventional example. (A) ... Single detection. (B) ... Time division detection.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 2, 30 ... Switching device, 21 ... V / F oscillation circuit, 22 ... Counter, 23 ... Relay drive circuit,
24 ... permissible-temperature setting unit, 25 ... selectors, 26 ... minimum level holding circuit, RY ₁ to Ry ₃ ... relay, R _y1 to R _y3 ... contacts, 3 ... comparison circuit, 4 ... determination circuit, 31 ... comparator, 32 ... Frequency switching reference setter 33, memory circuit, 3
4 ... Voltage (frequency) selection circuit.

Claims (2)

[Claims] 1. A temperature measuring method in which temperature detection signals of a plurality of temperature sensors are cyclically switched by contact of a switching device to be detected in a time division manner, and the detection signals are measured through a common amplifier. In the device, the output signal of the amplifier is compared with an allowable temperature set value in which the allowable temperature of the temperature-measuring part is determined in advance, and a difference signal is taken out. The temperature detection signal that is closest to the allowable temperature set value is taken out, the temperature detection signal is compared with the difference signal, and when the difference becomes small, the switching device is controlled to switch the contact. A temperature measuring device characterized by shortening the time. 2. A temperature measuring method in which temperature detection signals of a plurality of temperature sensors are cyclically switched by contact of a switching device for time-division detection and the detection signals are measured through a common amplifier. In the device, the switching device is provided with a voltage selection circuit for controlling contact switching time, and the voltage selection circuit is provided with a plurality of reference voltage set values corresponding to predetermined opening and closing times of the contacts, and the amplification is increased. The output signal of the instrument is compared with the reference voltage value for which the frequency switching value is determined in advance, and the difference signal is extracted, and the reference voltage setting value is selected according to the magnitude of the difference signal, and the reference voltage setting value is selected. The temperature measuring device is characterized in that the contact switching time is controlled by the.