JPS60167620A - Overload monitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an overload monitoring device that is suitable for limiting excessive overload operation and safely monitoring electrical equipment such as transformers. .

[Background of the Invention] FIG. 1 is a conventional block diagram. The amount of electricity flowing into equipment 1 such as a transformer is converted into an amount of electricity suitable for measurement and monitoring by transformers 2 and 3, and then converted into a signal suitable for recording device 7 by converters 4, 5 and 6. 7. The recording device 17 records constantly or selectively by the operator.

In addition, when the device 1 is overloaded, the protection relay 8 operates,
A protective interlock and alarm circuit 9 is operated to prevent damage to the equipment.

In this conventional technique, the protective operation is performed using a fixed setting value of the preservation relay 8, and the past overload conditions are not taken into account, so the overload conditions occur intermittently.

If this occurs without sufficient cooling time for the equipment, there is a risk of damage to the equipment. Furthermore, the recording device 7 also has the inconvenience of having to constantly record or monitor in order to monitor safely.

[Purpose of the invention]

An object of the present invention is to provide an overload monitoring device that can automatically monitor and record the overload state of equipment.

[Summary of the invention]

As shown in FIG. 2, the present invention detects and monitors the amount of electricity flowing into the target device 1 using a transformer 112 and three converters 4', 5' and 6', and an overload detection circuit IO and a setting device. The amount of overload is determined by appropriately calculating the amount of electric power for the overload detected by 11, and the overload integrator 16
Accumulate and store in memory. When the integrator of the overload integrator 16 exceeds a specified value, it is output to the protection interlock and alarm circuit 9, and protection and alarm operations are automatically performed.

The overload amount integrated in the overload integrator 16 is determined according to the cooling time of the device after the overload state is removed and the past overload history.
Overload frequency integrator 17. Overload limit calculation circuit 18. The adjustment switch 19 and the pulse generator 20 subtract or add the values to prepare for the next overload.

Alternatively, the occurrence of an overload state is detected by the overcurrent relay 24 or the like, and the switch 27 is turned on to output the overload state to the recording device.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIGS. 2 and 3.

FIG. 2 is a block diagram showing one embodiment, and FIG. 3 is a block diagram showing one embodiment.

It is an explanatory diagram of the operation.

In Fig. 2, the voltage to the target device 1 is:

Transformer 3. It is input to the device through a converter 4'.

On the other hand, the current flowing into device 1 is transferred to transformer 2. converter 5'
is input to this device through. These voltage and current signals are input to the converter 6' and transmitted to the overload detection circuit 10 as a power amount signal.

The overload detection circuit 10 compares the output of the setter 11 with the overload amount as an output, and outputs the proportional integral circuit 12. Input to maximum overload detection circuit 13. The proportional integral circuit 12 outputs the input from the overload detection circuit 10 as an appropriate proportional integral calculation output to the pulse conversion circuit 15, and the output of the pulse conversion circuit 15 operates the overload integrator 16.

The maximum overload detection circuit 13 detects the maximum overload value, and inputs an overload number signal that takes the maximum overload value into consideration to the overload number integrator 17 to operate it.

When the overload condition is removed, the output of the overload detection circuit 10 becomes zero, and the output of the proportional-integral circuit 12. Pulse conversion circuit 15.
The output of the maximum overload detection circuit 13 becomes zero one after another. As a result, the output of the NOT circuit 23 is input to the timer 22, the switch 21 is operated after the set time, and the subtraction or addition circuit is utilized. The ia switch 19 is controlled by the output of the overload limit calculation circuit 18 and operates the overload integrator 16 by the output of the pulse oscillator 20. The overload limit calculation circuit 18 stops operating when the output of the overload integrator 16 and the output of the overload number integrator 17 are balanced.

When the integrated amount of the overload integrator 16 exceeds a predetermined set value, it is output to the protection interlock and alarm circuit 9, and a protection or alarm operation is performed.

Further, an overload state is detected in advance by an overcurrent relay 24, a switch 27 is turned on, and data necessary for analysis such as voltage, current, power, integrated amount, etc. is recorded by a recording device. When the overload condition is removed, the timer 25 is operated by the output of the NOT circuit 26, the overcurrent relay 24 is automatically reset to 1, the switch 27 is opened, and the recording device is stopped.

In FIG. 3, if the equipment load changes as shown in (a), in the first overload, the overload integrator 16 integrates during period A1, and during period B1, After holding the integrated amount of the overload integrator 16 for the set time t1 of the timer 22, the integrated amount is attenuated by the output of the pulse generator 20, and the attenuation is stopped at the overload frequency integrator output C1,
The output of the overload integrator 16 is held.

Similarly to the first overload, the second circuit is also overloaded, after the overload integrator 16 integrates during the period A2, and after holding the integrated amount for the period t1, the integrated amount is attenuated. In this case, the third overload condition has occurred at point r] where the integrator of the overload 1ir1 integrator 16 has not reached the output C2 of the overload frequency integrator 17, so the switch 21 is immediately opened. , the overload integrator 16 is integrated again. When the alarm and protection interlock operation value is exceeded at point X in the middle of period A3, the overload integrator 16 outputs an output to the protection interlock and alarm circuit, and performs protection and alarm operation. This output is reset at point Y.

In the embodiment, for the sake of simplicity, the attenuation of the integrated amount is set at a constant rate, but it is also possible to change the attenuation rate depending on the magnitude of the load.

〔Effect of the invention〕

According to the present invention, not only is overload monitoring and protective operation of equipment performed completely automatically, but also records of overload events are automatically recorded, including before and after the overload, so that safe operation can be achieved. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional example, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of the operation of an embodiment of the present invention. 16... Overload integrator, 20... Pulse transmitter. Agent Patent Attorney Akio Takahashi Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. An overload monitoring device for equipment, characterized in that it automatically takes past overload history into consideration and performs monitoring or protection.