JP4634740B2 - Power switching time measuring device - Google Patents

Description

  The present invention relates to a power supply switching time measuring device for measuring a power supply switching time of a power system having a plurality of power supplies.

  A conventional power supply switching time measuring device will be described with reference to FIG.

  FIG. 3 shows a configuration of a conventional power supply switching time measuring device in a power system composed of two power supplies and a common load.

  As shown in the figure, the power of the power source 31a is supplied to the load 34 when the switch 32a is turned on, and the power of the power source 31b is supplied to the load 34 when the switch 32b is turned on. The switch 32a and the switch 32b are controlled by the control device 35, and the power source is switched during a power failure time managed so that both the power sources 31a and 31b are not turned on simultaneously.

  On the other hand, the control device 35 periodically corrects the change in the switching time due to the characteristic change of the equipment and circuit of the power facility and the aging deterioration.

  For this reason, in the conventional power supply switching time measuring device, the switching in the switching execution command is performed by the auxiliary contact 33a of the switch 32a, the auxiliary contact 33b of the switch 32b, and the switching execution command of the control device 35 taken into the measuring device 36. The time from opening of the switch 32a to closing of the switch 32b and the time from opening of the switch 32b to closing of the switch 32a in the switching execution command are measured as the switching time of the power source.

  The conventional power supply switching time measuring apparatus described above has the following problems.

  (1) Since there is an error between the operation time of the switch auxiliary contact and the operation time of the switch main pole, a measurement error with the actual power supply switching time occurs.

  (2) It is difficult to manage the accuracy with respect to the switching time on the actual circuit due to a change in operating time characteristics due to aging of the switch body and auxiliary contacts.

  The present invention has been made to solve the above problem, and is capable of accurately measuring the power switching time of the actual system without being influenced by the characteristics of the switch and the signal propagation delay between devices. An object is to provide a time measuring device.

  In order to achieve the above object, the present invention provides a power supply switching time measuring device for measuring a power supply switching time in an electric power system that switches a plurality of power supplies and supplies them to a load. First, a difference between the first power supply side voltage and the load side voltage among the plurality of power supply side voltages and the load side voltage detected by the means is obtained by detecting each of the voltages. Means for obtaining a difference voltage and obtaining a second difference voltage by obtaining a difference between the voltage on the second power source side and the voltage on the load side, and the first difference voltage and the second difference obtained by this means It is characterized by comprising means for obtaining a predetermined ratio using voltage, and means for measuring a time when the predetermined ratio obtained by this means exceeds a predetermined value.

  According to the present invention, two or more power supplies can be switched within a controlled time period, and the exact power switching time of the equipment to be supplied to the load can be measured, so that the power supply switching can be realized within the managed time period. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a configuration of a power source switching time measuring device in an electric power system composed of two power sources and a common load as one embodiment of the present invention.

  As shown in the figure, the power of the power source 1a is supplied to the load 4 when the switch 2a is turned on, and the power of the power source 1b is supplied to the load 4 when the switch 2a is turned on. The switch 2a and the switch 2b are controlled by the control device 5, and the power is switched in a power failure time managed so that the two power sources 1a and 1b are not turned on simultaneously.

  On the other hand, the control device 5 periodically corrects the change of the switching time due to the characteristic change of the equipment and circuit of the power facility and the aging deterioration.

  In this system, a power source 1a side auxiliary transformer 3a, a power source 1b side auxiliary transformer 3b, and a load 4 side auxiliary transformer 7 are provided. Take in the measuring device 6.

  FIG. 2 is a processing block diagram showing the internal configuration of the measuring device 6.

  In the figure, the secondary side voltages Va, Vb, Vn of the auxiliary transformers 3 a, 3 b, 7 are converted into arbitrary analog values by the input conversion means 11. This analog value is stored by sampling and holding means 12 with sampling at a constant period. The analog value stored in the sampling hold means 12 is converted into a digital value by the A / D conversion means 13 and stored in the data storage means 14.

  The difference voltage amplitude value calculation means 15 obtains the difference voltages Δva and Δvb from the sampling values of the plurality of input voltages Va, Vb, Vn stored in the data storage means 14 by the following mathematical formula.

Δva = Va−Vn
Δvb = Vb−Vn
The ratio calculation means 16 obtains the ratio Δve from the difference voltages Δva and Δvb obtained by the difference voltage amplitude value calculation means 15 by the following formula.

Δve = (| Δva + Δvb | +0.001) / (| Δva−Δvb | +0.001)
The comparison determination unit 17 compares the ratio Δve obtained by the ratio calculation unit 16 with an arbitrarily determined value kΔve and passes the comparison determination result to the power supply switching time calculation unit 17.

  When it is determined that Δve detected by the comparison determination unit 17 exceeds an arbitrarily determined value kΔve, the power supply switching time calculation unit 18 counts the excess duration time. In this way, the power supply switching time is measured by counting the excess duration time.

  As described above, in the present embodiment, the voltage difference between the two power supply side voltages and the load side voltage is obtained, and the predetermined ratio calculated using the two difference voltages exceeds a predetermined value. Therefore, it is possible to measure the power supply switching time of the actual circuit. Since the change in the load voltage caused by the opening of the operation-side power supply is canceled by turning on the subsequent power supply, the operation is performed so as to measure the time as close as possible to the switching of the actual system.

The figure which shows the structure of the power supply switching time measuring apparatus which concerns on one Embodiment of this invention. The processing block diagram which shows the detailed structure of the principal part in one Embodiment of this invention. The figure which shows the structure of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b ... Power supply 2a, 2b ... Switch 3a, 3b, 7 ... Auxiliary transformer 4 ... Load 5 ... Control device 6 ... Measuring device 11 ... Input conversion means 12 ... Sampling hold means 13 ... A / D conversion means 14 ... Data storage means 15 ... difference voltage amplitude value calculation means 16 ... ratio calculation means 17 ... comparison determination means 18 ... power supply switching time calculation means

Claims (1)

In the power switching time measuring device for measuring the power switching time of the supplied electric power system to the load by switching a plurality of power supply, the plurality of power source side voltage, and means for detecting a voltage of the load side, respectively, this means with obtaining the voltage of the detected plurality of power source side, and of the voltage of the load side, the first differential voltage obtains the difference between the voltage and the voltage of the load side of the first power source side, the first by using the means for obtaining a second differential voltage determines the difference between the second voltage and the voltage of the load side of the power supply side, the first differential voltage and the second differential voltage obtained by the means A power switching time measuring apparatus comprising: means for obtaining a predetermined ratio; and means for measuring a time during which the predetermined ratio obtained by the means exceeds a predetermined value.

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