SU682837A1 - Galvanomagnetic measuring active power converter - Google Patents

Description

one

The proposed galvanomagnetic transducer of active power is intended for use in automatic control and monitoring devices of electrical power systems, in particular, in emergency control automation devices.

Galvanomagnetic active power transducers for oscillographing or measuring power in three-phase three-wire circuits to obtain a purely cosine characteristic are known in the voltage circuit containing a voltage separation transformer, and in the current circuit a Hall multiplier, 1.

The disadvantages of the transducers are that they do not compensate for the harmonic components of the Hall emf (harmonic components are compensated only for a three-phase symmetric AC system).

Of the known galvanomagnetic transducers of active power, the technical solution closest to the invention is a galvanomagnetic transducer containing a phase-turning circuit in the form of a frequency filter, necessary for obtaining a pure cosine characteristic, and a Hall multiplier. A Hall multiplier and zener diodes are installed in the current circuit of the converter to protect the Hall semiconductor elements from thermal destruction by a high input current of the converter. Hall multipliers installed in the voltage and current circuit are of different types. 2. Such a converter is characterized by

the following disadvantages: the presence of frequency error in the conversion, the frequency dependence of the EMF of the Hall, due to the phase-frequency characteristic of the frequency filter used as a phase-turn:: circuits in the voltage circuit; the influence of the aperpical component of the short-circuit current on the power line, which causes a short-term surge in the output EMF of the Hall, which is undesirable with high-speed devices of automatic emergency automation, the presence in the output EMF of the components with frequencies higher than 100 Hz, which are caused by a nonlinear magnetic dependence

nmdu1-; qing multiplied Hall current circuit from the input current of the converter.

The purpose of the invention is to eliminate the frequency error of the conversion, reduce the influence of the aperiodic component Jup1, its short-circuit current on the Output Hall voltage of the EMF and reduce the harmonic components in the output. EMF Hall. In order to achieve 11 goals in a galvanomagnetic measuring device, an active power converter, containing two Hall multipliers — in current and voltage and zener diodes — a transreactor is installed in the converter current circuit, the secondary multiplier of the current circuit is connected to the converter current circuit, Hall chain voltage. FIG. 1 shows a circuit diagram of a galvanomagnetic transducer of active power; in fig. Figure 2 shows vector diagrams showing the phase relationships between the electrical and magnetic quantities in the transmitter. Galvanomagnetic measuring active power transducer contains two identical Hall multipliers 1 and 2, respectively, in the voltage circuit and in the current circuit, consisting of sources 3 and 4 of the magnetic field with secondary windings and Hall sensors 5 and 6, transreactor 7, ballast resistors 8-12 and zener diodes 13, included in the secondary current circuit of the converter. The multiplier Hall 1 through the ballast resistor 10, which is necessary to obtain the appropriate angle of resistance of the winding, is connected to the measuring voltage transformer. The Hall sensor 5 is located in the air gap of the magnetic core of the source 3 of the magnetic field and current electrodes through a ballast resistor 9 is connected to the secondary winding of the source 4 of the magnetic field. Thus, the Hall multiplier 1 multiplies the magnetic induction BH and the current / a. voltage chains The Hall 2 multiplier, through ballast resistors 11 and 12, which are necessary to create a coordinated mode of operation of the transreactor and the corresponding winding resistance angle, is connected to the secondary winding of the transreactor. The transreactor creates the necessary phase relationships to obtain a purely cosine response and connects to a current metering transformer. The Hall sensor 6 is located in the air gap of the magnetic core of the source 4 of the magnetic field and current electrodes through a ballast resistor 8 is connected to the secondary winding of the source 3 of the magnetic field. As a result, the Hall multiplier 2 multiplies the magnetic induction ST and the current / rt in the current circuit. Thus, the Hall emf of identical multipliers 1 and 2 of the voltage circuit and the current circuit, respectively, are determined by the expressions bloch / e and sin (w - a - 8) x x /;) + T. + YP + s 5inf sin (u) -cp- | - --aS) X - / fl - / „X mSinfoii -а-8 + where a is the resistance angle of the winding of the magnetic field source, which in the proposed converter is assumed to be - -; 6 - the phase angle between current and magnetic induction in the winding of the source of the magnetic field; P is the phase angle between the emf and the current in the secondary winding of the source of the magnetic field; Ф is the phase angle between the current and voltage of the controlled circuit. The constant components of the EMF of the Hall multipliers are proportional to ...- f // cos (cp + T); Ex, U / cos (f - - {). The harmonic components of the emf of the non-multipliers of the hall are the same and proportional to in, (co) in, (oe) - t // COS (2 (0 - s - 28 - f). The electromotive force at the output of the measuring transducer of active power and is determined only by the double value of the constant component of the emf of each of them, since the harmonic components are mutually destroyed by EJ ,, 2W cos with cos 7. i.e., proportional to the active power of single-phase alternating current, due to the use of a transreactor and identical Hall multipliers In the voltage and current circuit of the proposed active-power galvanomagnetic transducer, the frequency error of the conversion is eliminated, the influence of the aperiodic component of the current on the output Hall voltage and harmonic components on the output voltage of the Hall voltage decreases. can be used in emergency control devices for objects whose currents may contain aperiodic components, as well as for information Sintered computing maschin actuating objects with strongly unbalanced load, for example, electric melting furnaces.

Claims (2)

1.Ovcharenko N. And. And others. The use of galvanomagnetic elements in relay protection and automation. M., “Energie, 1966, p. 111 - 113, fig. 40 2. In the same place 58, fig. sixteen. g loS.K I o Sh.i G n af.H