RU2576664C1 - Device for uninterrupted power supply - Google Patents

Abstract

FIELD: energy.

SUBSTANCE: use: in electric power engineering. Device comprises backup generator, a unit for isolation with power system, consisting of a rectifier, serially connected with charging device and storage battery, switch, series-connected with storage battery, rectifier and inverter, switches for connecting stand-alone power plant to the main alternating-current bus, means for automatic disconnection of consumers connected to the main alternating-current bus control system connected to stand-alone power plant, standby generator, switch for connection of the accumulator battery to inverter , devices of automatic backup, one of which is connected in parallel to the switch for connection of stand-alone power plant to alternating-current bus and the other-parallel to the switch for connection of reserve generator to the main alternating-current bus and thyristor switch, connected in parallel to the switch for connection with the system isolation unit, as well as a switch, mounting AC buses of reserve generator to the rectifier.

EFFECT: two-stage of reserve automatic input while maintaining the required level of charge of accumulator batteries.

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Description

The invention relates to the field of electric power and can be used for uninterrupted power supply for responsible consumers both in the presence and absence of a centralized power supply system.

A device for uninterrupted power supply of responsible consumers is known (patent RU No. 2321936, published April 10, 2008), connected to a three-phase network, containing a generator, a three-phase rectifier, an inverter, DC and AC buses. The rectifier and the inverter are connected in series through the DC bus and form an isolation block with the power system, which is connected in parallel with the generator to the alternating current bus, from which non-responsive and directly responsible consumers of power supply are fed through automatic shutdown means.

The disadvantages are the dependence on external power supply and the continuity of the generator.

A device for emergency power supply of a responsible consumer is known (patent RU No. 201343, publ. 05/30/1994), in which the solution to the problem of voltage regulation during the run-out of the electric motor is carried out by connecting additional capacitor banks using thyristor switches, for which zero organs, voltage transformer, phase-shifting units, single-vibrators and logical elements "AND". Each phase of the battery of additional capacitors is divided into sections, and each section of the capacitors is equipped with a logical element "And" and a thyristor key. This ensures the absence of switching overvoltages when connecting sections of additional capacitors.

The disadvantages are the dependence on external power supply, the continuity of the generator and a large number of capacitors.

A known uninterruptible power supply system (patent RU No. 2071626, publ. 10.01.1997), containing n-single-phase synchronous AC sources, which are connected through a unidirectional AC element to the load. Each unidirectional element is made in the form of four unidirectional electric keys of two types. Each two different types of switches are connected in parallel and connected between one of the poles of the source and the load, their control inputs are connected to the other pole of the source. This eliminates the reverse transfer of energy from the load to the source when one of the sources is disconnected or fails.

The disadvantage is the presence of several AC sources.

A device for guaranteed power supply is known (patent RU No. 2481688, publ.), Adopted as a prototype connected to a gas piston autonomous power plant, containing a backup diesel generator, an isolation unit with an energy system consisting of a rectifier connected via a DC bus to an uninterruptible power supply, or an electric energy storage device in the form of a storage battery and an inverter, as well as a switch used to connect an autonomous power station to an AC bus; a switch used to connect a backup diesel generator; means for automatically shutting off disconnected power consumers of varying degrees of responsibility and responsible consumers directly connected to alternating current buses and a control system designed to coordinate the operation of a gas piston power plant, a backup diesel generator and elements of the power decoupling unit through high-speed thyristor switches providing synchronized switching of various sources of electrical energy with acceptable phase angle Bani between their output voltages.

The disadvantage of this device is the inability to recharge the batteries from the backup generator. Since it may be necessary to switch back from the backup generator to the main source of power supply, and the battery charge level may not be sufficient to maintain the operation of non-disconnect consumers during switching and phase synchronization of the output voltage of the generators, and in the event of a failure of both generators, for trouble-free completion of the process.

The technical result is the provision of a two-stage automatic input reserve while maintaining the required charge level of the batteries, and thereby providing uninterrupted power supply to responsible consumers.

The technical result is achieved by the fact that the uninterruptible power supply device connected to the autonomous power plant contains a backup generator, and also has a charger as part of the decoupling unit with the power system, connected through a rectifier and a switch with alternating current buses of the backup generator, thereby ensuring the required level of battery charge batteries for powering non-disconnect consumers during subsequent switching between generators.

An uninterruptible power supply device is illustrated in FIG. 1, where:

1 - autonomous power station;

2 - backup generator;

3 - block interchange with the power system;

4 - switch for connecting the rectifier to the bus of an autonomous power station;

5 - rectifier;

6 - charger;

7 - battery;

8 - switch connecting the battery to the inverter, as well as providing power from the batteries and the rectifier;

9 - inverter;

10 - switch for connecting the inverter to the main AC bus;

11 - thyristor switch;

12 - switch for connecting an autonomous power station to the main AC bus;

13 - thyristor device for automatic input of a reserve;

14 - means for automatically shutting off completely disconnected consumers;

15 - completely disconnected consumers;

16 - means for automatically disconnecting partially disconnected consumers;

17 - partially disconnected consumers;

18 - non-disconnect consumers;

19 - control system;

20 - switch used to connect a backup generator;

21 - thyristor device for automatic input of a reserve;

22 - switch connecting the output bus AC alternating generator to the rectifier;

23 - AC bus autonomous power station;

24 - AC bus backup generator;

25 - DC bus connecting the rectifier with the switch for connecting the battery to the inverter;

26 - main bus AC.

An uninterrupted power supply device consists of the following elements: an autonomous power station 1 is connected to an isolation unit with a power system 3, which consists of a switch 4 for connecting a rectifier to an alternating current bus 23 of an autonomous power station, a rectifier 5, a charger 6, a battery 7, a switch 8 for connecting a battery batteries to the inverter 9, the inverter 9 and the DC bus 25. Block 3 isolation from the power system through the switch 10 to connect the converted energy of the battery switches and switches 4 and 12 are connected to the main AC bus 26. Parallel to the switch 12 is connected a thyristor device for automatic input of the reserve 13, and parallel to the switch 10 is connected to a thyristor switch 11. To the main bus of the alternating current 26 using means 14 for automatically disconnecting completely disconnected consumers are connected fully disconnected consumers 15 (first stage of automatic unloading) and using means 16 for automatically shutting off partially disconnected consumers, partially connected tklyuchaemye consumers 17 (second stage automatic unloading). Non-disconnectable consumers 18 are directly connected to the main AC bus 26 and a backup generator 2 is connected via a switch 20. A thyristor device for automatic input of a reserve 21 is connected in parallel with the switch 20. The control system 19 is connected to means 14 for automatically switching off completely disconnected consumers, for means 16 for automatically switching off partially switched off consumers, switch 8, thyristor devices for automatic input reserve 13 and 21, thyristor switch 11, switch 22 for connecting the alternating current bus of the backup generator 2 to the rectifier 5, an autonomous power station 1.

The uninterrupted power supply of non-disconnect consumers is as follows. In normal mode, power supply to all consumers is carried out by autonomous power station 1. In an emergency operation of autonomous power station 1, during start-up and reaching the rated mode of standby generator 2, power supply to non-disconnected consumers is provided by the energy output from the battery. To eliminate the power shortage of the backup generator 2, consumers are switched off one by one in accordance with the unloading stages. Switching algorithm between the three power sources and matching them to work together incorporated in the control system 19. At startup standby generator 2 and its subsequent connection responsible consumers receive power from the battery 7. Synchronization between the same _and the voltages U of the inverter outlet 9 and a backup generator _WG U 2 is provided using blocks of a thyristor switch 11 and a thyristor automatic input of a reserve 21. The ability to connect a backup generator 2 to the main bus e AC 26 there is no occurrence of an overcurrent, if the angle of the phase mismatch between the respective voltages are not greater than 30 electrical degrees. Otherwise, the currents increase up to twice if the backup generator 2 is connected to the main alternating current bus 26 at the moment the phases are in antiphase, which will lead to the operation of relay protection and automation equipment with the occurrence of an interruption in power supply, leading to disruption of the technological process. To connect a backup generator 2 without phase disagreement between its output voltage and the output voltage of the inverter 9, a thyristor automatic transfer switch 21 is connected in parallel with the switch 20. The thyristor automatic transfer switch is designed to maintain non-disconnected consumers in operation in the event of an emergency - loss of supply voltage on one from inputs, by switching as quickly as possible to serviceable input without the occurrence of overcurrents. Optimization of transients is provided by synchronizing the moment of turning on the thyristor device for automatic input of the reserve with the angle of the phase difference of the voltages at the terminals of the generator with a voltage at the inverter output ranging from 0 to 30 electrical degrees. The thyristor device for automatic input of the reserve 21 allows you to synchronously switch the power supply to the standby generator with a phase misalignment angle of no more than 30 electrical degrees, as well as to control the voltage recovery in the main network with automatic switching to the normal power supply circuit after voltage recovery on the faulty input. When restoring the normal mode from the battery power supply 1 is also a danger of increasing the angle between the same phase mismatch _NPP U voltages on the output power of battery 1 and backup generator _WG U 2. To prevent this, the switch 12 is connected parallel to the thyristor unit automatic transfer switch 13. After the elimination of the emergency thyristor switch 11 is activated, connected in parallel with the switch 10, to exclude the possibility of energy flow ie the inverter 9 to the network. The control system 19 controls the joint operation of the thyristor devices for automatic input of the reserve 13 and 21 and the thyristor switch 11 to ensure synchronization of commissioning of various sources of power supply.

But during the emergency mode, the energy supplied by the batteries 7 to the power of non-disconnect consumers 18 when switching from an autonomous power station 1 to a backup generator 2 must be restored to the nominal value, which is achieved due to the presence of a switch 22 connecting AC buses 24 of the backup generator 2 to the unit rectifier 5. The charger 6 provides and maintains the required level of charge on the batteries 7, and the switch 8 does not allow power to flow into the inverter 9, and also provides constant power supply to the control system 19. In the event of a malfunction on the batteries 7, power is provided to the control system via DC buses 25 connecting the switch 8 and the rectifier 5.

Thus, the device provides uninterrupted power supply to non-disconnected consumers with an appropriate level of synchronization of the output voltages of various sources of electricity.

Moreover, the power of the batteries should be selected from the constant power supply of the control system while maintaining the nominal operating mode of the non-disconnected consumers for the period of switching between the autonomous power station and the backup generator, and if it is not possible to start the reserve, the battery capacity should ensure trouble-free completion of technological processes on non-disconnected consumers.

Claims (1)

An uninterruptible power supply device, including a standby generator connected to an autonomous power station, an interconnector with a power system, a switch connecting the specified unit to the main AC bus, a switch for connecting the autonomous power station to the main AC bus, a switch for connecting the backup generator to the main AC bus current, means of automatic shutdown of fully and partially disconnected, as well as non-disconnected consumers, control system, under connected to an autonomous power plant, a backup generator, the main AC bus, from which the consumers are completely and partially disconnected, as well as non-disconnectable consumers, which are powered by means of automatic power shut-off, and the autonomous power station is connected to the AC bus both through a switch and through an isolation unit with the power system , thyristor devices for automatic input of a reserve, one of which is connected in parallel with the switch for connecting an autonomous power station to the main bus not AC, but the other is connected in parallel to the switch for connecting the backup generator to the main AC bus, and a thyristor switch connected in parallel to the switch for connecting the inverter to the main AC bus, the control system outputs connected to the inputs of the thyristor devices for automatic input of the reserve and thyristor switch characterized in that the isolation unit with the power system is additionally equipped with a charger connected in series through a rectifier with a switch that is connected in series with the alternating current buses of the backup generator, as well as a switch for connecting the battery to the inverter and DC buses connecting the rectifier and the switch for connecting the batteries.

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