UA46132C2 - METHOD OF MEASUREMENT OF MAXIMUM VALUE OF EXTERNAL MAGNETIC FIELD STRENGTH OF M-FIDER VARIABLE VARIABLE - Google Patents

Abstract

The present invention relates to the magnetic measurement technique and can be used for monitoring intensities of external magnetic fields induced by a multifeeder ac distribution board. The proposed method involves separately measuring phase angles of each feeder magnetic fields, determining the phase angles of the feeder magnetic fields corresponding to the reverse direction of the feeder currents, defining an arbitrary feeder as the reference feeder, and selecting the feeders for which phase angles of magnetic fields are more (less) than the phase angle of the reference feeder magnetic field corresponding to the forward direction of this feeder current, but less (more) than the phase angle of the reference feeder magnetic field corresponding to the reverse direction of this feeder current, and measuring intensity of the external magnetic field induced by the ac distribution board. Then, in order of decreasing (increasing) the feeder magnetic fields relative to the phase angle of the reference feeder magnetic field corresponding to the forward direction of this feeder current, the feeder is selected for which the phase angle of the magnetic field differs minimally from the phase angle of the reference feeder magnetic field corresponding to the forward direction of this feeder current. The selected feeder is turned out if it is under voltage and turned on if it is not under voltage. Then the intensity of the magnetic field induced by the ac distribution board is repeatedly measured. The above-mentioned operations are repeated until all measurements (where m is a number of the feeders) are performed. The measurement results are used for determining the maximal intensity of the external magnetic field induced by the ac distribution board. The proposed method allows the number of operations in the measurement process to be reduced.

Description

Description of the invention

The invention relates to the field of magnetic measurements and can be used to control the intensity of 2 external magnetic fields (IZMP) of multi-feeder AC switchboards.

AC power multi-feeder switchboards are sources of SMF. which disrupt the normal functioning of various magnetically sensitive devices located in the zone of influence of the ZMP. Therefore, when solving a number of practical problems on the electromagnetic compatibility of sources of magnetic resonance and magnetically sensitive devices, there is a need to control the strength of the field of sources of magnetic resonance (11.

A multi-feeder switchboard is characterized by multimode, due to the fact that its feeders can work individually and in different combinations with each other. In order to determine the maximum value of the tension of the ZMP t - feeder switchboard in different modes of its operation, it is necessary to perform the volume of measurements M - 2/7 - 1, which increases significantly with increasing t. It is clear that even with t - 10 it is problematic to perform the volume of measurements M - 1023.

Of the known methods, the method of measuring the external magnetic field of a multi-feeder alternating current distribution board (21, which consists in measuring the magnetic field of the board in different modes of its operation, namely: when passing through each feeder its nominal current, determine the sequence of decreasing phases of the intensity of the magnetic fields of various feeders relative to the phase of the largest field of the feeder, which is chosen as the reference, then sequentially supply the nominal current to each feeder of the circuit, starting from the reference feeder, when the feeders are turned on in the order of decreasing phase angles, and for each value of the current, the resulting magnetic field of the shield is determined, then nominal currents are sequentially fed into each feeder of the circuit when the feeders are turned on in the order of increasing phase angles with subsequent determination of the resulting magnetic fields.

The disadvantage of the known method is that when the values of the phases of the magnetic fields of the feeders are 0...360O, this method does not solve the task of determining the maximum value of the voltage of the magnetic field of the shield based on the results (o) of measuring the magnetic field of the shield in some modes of its operation.

Let's prove it for the case of a five-feeder distribution board (t - 5), when the vectors of the measured strengths of the magnetic fields of the board feeders are located in four quadrants of the complex plane, Fig. 1. We take the 20th fourth feeder, which has the largest field size, as the reference. They turn it on and measure the intensity of the resultant field of the shield Na - H,A (i.e., fig. 2). Then turn on the feeders in the order of decreasing phase angles and measure the intensity of the resulting magnetic field of the shield, i.e.: "- turn on the 3rd feeder and measure the field (tb) Well NN. N,; F 7 include the 2nd feeder and measure the field(s) I, - N.N. N,; it includes the 1st feeders measure the field (t.g) Н.-Н, НН, НН, « оз, , . ! - c turn on the 5th feeder and measure the field (etc.) and - NN, НВ, Б. After that, these measurements are repeated when the feeders are turned on in the order of increasing phase of the intensity of their magnetic fields relative to the phase of the field of the reference fourth feeder: - these - . in t. Include the "4th and 5th feeders and measure the field (i.e.) n.-H, H,:

Ф turn on the 1st feeder and measure the field (the same) Н.-Н, НИ. N,; - may . - со b» Turn on the 2nd feeder and measure the field (t. z) H,-NAN,H,H,. that) According to the results of the measured values of the field of the shield H in, according to Fig. 2, take the maximum value of the ZMP of the shield. However, in reality, as can be seen from fig. 2. It does not correspond to the maximum value of the tension of the ZMP of the shield, because when the combination of the first, second, third and fifth feeders is turned on (i.e.) Nlah U Nu? Nv.

Thus, the known method, in general, does not solve the problem of determining the maximum value of the shield's magnetic field strength based on the results of measuring the strength of its magnetic field in several modes of its operation. eat) The invention is based on the task of creating such a method that will reduce the complexity of measuring the voltage of the multi-feeder switchboard when determining the maximum value of the intensity of its voltage.

Such a technical result is achieved by the fact that in the method of measuring the maximum voltage value of the ZMP t - feeder distribution board, which includes the operations of measuring the magnetic field of the board in different modes of its operation, the phases of the magnetic fields of each feeder are measured separately and the phases of the magnetic fields of the feeders are determined in the reverse direction of the current in them, include an arbitrary feeder that is chosen as the base, as well as feeders whose field phases are greater (less) than the field phase of the base feeder when the current flows in it, but less (greater) than the field phase of the base feeder when the current is reversed in with it, the external magnetic field of the shield is measured, then in the order of decreasing (increasing) phase angles of the feeder fields relative to the phase of the magnetic field of the base feeder, a feeder is selected, the phase of the magnetic field of which differs minimally from the phase of the field of the base feeder in the direct direction of the current in it, and, depending on from the electrical state of the newly selected feeder, it is turned off if it finds are under current, and turn on if it is without current, after which the external magnetic field of the shield is measured again, and then similar operations are repeated until only 2t of measurements are performed, based on the results of which the maximum value of the intensity of the external magnetic field of the shield is determined

An example of performing measurements is explained with the help of drawings, while the figures show: 70 Fig. 1, Fig. 2 - describes the method of measurement for the prototype.

Fig. 1 - vectors of measured intensities of the magnetic fields of the five-feeder distribution board (t - 5).

Fig. 2 is a vector diagram that explains the method of measuring the maximum value of the intensity of the magnetic fields of the five-feeder distribution board (prototype).

Figure 3 shows a vector diagram that explains the essence of the proposed method, where the number of feeders 75 is assumed to be five (t - 5); the number of possible modes of operation of the five-feed shield M - 2 5-1 831; Well..no (points 1 - 5) - complexes of the intensity of the magnetic fields of the first-fifth feeders having phases respectively si..«rv; - No... No - complexes of the intensity of the magnetic fields of the feeders when the currents in them are changed on 1807 phases.

The method is implemented as follows. Measure the phases f/..«ro of the intensity of the magnetic fields of the first to fifth feeders of the shield, respectively, and determine the phases of the intensity of the magnetic fields of the feeders when the phases of the currents in them are changed by 1807 (ф - фи 1807, and - 1...5). Include an arbitrary feeder, for example, a third feeder with a phase of physical field intensity; which is chosen as the basic one, as well as the fourth feeder, the field intensity phase of which is fi ho fu ho Fi t 180", and measure the voltage of the ZMP of the shield No - Well Well Well (item 6). Determine the feeder with the nearest smaller, compared to " ru, the value of the phase of the field strength. Such a feeder is the second s 29 (field strength No, phase fo). which has no current. Turn on the second feeder and measure the voltage of the shield’s short circuit (U

H7: N» Z Well, I am N, (v. 7).

Further, similar operations are repeated after turning on or off each subsequent one in decreasing order of the phase of the field strength of the feeder relative to the phase of the field strength of the magnetic field of the base - the third feeder until all 2t measurements are performed, namely: turn on the first feeder and measure the field No - No - No k Na I Nu (v. 8); so disconnect the fourth feeder and measure the field Nu - H, - H, 4 H, (item 9); - shawl . . , (Se) include the fifth feeder and measure the field Nu N, N.N, NN. (vol. 103; her

They turn OFF the third Feeder and MEASURE the field No, sh- N, nya n. In N. (t11); disconnect the second feeder and measure the LV field, - LV, LV, (item 12); "40. them . - Нн 5 , - s disconnect the first feeder and measure the field « (item 5);

I" include the fourth feeder and measure the field Я, x Н, 3 Н. (item 13); " er r r i3 5 1. 5 (T.13); . y I chl. x s a nn -z5 SET OFF THE FIFTH feeder and MEASURE the field a (T.4). sh»

The largest of the 2t - 10 measured values of the magnetic field strength will be the maximum value b of the strength of the magnetic field of the five-feeder distribution board, i.e. N dah - Nil (item 11), because with any other combinations of feeders working simultaneously, the value of the board's ZMP will be determined on the complex plane by 50 points that lie inside the region, the boundary of which is the sides of a closed decagonal hodograph, i.e.:

Co.)

F) name) 60 b5

. fluff. . sha t.. n and

Na, Noah), Na. (1.3); N. t- N, - No (v. 14); No - N, I N.a.15);

No t N, Well (v. 16); N,. t H, "No (p. 17; H, - p, "Well (p. 18);

N,o - n, nya n. (vol. 19); and sh- n., -Po(t2ou Nu - N, -n, N,(t21u; -і1 y and zu. sha . . oyu NN" - NN, Nyt.22); Na - PO, "Well i Well (v. 23); On - H, - H, - H, (1.24);

Not BUT; Nt25); No yah No - N, - Nt.26); Well I Well B, -Nt.2t, - 4 . required - » On NN, NN, A N (t28); Nyu I N, Z I NN, I No (v. 29);

But - But I B NP, 4 N. (30); Well, - N, 3 8, 4 N.N, I M, (1.31).

Thus, the claimed method allows, based on the results of 2t measurements, to determine the maximum value of the intensity of the external magnetic field of the t-feeder distribution board of alternating current, which. ultimately, provides a reduction in the volume of measurements by (27 - 1) / 2t times.

Sources of information 1. GOST R 50010-92. Compatibility of technical means electromagnetic Power electrical equipment. Norms of low-frequency periodic magnetic field parameters. - Entered on 01.07.93. - M.: Publishing House of Standards, 1993. -5p. with 2. ace. 892370 USSR, MKY СО01К 33. The method of measuring the external magnetic field scattering by a multi-feeder AC switchboard / B.V. Klymenko, O.O. Yevseeva, V.F. Karpuk, E. O. Polyakov (USSR). - Mo2911192/18; Announced on 04/22/80; Publ. 23.11.81, Bull. Mo47. -227.p. with zo

Claims (1)

The formula of the invention is a method of measuring the maximum value of the intensity of the external magnetic field of an alternating current feeder - distribution board, which consists in measuring the magnetic field of the board in (Te) different modes of its operation, which differs in that the phases of the magnetic fields of each feeder separately | determine the phases of the magnetic fields of the feeders when the current direction is reversed in them, include an arbitrary feeder, which is chosen as the basic one, as well as feeders whose field phases are greater (less) than the phase of the field of the basic feeder when the current flows in it directly, but less (greater) than the phase the field of the base feeder with the reverse direction of the current in it, and measure the external magnetic field of the shield, then in the order of decreasing (increasing) phase angles " of the feeder fields relative to the phase of the magnetic field of the base feeder, choose a feeder whose magnetic field phase C 70 differs minimally from the phase of the base field feeder in the direct direction of the current in it, and depending on the electrical state of the newly selected feeder, it is turned off if it is under current, and turned on if it is de-energized, after which the external magnetic field of the shield is measured again and similar operations repeat until only 2t of measurements are performed, based on the results of which the maximum value of the intensity of the external magnet is determined one field of the shield. sh" (22) - about 50 Ko) F) name) 60 b5