RU1780063C - Method for determining inductive winding dissipation resistance of three-phase synchronous machine - Google Patents

Abstract

The invention relates to electrical engineering, preferably 3 to electrical engineering and industrial energy, and can be used to determine the dependences of inductive scattering resistances at various saturation degrees by means of magnetic scattering fluxes. The aim of the invention is to increase the accuracy of determining inductive scattering resistances of a winding of a synchronous machine. The instantaneous voltage value is measured at one of the phases of the CT.'ITO winding, after raising the excitation current at idle time of the machine, the two other phase stator windings are short-circuited in MON em time, at which the free-phase voltage passes through the zero value. The change in current in the stator windings over time is measured, the experiment is repeated at other initial values of the voltage across the stator winding, and the inductive resistances are determined from the scattering winding »And the scattering of the stator windings, excitation and the damper system at various degrees of saturation of the magnetic flux paths < s scattering .4 ill.sl

Description

The invention relates to electrical engineering, primarily to electrical engineering and industrial energy, and can be used to determine the inductive resistance of scattering of stator windings, excitation and damper system at various degrees of saturation by magnetic fluxes.

Known spog.: E determination of inductive resistances of the scattering of the windings of a three-phase synchronous machine,

A disadvantage of the known technical solution is its poor accuracy.

Closest to the pre (target) is the method of determining inductive

the scattering resistance of the windings of a three-phase synchronous machine, based on two experiments of quenching the magnetic field when the stator winding is open and short-circuited from the idle and three-phase state, setting its short circuit corresponds to -lu excitation at the initial moment of time and the integral of the change in the excitation current in time.

The disadvantages of this method about. The comparatively low accuracy of determining the derivative current changes in

field winding of synchronous machines. This is due to the manifestation of the effect of current displacement in this winding, since the value of the active resistance of the field winding during the quenching of the magnetic field is an indefinite value, different from that measured on a direct current. The indicated difference is most significant at the initial moment of the transition process.

In addition, the method does not allow to determine the influence of the saturation of the paths of the scattering magnetic fluxes of the damper system on the inductive scattering resistance of the latter.

The purpose of the invention is to increase the accuracy and determination of the inductive resistances of the stator and field windings according to the measured parameters.

The goal is achieved due to the fact that in the known method the determination; Inductive laziness is resisted by the scattering of the windings of a three-phase synchronous machine, containing the operation of short circuits; stator phase windings and raising the excitation current to a predetermined level when p is rotated with a nominal frequency; rotor, as well as current measurement in the winding: and the stator and excitation, instead of two experiments of damping the magnetic field, a series of experiments of a sudden short circuit from an idle state at various levels of applied voltage are performed. To exclude the influence of an aperiodic current in the stator winding, which is absent in the prototype method during field damping, in the case of a sudden two-phase short circuit, the two phase windings are shorted when the instantaneous voltage across the third phase winding passes through a zero value (the linear voltage of two short-circuited phase at this moment has a maximum value). The test effect in the proposed technical solution is supplied from the stator by shorting the two phase windings, and not from the rotor by shorting the field winding, which is a physical cause of the error in determining the inductive dissipation resistances of the coils of the synchronous machine in the prototype method.

Figure 1 shows a diagram of the testing of a synchronous machine; in Fig. 2, the stator current curve during a two-phase short circuit of a synchronous machine with a damper system at a nominal voltage at the terminals of the machine idling at maximum 1; and- /

instantaneous value of the linear voltage of the short-circuited phases; in Fig. 3, the excitation current curve for a synchronous machine without damper windings at an instantaneous value of the linear voltage: - ;. equal to zero; Fig. 4 is a diagram replaced by: a synchronous machine with a mutual inductance between the field winding and the equivalent damper circuit -;

different from the mutual inductance between the latter and the stator winding.

As a power source, volvo1; : excitation during the gle / h experiment, take the electric machine ::: expire :: h

backup excitation synchronous Nta bus. As an automatic B1 switch, closing the stator winding circuit to a two-phase short circuit K, a single-phase thyristor E. switch should be used. equipped with a device-, control, fixing the moment under.: -: and the command to turn on the thyristor PG switch at the instant of transition of the instantaneous value of the linear voltage, Hji-ismpo 7 voltage voltage transformer, black -: maximum (amplitude) value,

The instantaneous values of the TG KD8 in the phase stator winding and with excitation, respectively converted by a current transformer and a measuring shunt, are recorded by an automated device.

Physical phenomena that occur in a synchronous machine during a sudden short circuit of two phases, the voltage between which passes through a maximum: excludes the occurrence of a free aperiodic current in the stator, which causes only the leakage in the stator winding

odd harmonics (including the fundamental, industrial frequency), and in the winding and damper system only even current harmonics.

When implementing the method,

the following operations: assemble the test circuit in accordance with figure 1; accelerating the rotor of the machine to the rated speed using a turbine Sdl Turbo and hydrogenerators; set value

DC current in the field winding at a level corresponding to the value of the initial current during a two-phase short circuit, equal to the nominal value, which is provided at the open circuit voltage

move

SW

X dsHOM.

where xd is the supertransitive inductive RSTIVA € ;; 5Is fiO at the same time; DZNN1M and ;:;

data of the factory calculation formulas of the machine, rel. units;

Is.nom - rated current of the stator winding, equal to 1 rel. manually starting the control device; using a single-phase thyristor switch, turn on one of the two phases of the stator winding (connected to each other by a short-circuit to k) by applying to the control unit input a signal generated by the control unit at the instant the instantaneous voltage value of the free phase passes through the zero value; measuring with the control device pS the instantaneous value of the free phase voltage, the currents in one of the phase stator windings and the excitation winding; experiments of a sudden two-phase short circuit are repeated sequentially with the values of the effective voltage of the stator winding at idle of the machine equal to 0.3; 0.5; 0.7 and 1.0 UHOM;

determined from experimental data using the relationship

(is2 (o);

from the first experiment (Is2 (0) 1 rel. units) the unsaturated values of the field winding parameters and the effective damping circuit are determined: xff nenas, X (JD nenas;

carry out an optimization procedure for the analysis of the expression, determined from the data of two-phase short circuit experiments at voltages of 0.3; 0.5; 0.7 and 1.0, UHOM, values of KS, Kf, KD, form expressions for analytical determinations; inductance LS

LTi

scattering resistance at given current values in the stator windings, excitation and the equivalent circuit of the damper system.

The proposed method can be applied under the conditions of production and operation of turbo-generators.

Claims (1)

The claims A method for determining the inductive resistance of the windings of a three-phase synchronous machine, comprising the steps of measuring the voltage across the stator winding and the excitation current in the mode idling the machine followed by damping the field, measuring the current in the field winding when damping the field in the short circuit mode in experiments at different values of the excitation current and determining the inductive resistances of the stator and the field winding from the measured parameters, characterized in that, in order to increase accuracy and determination of the inductive resistance of scattering of the damper system, instantaneous voltage values are measured at one of the phases of the stator winding at idle speed of the machine, two other phases are short-circuited windings at a point in time at which the voltage on the free phase is zero, the current in the field and stator windings is measured in time and the inductive resistance of the stator windings is determined from the obtained data, excitation and damper system at various levels of saturation of the scattering magnetic flux paths. 0. -BEFORE R FIG.