JPS6111680A - Testing device for normal watt-hour meter instrument error - Google Patents

Abstract

PURPOSE:To test the instrumental error of normal watt-hour meters different in constant, etc., without performing any complicate calculation by using a microcomputer. CONSTITUTION:The instrmental constant Kx of the normal watt-hour meter to be tested is set with a setter 2 and when a reference watt-hour meter and the watt-hour meter to be tested are supplied with electric power, the microcomputer 1 calculates the measurement rotational frequency N of the normal watt-hour meter to be tested on the basis of an equation III and determine a computed pulse Ps corresponding to a display quantity on the basis of an equation II. Further, arithmetic based upon the equation I is carried out by using the pulse Ps to find the instrumental error epsilon automatically, and the error is displayed on a display device 3, thus testing the instrumental error of the normal watt-hour meter with the different constant speedily and easily without performing any complicate calculation previously. In the equations, Vs is the applied voltage of the reference watt-hour meter, Is the applied current of the reference watt-hour meter, Ks the instrumental constant of the reference watt-hour meter, Vx the applied voltage of the watthour meter to be tested, and Ix the applied current of the watt-hour meter to be tested.

Description

DETAILED DESCRIPTION OF THE INVENTION The conventional test method will be explained in order to gain an understanding of the test method for ordinary watt-hour meters.

One test method for ordinary watt-hour meters is a comparative test method in which the instrumental error is determined from the ratio of pulses generated from a reference watt-hour meter to pulses generated from an ordinary watt-hour meter under test. Conventionally, tests were conducted using a circuit as shown in FIG. In this method, the control input (9) from the circuit synchronized with the pulses generated by the normal watt-hour meter under test and the input (8) from the pulse generated by the reference watt-hour meter are combined (logical AND with +1). Tori p,
Count the pulses generated by the reference power/dynamometer using the decimal counter 0]).

The instrumental difference was calculated using the first equation. FIG. 4 is a timing diagram of this, and shows the counting state of pulses generated by the base yarn watt-hour meter during period (3) in which the control input is "open".

By the way, the signal from the control input (9) indicates that the gate 0υ is "
The "open" period is the "open" period of the normal watt-hour meter under test as explained earlier.
Since the value differs depending on the difference in the rated current, rated voltage, and meter constant, Ps shown in the first equation also changes each time the meter rating or meter constant changes. Of course, in the test method described here, it is necessary to obtain this PS in advance, and the second equation is the calculation formula for obtaining Ps.

To explain the second equation, the numerator represents the pulse generated by the standard watt-hour meter, that is, the amount of pulses obtained by W/F conversion.Similarly, the denominator represents the pulse generated by the normal watt-hour meter under test. The above are conventional test methods and calculation formulas. Next, the calculation method and test method according to the present invention will be explained.

The verification tolerance of this device is ±2.5 at a power factor of 0.5.
Considering that the power factor is 2 when the power factor is 1, the third
After determining N using the formula and Ps using the second formula, the microcomputer shown in FIG. 1 counts the N pulses applied to input 1 using the third formula. This N means the sum total of one pulse generated per revolution of the ordinary watt-hour meter under test. During this summation period (corresponding to T in Fig. 4), the reference pulses generated by the reference watt-hour meter input to the human power 2 in Fig. 1 are counted, and calculated by a microcomputer according to the first formula to calculate the instrumental error. Get it. The reason why 200o is placed in the third equation in this series of steps is to take into account the verification tolerance as explained earlier.

As explained above, in the past, this type of test was not possible without complex calculations before and after the test, but by using a single device.

The significance of being able to perform instrumental error tests on ordinary watt-hour meters simply by setting the specified rating and meter constants for the ordinary watt-hour meter under test is significant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of this device, FIG. 2 is a setting device and display of this device, FIG. 3 is a principle diagram of a conventionally used circuit, and FIG. 4 is a timing diagram thereof. License applicant Kyoenden Sokki Co., Ltd. Rir! ■ Ya 2 Kuchiju 3 Showa 4 Li procedural amendment (method) % formula % 1. Indication of case 1988 Patent Application No. 133510
No. 2, Title of the invention Ordinary electricity meter difference testing device 3,
Relationship with the case of the person making the amendment Patent applicant Address: 1-26-8-4 Higashirokugo, Ota-ku, Tokyo Date of amendment order: September 25, 1980 5 Number of inventions increased by amendment: None 6. Subject of correction
Detailed Description of the Invention 7, Contents of Amendment Deleting formulas between the specification and drawings, and adding "Detailed Description of the Invention"
The entire text has been corrected as attached. DETAILED DESCRIPTION OF THE INVENTION - A conventional testing method will be described in order to gain an understanding of the testing method for ordinary watt-hour meters. One test method for ordinary watt-hour meters is a comparative test method that determines the instrumental error between the pulses generated from the standard watt-hour meter and the pulses generated from the ordinary watt-hour meter under test. Conventionally, tests were conducted using a circuit as shown in FIG. In this method, the control input (9) from the circuit connected to the pulses generated by the normal watt-hour meter under test and the input (8) from the pulses generated by the reference watt-hour meter are logically ANDed using Ql. 1
The pulses generated by the reference watt-hour meter were counted with a 0-base counter 01), and the instrumental error was determined using the first equation of first order. 6- PX ε=-X100ﾃ□-1st formula % formula % () PS ke Represented quantity (calculation pulse) Px is the true value (counting pulse) Figure 4 is a timing diagram of this, and the period during which control input is possible The counting state of the reference watt-hour meter generated pulses in (1) is shown. By the way, the period during which the gate a'D is "open" with Hayabusa from the control input (9) is determined by the "rated current", "rated voltage" and "meter constant" of the normal watt-hour meter under test as explained earlier. Since it differs depending on the difference, Ps shown in the first equation will also change every time the rating of the meter or the constant of the meter changes. Of course, in the test method explained here, this Ps
It is necessary to obtain Ps in advance, and the second linear equation is the calculation equation for obtaining Ps. Here, Ps is the expressed quantity (calculation pulse) ■θ is the reference watt-hour meter applied voltage M Is is the reference watt-hour meter applied voltage n is the reference watt-hour meter instrument constant (rθv/kwh) Vx is the ordinary watt-hour meter under test The applied voltage MIx is the applied current of the ordinary watt-hour meter to be tested (Al failure is the meter constant of the ordinary watt-hour meter to be tested - (re v/kwh) Nri The number of rotations measured by the ordinary watt-hour meter to be tested is 1 molecule is the pulse generated by the reference watt-hour meter, i.e. W
/ indicates the amount of pulses obtained by F conversion; similarly, the denominator is the amount of pulses generated by the normal watt-hour meter under test. The above are the test methods and calculation formulas that have been used in the past. - Next, the calculation method and test method according to the present invention will be explained in detail. The verification tolerance of this device is ±2.5 at a power factor of 0.5.
Considering that the power factor is 2 when the power factor is 1, N is determined by the third equation of first order. N= This N means the summation. During this summation period (corresponding to T in Fig. 4), the base pulses generated by the reference watt-hour meter input to input 2 in Fig. 1 are counted, and the Calculate with a microcomputer using the formula to obtain the instrument difference.The reason why 2000 is placed in the third formula in this series of steps is to take into account the verification tolerance as explained earlier. As explained above, in the past, unless complex calculations were made before and after the test, this type of test would require the use of nine devices. The significance of being able to perform instrumental error tests on ordinary watt-hour meters simply by setting specified ratings and meter constants is significant.

Claims (1)

[Claims] This device consists of a series of circuits consisting of a microcomputer (1), a setting device (2), and a display device (3). A normal electricity meter difference test device (hereinafter referred to as the device) that can perform an instrumental difference test by setting the specified ``rated current'', ``rated voltage'', and ``meter constant'' equal, and can display the results as an instrumental difference.