SU1171931A1 - Generator-rectifier installation - Google Patents

Abstract

GENERATOR-RECTIFIED INSTALLATION, containing a synchronous generator with the first and second three-phase stator windings, connected each according to the "star with combined zero points and parallel to each other" circuit, the first and second rectifier converters with the same output buses, the first cable route connecting the outputs the phases of the first stator windings with the same inputs of the first rectifying converter, the second cable route connecting the phase leads of the second stator winding with the same the second inputs of the second rectifying converter, the third and fourth cable paths connected respectively to the phase terminals of the first and second stator windings, three current sensors, the outputs connected to the inputs of the protection unit made of series-connected elementers, threshold and actuator elements, different the fact that, in order to increase operational reliability by detecting short circuits in the generator windings, cable runs and on rectifier converters, the ends of the phases the third cable route is connected to the single-input inputs of the second rectifying converter, and the ends of the phases of the fourth L cable route are connected to the same inputs of the first rectifying converter, two current sensors are installed in two opposite phases of the first cable route, and the third current sensor is in the third phase second cable route. with so

Description

The invention relates to electrical engineering and is intended for use in autonomous electric power systems. The aim of the invention is to increase the operational reliability by detecting short circuits in the generator windings, cable runs and on the busses of the rectifier converters. FIG. 1 shows a functional installation diagram; in fig. 2 - directions of currents at three-phase short circuits at the outputs of the three-phase winding of the generator and at the input of the converter; in fig. 3 - the same, with two-phase short circuits x; in fig. 4 and 5 - the same, during valve breakdown; in fig. 6 - the same, with coil closures in three-phase windings of the generator. The rectifier generator set contains a synchronous generator 1 with the first 2 and second 3 parallel three-phase stator windings connected by each star, the zero points of which are combined, the first 4 and second 5 rectifying converters, the first cable route 6, are connected terminals A, B, C of the first winding 2 of the stator with like inputs (A, B, C) of the first rectifier converter 4, and the second cable route 7 connecting the terminals of the phases of the second winding 3 of the stator with the same inputs of the second rectifier the transmitter 5, three current sensors 8-10, outputs connected to the inputs of the protection unit, made of the addition element 1 1, the threshold element 12, the actuating element 13. The sensors 8 and 9 are installed respectively in phases A and C of the first cable route 6, sensor 10 installed in phase B of the second cable route 7. A third cable route 14 connects the phase leads of the first winding 2 of the stator to the same inputs of the second rectifier converter 5, a fourth cable route 15 connects the phase leads of the second winding 3 of the stator to the same inputs of the second winding A rectifier converter 4. The output buses of converters 4 and 5 of the same name are combined and connected through a switching device 16 to a common load 17. The output of the actuating element 13 is connected to the generator 18 control unit of the generator 1, the switching-off windings 19 of the switching device 16, the winding 20 of a short circuit 21 connected to the inputs of the converters 4 and 5. The installation works as follows. Under normal operating conditions, as well as with external short circuits at load 17 (point Ki, Fig. 1), the currents flowing through the cables to which current sensors 8-10 are installed are symmetrical, their sum is zero. The signal at the output of the element 11 is missing. Protection in these modes does not work. The emergence of three-phase short circuits at the terminals of the first or second three-phase generator windings leads to a change in the phases of the output voltages of the sensors. Thus, in the event of damage at the terminals of the first three-phase winding (Fig. 2a), the currents flowing through current sensors 8 and 9 change their phase by 180 °, which leads to a violation of symmetry in the secondary sensor circuits, the appearance of a signal at the output element 1 1 and triggered protection. Three-phase short circuits at the inputs of converters 4 or 5 are characterized by the fact that emergency currents flow only through two sensors, for example, 8 and 9 (Fig. 26), if the busbars of the converter 4 are damaged or through the current sensor 10 if the tires of the converter 5 are damaged. The signal triggers protection. In case of two-phase short-circuits at the terminals of the first or second three-phase windings, the emergency current flows only through two current sensors. The sum of the output voltages of the latter gives a nonzero signal leading to the operation of the protection. For example, a two-phase short circuit of phases A and B at the terminals of the first three-phase winding (Fig. 3A) leads to the flow of emergency current through sensors 8 and 10. The secondary voltages of sensors change their phase by 180 °, while at the output of element 1 1 is a signal that triggers protection. A feature of the emergency modes for two-phase short circuits at the inputs of converters 4 and 5 is that the emergency current flows only through one of the three current sensors, which results in a signal at the output of the element 11, leading to the protection to be triggered. For example, in the case of a two-phase short circuit of phases A and B on the buses of the converter 4 (FIG. 36), an emergency current flows through the current sensor 8. The output of element 11 is a signal equal to the output voltage of sensor 8, which triggers protection. A breakdown of the valve, for example, 22 (FIG. 4) in the cathode group of converter 4, at the end of its conduction interval, creates two circuits (c) for the flow of emergency current in the AC circuit. In this mode, the sum of the currents Аи в flows through the sensor 8 of the damaged phase A, and through the sensor 10 of the current of the phase B - the circuit current c. At the output of the element 11, a signal is turned on, under the influence of which the protection operates. When valves in anode groups of converters 4 and 5, for example valve 23, breakdown at the end of its conduction band (Fig. 5), a two-phase short circuit begins to develop after a positive voltage appears on the anode of valve 22

with respect to the anode of the valve 24. In this case, two circuits (A and B) are also created, for the flow of emergency current.

In this mode, the sum of the currents of the circuits A and B flows through the sensor 8 of the damaged phase A, and the current of the circuit B flows through the sensor 10 installed in the phase B. The output of element 11 is a signal that triggers the protection.

Similarly, the processes in the installation proceed and protection is triggered when other valves are triggered.

With coil closures in three-phase windings of the generator, for example, in phase A of the first three-phase winding, longitudinal voltage asymmetries occur. Under the influence of the resulting voltage, the zero-sequence currents circulate through the cable paths 14 and 15, creating a closed loop. The zero sequence currents flowing through the sensors 8-10 cause a signal at the output of the element 11 to provide a trip.

This option of installing current sensors on cable trails is not the only one. The table shows other possible installation options for current sensors.

The invention makes it possible to increase the reliability of the power supply to consumers in autonomous electric power systems, since there are almost all types of damage to generator-rectifying installations in it.

First converter second converter

Phase Phase

ABC + - + ABC.

+ -f - - 7

+ +

+

- +

- +

L --- i- +

Note: “+” indicates the location of the current sensor.

Shy

J /

I i i-

J

.

Sr

 t

Vuz.J

five

Fig4

.

i tvi

Claims (1)

GENERATOR-RECTIFIER INSTALLATION, comprising a synchronous generator with the first and second three-phase stator windings, each connected according to the "star" scheme with the combined zero points and parallel to each other, the first and second rectifier converters with the combined output buses of the same name, the first cable route connecting the phase leads the first stator winding with the inputs of the first rectifier converter of the same name, the second cable route connecting the phase leads of the second stator winding to the same the inputs of the second rectifier converter, the third and fourth cable paths connected respectively to the phase outputs of the first and second stator windings, three current sensors, outputs connected to the inputs of the protection unit made of series-connected addition element, threshold and actuator elements, characterized in that, with the purpose of increasing operational reliability by detecting short circuits in the generator windings, cable routes and on the buses of rectifier converters, the ends of the phases of the third Yelnia tracks connected to the inputs of the same name of the second rectifying converter, and fourth ends of the cable tray phase - to the like inputs of the first rectifier converter, two current sensors are provided in the two phases of opposite first cable tray, and the third current sensor - in the third phase of the second cable line. Figure 1