RU2261511C2 - Auxiliary power supply system for power station unit - Google Patents

Abstract

FIELD: electrical and power engineering; power stations using unit-type power supply circuits.

SUBSTANCE: proposed system designed to provide for auxiliary power supply to station power unit, as well as to maintain desired voltage level across switchgear installation and auxiliary power consumers of power unit both in the course of variations in the parameters of the latter and in case of short circuits in station switchgear installation and adjacent supply mains has generator, unit transformer, station switchgear and auxiliary power installations, operating and additional auxiliary-power transformers. Line leads of generator stator winding are connected through unit transformer and operating transformer to switchgear installations and to auxiliary-power installations, respectively. Second winding of additional transformer is connected in parallel with power circuit between secondary winding of operating transformer and auxiliary-power switchgear installation. Primary winding of additional transformer is connected in series with power unit load circuit, that is, this transformer runs under load-specified conditions. Power supply system may be provided with additional auxiliary-power switchgear installation, additional transformer being provided with additional secondary windings. This power supply system may be also provided with current-limiting reactors.

EFFECT: enlarged functional capabilities, enhanced operating reliability.

3 cl, 9 dwg

Description

The invention relates to the electric power industry and can find application in powerful power plants with block schemes for generating electricity.

A known power supply system for auxiliary needs of a power unit of a power plant, which contains a generator, the linear terminals of the stator winding of which is connected through a block transformer to a distribution installation of a power plant and through a working transformer of own needs to a distribution installation of auxiliary needs of a power unit [Neklepayev B.N. The electrical part of power plants and substations: Textbook for universities. - 2nd ed., Revised. and add. - M .: Energoatomizdat, 1986. - 640 p., P. 371, Fig. 8.24, b].

However, the reliability of such a power supply system for the auxiliary needs of a power unit of a power plant with respect to maintaining the required voltage level on power receivers of its own needs is not high enough both during a change in power unit mode and during short circuits in a distribution plant of a power plant and an adjacent electrical network. To maintain the operation of auxiliary power consumers while reducing voltage at the auxiliary distribution system, control devices under load on auxiliary working transformers and complex backup power systems are used.

The basis of the invention is the task of creating a power supply system for the auxiliary needs of the power unit of the power plant, in which the introduction of new elements and the connections between them would ensure the maintenance of the required voltage level on the power receivers of the auxiliary needs of the power unit both during changing power unit modes and during short circuits in the distribution installation power plants and the adjacent electrical network and thereby increase the reliability of the power unit.

The task is achieved in that the auxiliary power supply system of the power unit of the power plant, containing a generator, the linear terminals of the stator winding of which are connected through a block transformer to the distribution installation of the power plant and through the working auxiliary transformer to the distribution unit of the auxiliary needs of the power unit, according to the invention, contains an additional auxiliary transformer, the secondary winding of which is connected in parallel to the electrical circuit between the secondary th winding working auxiliary transformer, and distribution installation own power needs, the primary winding of the additional auxiliary transformer is connected in series in the electrical circuit between the line terminals of the stator winding of the generator and the point of attachment of the primary winding of auxiliary transformer working.

The introduction of an additional auxiliary transformer and new connections between the elements will allow, by parametrically changing the amount of current in the secondary winding of the additional auxiliary transformer when changing the current of the generator stator winding, to ensure the maintenance of the required voltage level at the distribution unit and power units auxiliary needs of the power unit both during the change of power unit modes and during short circuits in the distribution installation of the power plant and adjacent to it the electric network and thereby increase the reliability of the work.

The task is also achieved by the fact that in the auxiliary power supply system of a power unit of a power plant, the primary winding of an additional auxiliary transformer is connected in series with the neutral leads of the generator stator winding.

This provides an additional reduction of the voltage level on the insulation of the primary winding of the auxiliary auxiliary transformer, and thereby increases the reliability of operation.

The task is also achieved by the fact that in the auxiliary power supply system of a power unit of a power plant, the primary winding of an additional auxiliary transformer is connected in series to the electrical circuit between the connection point of the primary winding of the auxiliary auxiliary working transformer and the line leads of the primary winding of the block transformer.

This allows you to reduce the current load of the primary winding of an additional auxiliary transformer and thereby increase the reliability.

The task is also achieved by the fact that in the auxiliary power supply system of a power unit of a power plant, the primary winding of the auxiliary auxiliary transformer is connected in series with the neutral leads of the primary winding of the block transformer.

This allows to reduce the current load of the primary winding of the auxiliary auxiliary transformer to reduce the voltage level on the insulation of this winding and thereby increase the reliability.

The task is also achieved by the fact that in the auxiliary power supply system of a power unit of a power plant, the primary winding of an additional auxiliary transformer is connected in series to the electrical circuit between the line leads of the secondary winding of the unit transformer and the distribution plant of the power plant.

This provides a significant reduction in the current load of the primary winding of the auxiliary auxiliary transformer and thereby increases the reliability of operation.

The task is also achieved by the fact that in the auxiliary power supply system of the power unit of the power plant, the primary winding of the auxiliary auxiliary transformer is connected in series with the neutral terminals of the secondary winding of the block transformer.

This allows for a significant decrease in the current load of the primary winding of the auxiliary auxiliary transformer to further reduce the voltage level on the insulation of this winding and thereby increase the reliability.

The task is also achieved by the fact that the auxiliary power supply system of the power unit of the power plant contains an additional distribution unit for the auxiliary needs of the power unit, while the auxiliary auxiliary transformer is made with an additional secondary winding, which is connected to the auxiliary auxiliary distribution system, and the additional auxiliary transformer is made with additional a secondary winding that is connected in parallel to an electrical circuit between additional secondary winding of the working transformer of auxiliary needs and an additional distribution unit for the auxiliary needs of the power unit.

This allows you to further expand the previously mentioned advantages to power supply systems of their own needs, which contain an additional distribution installation of their own needs, and thereby increase the reliability.

The task is also achieved by the fact that the auxiliary power supply system of the power unit of the power plant contains a current-limiting reactor, the winding of which is connected in series to the electric circuit between the secondary winding of the auxiliary auxiliary transformer and the connection point of the secondary winding of the auxiliary auxiliary transformer.

This allows you to reduce the level of currents during short circuits in the electrical circuit of auxiliary needs, as well as to further increase the voltage level at the distribution installation and power consumers of auxiliary needs during short circuits in the distribution installation of the power plant and the adjacent electrical network, and thereby increase the reliability of operation.

The task is also achieved by the fact that the current-limiting reactor is made double with an additional winding in the auxiliary power supply system of the power unit of the power plant, while one ends of the reactor windings are connected respectively to the secondary windings of the auxiliary and auxiliary auxiliary transformers, and the other ends of the reactor windings are interconnected and connected to the distribution unit for the auxiliary needs of the power unit.

This allows you to additionally provide the necessary voltage level on the distribution installation and electrical appliances of their own needs during normal conditions and thereby increase the reliability.

The technical essence and principle of operation of the proposed power supply system of the own needs of the power unit of the power plant explain figure 1 ÷ 9. Figure 1 ÷ 6 shows the auxiliary power supply systems of a power unit of a power plant with a generator, a block transformer (BT), a working auxiliary transformer (RTSN), distribution plants of a power plant (RUES) and auxiliary needs (RUSN), as well as an additional auxiliary transformer (DTsN); figure 7 - power supply system with additional RUSN; on Fig - power supply system with a current-limiting reactor (TR); figure 9 - power supply system with a dual reactor with an additional winding.

The auxiliary power supply system of the power unit of the power plant (Fig. 1) contains a generator 1 with a stator winding 2, a block transformer (BT) 3, a working auxiliary transformer (RTSN) 4, a distribution plant of a power plant (RUES) 5, a distribution unit of auxiliary needs (RUSN) 6 power units and additional auxiliary transformer (DTSN) 7. Linear outputs 8 of the secondary winding 9 BT 3 connected to RUES 5. The primary winding 10 RTSN 4 is connected to the electrical circuit between the linear leads 11 of the winding 2 of the stator gene 1 and the linear leads 12 of the primary winding 13 BT 3 in an arbitrary location 14. The secondary winding 15 of the RTSN 4 is connected to the RUSN 6. The secondary winding 16 DTSN 7 is connected in parallel to the electrical circuit between the secondary winding 15 of the RTSN 4 and the RUSN 6 at an arbitrary location 17. The primary winding 18 DTSN 7 is connected in series to the electrical circuit between the linear terminals 11 of the winding 2 of the stator of the generator 1 and the place 14 connecting the primary winding 10 RTSN 4.

Figure 2 shows the power supply system in which the primary winding 18 of the DTSN 7 is connected in series with the neutral terminals 19 of the winding 2 of the stator of the generator 1.

Figure 3 shows the power supply system in which the primary winding 18 of the transformer substation 7 is connected in series with the electric circuit between the connection point 14 of the primary winding 10 of the PTCH 4 and the line leads 12 of the primary winding 13 BT 3.

Figure 4 shows the power supply system in which the primary winding 18 of the DTSN 7 is connected in series with the neutral terminals 20 of the primary winding 13 BT 3.

Figure 5 shows the power supply system in which the primary winding 18 of the DTSN 7 is connected in series to the electrical circuit between the linear terminals 8 of the secondary winding 9 BT 3 and RUES 5.

Figure 6 shows the power supply system in which the primary winding 18 of the DTSN 7 is connected in series with the neutral terminals 21 of the secondary winding 9 BT 3.

The power supply system may contain additional distribution units for auxiliary needs, and the working and additional auxiliary transformers can be performed with additional secondary windings. Figure 7 shows a variant of such a power supply system, which in addition to the electrical components in figure 3 contains one additional RUSN 22, and RTSN 4 and DTSN 7 are made with additional secondary windings 23 and 24, respectively. An additional secondary winding 23 of the RTSN 4 is connected to an additional RUSN 22, and an additional secondary winding 24 of the DTSN 7 is connected in parallel to the electric circuit between the additional secondary winding 23 of the RTSN 4 and the additional RUSN 22 at an arbitrary location 25.

The power supply system may include one or more current limiting reactors. On Fig shows a variant of such a power supply system, which in addition to the elements of the power supply system of figure 3 contains a current-limiting reactor 26, the winding of which 27 is connected in series with the electrical circuit between the secondary winding 15 of the PTCH 4 and the connection point 17 of the secondary winding 16 of the DPSN 7.

In the power supply system, the current-limiting reactor can be made double with an additional winding. Figure 9 shows a variant of such a power supply system, in which, unlike the power supply system of Fig. 8, the current-limiting reactor 26 is made double with an additional winding 28, while one ends of the windings 27 and 28 of this reactor 26 are connected respectively to the secondary windings 15 and 16 PTCH 4 and DTSN 7, and the other ends of the windings 27 and 28 of this reactor 26 are interconnected and connected to RUSN 6.

The power supply system of the auxiliary needs of the power unit of the power plant works like this.

In the power supply system in Fig. 1, DTSN 7 operates in the mode specified by the load of the current generator 1, which passes through the primary winding 18 and is transformed into the secondary winding 16 of the DTSN 7. When the load of the generator 1 changes, its current changes, and, therefore, the currents in the primary 18 and secondary 16 windings of DTSN 7, which provides counter-regulation of the voltage level on the RUSN 6 and allows the use of PTCH 4 without on-load tap-changers, which, as you know, are one of the least reliable elements of traditional power supply systems. In normal modes of a power unit, the auxiliary load load is distributed between PTCH 4 and DTSN 7, while the desired distribution is achieved with a certain transformation coefficient of DTSN 7, the value of which in the general case can be a complex number. The voltage levels on the insulation of the primary winding 18 DTSN 7 both in normal conditions and during earth faults in an arbitrary place of the electric circuit at the generator voltage correspond to voltage levels on the insulation of the winding 2 of the stator of the generator 1 from the side of the linear outputs 11 in similar modes of the traditional power supply system without DTSN 7. In the proposed power supply system, the rated power of RTSN 4 may be less, and its reactance is greater than in the traditional power supply system without DTSN 7. Therefore, the current level s during short circuits in RUSN 6 decreases. During short circuits in RUES 5 and the adjacent electric network, the voltage at the linear terminals 11 of the stator winding 2 of the generator 1 decreases, but the current from the generator increases, which means that the currents in the primary 18 and secondary 16 of the DTSN windings increase, which ensures maintenance the required voltage level on the RUSN 6 and, thereby, on electrical appliances of their own needs.

In the power supply system of FIG. 2, in contrast to the power supply system of FIG. 1, the primary winding 18 of the DTSN 7 is connected in series with the neutral terminals 19 of the winding 2 of the stator of the generator 1, as a result of which the voltage level on the insulation of the primary winding 18 of the DTSN 7 is significantly reduced as in normal conditions , and during earth faults in an arbitrary place of the electric circuit at the generator voltage, which facilitates the working conditions of this insulation.

In the power supply system of FIG. 3, in contrast to the power supply system of FIG. 1, in operating modes, a smaller current will pass through the primary winding 18 of the DTSN 7, the value of which will be equal to the difference between the currents of the winding 2 of the stator of the generator 1 and the primary winding 10 of the RTSN 4, which leads to reduce heat loss of power in the primary winding 18 DTSN 7 and facilitates the conditions of its work on heating.

In the power supply system of FIG. 4, in contrast to the power supply system of FIG. 1, in operating modes, a lower current will pass through the primary winding 18 of the DTSN 7, the value of which will be equal to the difference between the currents of the winding 2 of the stator of the generator 1 and the primary winding 10 of the RTSN 4, which leads to reduce heat loss in power in the primary winding 18 DTSN 7 and will facilitate the conditions of its work on heating. Due to the fact that the primary winding 18 of DTSN 7 is connected in series with the neutral terminals 20 of the primary winding 13 BT 3, the voltage level on the insulation of the winding 18 of DTSN 7 is significantly reduced both in normal conditions and during earth faults in an arbitrary place on the generator circuit voltage, which facilitates the working conditions of this insulation.

Block transformers of power supply systems of power units of power plants are increased, that is, the values of the currents of the secondary windings of these transformers are less than the values of the currents of their primary windings. Therefore, in the power supply system of FIG. 5, both in normal conditions and in the conditions of external short circuits in RUES 5 and in the adjacent electrical network, a current will pass through the primary winding 18 of the DTSN 7, the value of which is less than the value of the corresponding current in the electrical installation in FIG. .1 in similar modes, which will lead to a decrease in heat losses of power in the primary winding 18 of DTSN 7 and will additionally facilitate the conditions of its work on heating, but the voltage level on the insulation of this winding will correspond to the voltage level on the insulation of the secondary winding 9 BT 3 from the side of its linear conclusions 8.

In the power supply system of FIG. 6, both in normal conditions and in the conditions of external short circuits in RUES 5 and in the adjacent electrical network, a current will pass through the primary winding 18 of the DTSN 7, the value of which is less than the value of the corresponding current in the electrical installation in FIG. 1 in similar modes, which will lead to a decrease in heat losses of power in the primary winding 18 of DTSN 7 and will further facilitate the conditions of its work on heating. Due to the fact that the primary winding 18 of DTSN 7 is connected in series with the neutral terminals 21 of the secondary winding 9 BT 3, the voltage level on the insulation of the winding 18 of DTSN 7 is reduced, which facilitates the working conditions of this insulation.

In the power supply system in Fig. 7, the presence of an additional RUSN 22 and the execution of the RTSN 4 with an additional winding 23 provide a reduction in current levels during short circuits in the distribution units of the auxiliary needs of the power unit in comparison with the power supply systems in Figs. 1-6. Moreover, the performance of DTSN 7 with an additional secondary winding 24, which is connected in parallel to the electric circuit between the additional secondary winding 23 of the RTSN 4 and the additional RUSN 22 at an arbitrary location 25, provides operating modes and their advantages similar to the operating modes and advantages of power supply systems in Fig. 1 -6, respectively.

In the power supply system of Fig. 8, the presence of a current-limiting reactor 26 increases the equivalent reactance of the branch with RTSN 4 by the reactance of the winding 27 of this reactor. This makes it possible to additionally maintain the required voltage level at RUSN 6 during short circuits in RUES 5 and the adjacent electrical network in the case when the RTSN 4 reactance value is insufficient. In addition, the presence of a current-limiting reactor 26 leads to a decrease in the level of currents during short circuits in RUSN 6.

In the power supply system of FIG. 9, the execution of the reactor 26 is doubled with an additional winding 28, in addition to the advantages of the power supply system of FIG. 8, during normal operation of the power unit provides improved conditions for maintaining the required voltage level on the RUSN 6 by reducing the equivalent reactance of the dual reactor with respect to RUSN 6.

The proposed power supply system for the auxiliary needs of a power unit of a power plant can be implemented during the technical re-equipment and reconstruction of existing and construction of new power units of power plants.

Claims (3)

1. The auxiliary power supply system of a power unit of a power plant, comprising a generator, the linear leads of the stator winding of which are connected via a block transformer to the distribution installation of the power plant, and a working auxiliary transformer, the primary winding of which is connected to the electrical circuit between the linear leads of the stator winding of the generator and the primary winding of the block transformer while the secondary winding of the working transformer of auxiliary needs is connected to a distribution installation e auxiliary needs of the power unit, characterized in that it contains an additional auxiliary transformer, the secondary winding of which is connected to the electric circuit between the secondary winding of the auxiliary auxiliary transformer and the auxiliary unit distribution unit, while the primary winding of the auxiliary auxiliary transformer is connected in series to the electric circuit or between the linear terminals of the stator winding of the generator and the connection point of the primary winding of the working trans auxiliary transformer, either in series with the neutral leads of the generator stator winding, or between the point of attachment of the primary winding of the working transformer of the auxiliary needs and the linear leads of the primary winding of the block transformer, or in series with the neutral leads of the primary winding of the block transformer, or in series between the linear leads of the secondary winding of the block transformer and distribution installation of the power plant, or in series with the neutral terminals of the secondary skeins of block transformer. 2. The system according to claim 1, characterized in that it contains a current-limiting reactor, the winding of which is connected in series to the electric circuit between the secondary winding of the auxiliary auxiliary transformer and the connection point of the secondary winding of the auxiliary auxiliary transformer. 3. The system according to claim 1, characterized in that it contains an additional distribution unit for auxiliary needs of the power unit, while the working auxiliary transformer is made with an additional secondary winding, which is connected to an additional distribution unit for auxiliary needs, and an additional auxiliary transformer is made with an additional secondary a winding that is connected to an electrical circuit between an additional secondary winding of a working auxiliary transformer and an additional p the distribution unit for the auxiliary needs of the power unit.

Images