JP3299674B2 - How to display the current status of the operation of the time limit characteristic - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time limit characteristic for displaying the current operation corresponding value to the time limit characteristic when a relay or the like having a time limit characteristic is installed. The present invention relates to a method for displaying the current operation status.

[0002]

2. Description of the Related Art Overcurrent relays having a time limit characteristic for protecting an electric motor from overload include various operating principles such as a rotating disk type, an air dashpot type, and a resistance temperature type. In any of the methods, since it is impossible to know which operating point is currently set with respect to the set point at which the overcurrent protection operation is performed, the protection operation may be performed at an unintended time and various problems may occur. If it is possible to know which operating point is present at the set point at which the overcurrent protection operation is performed, appropriate measures can be taken. Further, for example, in the case of a harmonic content relay having a time limit characteristic, a countermeasure can be taken by knowing how much danger the delivered device is currently imminent under the location conditions of the customer.

[0003]

SUMMARY OF THE INVENTION As described above,
When a concentration relay, viscosity relay, speed relay, acceleration relay, etc. are installed in addition to the overcurrent relay and the harmonic content relay having the time limit characteristic, the relay does not operate. On the other hand, it was difficult to know how far the operating point has been reached.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has a time limit characteristic that allows the current operating point to be easily known from the operation set point of the time limit characteristic. It is an object of the present invention to obtain a method for displaying the operation status of a characteristic.

[0005]

Means for Solving the Problems] operation current display method inverse time characteristic according to the present invention, harmonics of the harmonic components of the inverse time characteristic showing the relationship between the operating time and the harmonic content of the harmonic component
The cumulative operation time of the operation corresponding value of the relay having the time limit characteristic is obtained from both the wave content and the operation time, and the cumulative operation time of the operation corresponding value is based on the time to reach the operation point of the time limit characteristic. Is displayed.

The relay is a harmonic content relay, and the operation corresponding value is a converted value of a harmonic component of a predetermined harmonic with respect to a fundamental wave.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a view for explaining a method of displaying the current operation state of the time limit characteristic according to the first embodiment of the present invention.
FIG. 9 is a reciprocal time characteristic diagram showing a relationship between a harmonic content (expressed as a percentage) of a harmonic component (fifth harmonic conversion value) of a capacitor current with respect to a fundamental wave flowing through a harmonic content relay and an operation time. The time limit characteristic of the harmonic content relay shown in FIG. 1 is set according to the withstand capability of the protection target (35%, 1800 seconds). The method for displaying the current operation status of the time limit characteristic according to the first embodiment is as follows. With respect to this anti-time limit characteristic, the fifth harmonic conversion value, which is the harmonic component of the capacitor current flowing through the protection target via the harmonic content relay, is used as the operation corresponding value, and the cumulative operation time of the operation corresponding value is obtained. The percentage is displayed based on the time required to reach the operating point of the above time limit characteristic.

During the protection operation of the object to be protected, the fifth harmonic conversion value of the harmonic component is continuously or every predetermined sampling time as an operation corresponding value by using a current detecting means and an arithmetic means (not shown). And as shown in FIG.
Cumulative operating time ΔTx for predetermined fifth harmonic conversion value xn
Find n. On the other hand, from the anti-time characteristic shown in FIG. 1, the time required to reach the operating point of the anti-time characteristic with respect to the predetermined fifth harmonic conversion value xn, that is, the value F (xn) of the Y axis with respect to the predetermined fifth harmonic conversion value xn Ask for. Then, these cumulative operation times Σ
A cumulative value (= ΣTxn / F (xn)) based on Txn and time F (xn) to reach the operation point of the time limit characteristic is obtained, and this is displayed using a display or the like. When the accumulated value becomes “1” or “100%” in percentage, the harmonic content relay as a protection relay operates.

[0009] Therefore, when the equipment such as the harmonic content relay is installed at the customer's site, the cumulative value of the harmonic content relay is set to the customer who is wondering whether the installation was useless after the installation. The stored value of the maximum value) indicates that the temperature of the capacitor and series reactor is rising due to the higher harmonics, and it is possible to explain that if this amount is further increased, the customer's equipment is dangerous and investment is wasted You can be convinced that it was not.

As described above, in the conventional protection relay,
Although it was not possible to know to what extent of the time limit characteristic at present at the time of operation, according to the operation current state display method of the time limit characteristic according to the above embodiment, at present, to what point of the time limit characteristic Since the position is displayed, it is possible to easily know the current operating point with respect to the operation set point of the time limit characteristic.

Embodiment 2 Also, as shown in FIG. 1, the characteristics of an overcurrent relay used as a protection relay when protecting an overload of an electric motor, a transformer, or the like are such that as the current value increases, the operation time becomes shorter. "become. This is to protect the temperature rise due to heat generation based on the current flowing through the windings of the electric motor and the transformer from reaching the temperature rise limit depending on the insulation type of the windings. Since it is difficult to actually measure the temperature of the winding, the temperature is estimated from the value of the current flowing through the winding and the time required for the winding, and the present invention can be applied to a case where an overcurrent relay is used as a protection relay.

That is, for example, when an overcurrent relay is used as a protection relay when a lot of customers are crowded in a ski lift or the like, the display of the accumulated value of the overcurrent is monitored.
If the near trip is detected, the number of occupants can be reduced or the driving speed can be reduced to prevent an emergency stop. Further, in a production facility, various beneficial uses are possible, such as being able to stop the facility due to overload of an electric motor or the like in an important step without causing damage or the like.

In the first and second embodiments, the amount of the object to be detected is the harmonic content and the overcurrent, but the current, the voltage, the temperature, the flow rate, the harmonic current value, and the harmonic Any variable amount such as a voltage value (including a percentage conversion value with respect to the rated value) may be used. In addition to the harmonic content relay and the overcurrent relay, the protection relay includes a temperature relay, a concentration relay, and a viscosity relay. The present invention can be applied to a relay having a time limit characteristic such as a relay, a speed relay, and an acceleration relay.

[0014]

As described above, according to the method of displaying the current operation of the time limit characteristic according to the present invention, the harmonic component of the harmonic component is included.
Harmonic component of anti-time characteristic showing the relationship between prevalence and operating time
The cumulative operation time of the operation corresponding value of the relay having the time limit characteristic is obtained from both the harmonic content and the operation time of the relay, and the accumulated operation time of the operation corresponding value is calculated as the time to reach the operation point of the time limit characteristic. Since the display is made on the basis of the reference, there is an effect that the current operation point can be easily known with respect to the operation set point of the time limit characteristic.

Further, the relay is a harmonic content relay, and the operation corresponding value is a converted value of a harmonic component of a predetermined harmonic with respect to the fundamental wave, so that the temperature of the capacitor or the series reactor rises due to the harmonic. If you add up this much, you can be notified in advance that the customer's equipment is dangerous.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a method for displaying the current operation state of a time limit characteristic according to a first embodiment of the present invention, in which a harmonic component (fifth harmonic) of a capacitor current with respect to a fundamental wave flowing through a harmonic content relay; FIG. 6 is a time limit characteristic diagram showing a relationship between a harmonic content (expressed as a percentage) of a converted value and an operation time.

Claims (2)

(57) [Claims] 1. A motion correspondence value relays from both the harmonic content of the harmonic component of the inverse time characteristic showing the relationship between relative harmonic content of the harmonic component operation time and operation time with the inverse time characteristic And displaying the accumulated operation time of the operation corresponding value on the basis of the time to the operation point of the time limit characteristic. 2. The time limit characteristic according to claim 1, wherein the relay is a harmonic content relay, and the operation corresponding value is a harmonic component conversion value of a predetermined harmonic with respect to a fundamental wave. Operation status display method.