KR101673494B1 - Apparatus for controlling stand alone - Google Patents

Apparatus for controlling stand alone Download PDF

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Publication number
KR101673494B1
KR101673494B1 KR1020150126142A KR20150126142A KR101673494B1 KR 101673494 B1 KR101673494 B1 KR 101673494B1 KR 1020150126142 A KR1020150126142 A KR 1020150126142A KR 20150126142 A KR20150126142 A KR 20150126142A KR 101673494 B1 KR101673494 B1 KR 101673494B1
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KR
South Korea
Prior art keywords
master
generator
distributed
power
pcs
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KR1020150126142A
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Korean (ko)
Inventor
이준기
엄주경
주성남
임정민
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(주)인텍에프에이
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/40—Synchronising a generator for connection to a network or to another generator
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/12—Monitoring or controlling equipment for energy generation units, e.g. distributed energy generation [DER] or load-side generation
    • Y04S10/123—Monitoring or controlling equipment for energy generation units, e.g. distributed energy generation [DER] or load-side generation the energy generation units being or involving renewable energy sources

Abstract

An embodiment of the present invention includes: a master generator generating power of an independent grid; a distributed generator connected in parallel with the master generator; a master circuit breaker delivering or shutting off the generated power of the master generator to an independent grid power system; a distributed circuit breaker delivering or shutting off the generated power of the distributed generator to the independent grid power system; a master PCS connected with the master generator to control the shutoff of the master circuit breaker; and a distributed PCS connected with the distributed generator to control the shutoff of the distributed circuit breaker, and inducing the generated power of the distributed generator to be inserted into the grid power system by coming into contact with the distributed circuit breaker when the generated power of the master generator is delivered to the grid power system by coming into contact with the master circuit breaker. Therefore, the present invention is capable of suppressing an overcurrent.

Description

[0001] Apparatus for controlling stand alone [

The present invention relates to an independent self-standing operation control device, and more particularly, to an apparatus for controlling independent self-standing operation when power generated from a distributed generator is coupled to an independent grid load.

Recently, due to problems such as exhaustion of fossil energy and environmental pollution, much attention has been focused on the development using alternative energy.

In the case of a system applied to an independent grid in a book area or a specific area, for example, a distributed generator such as an energy storage system may be fed into the master generator. The master generator is a generator that forms the voltage and frequency of the independent grid in a stand-alone mode using an energy storage device such as a battery. If the capacity of the master generator is sufficient, the load may cause imbalance, And the influence generated when feeding is minimized.

For this purpose, the master PCS (Master Power Conditioning System) control algorithm is secured. However, in general, when an independent power source is made using a power conversion device, the system may be shut down due to an inrush current or an initial charge current at the time of starting the load. In the case of 3-phase PCS, there is a limitation in solving the phase-to-phase voltage imbalance of the 3-phase 4-wire independent grid. There is also a problem when interfacing with a master generator of a diesel generator or other independent power supply power converter.

If a generator such as a diesel generator becomes a master generator, if the master power conditioning system is changed to a grid connection mode to charge or discharge the battery, the master PCS 110 may operate as a general grid-connected PCS 110 . On the contrary, when the master PCS becomes the master generator, if the inertia load such as the diesel generator is attached to the distributed generator, if the master PCS is larger than the generator capacity, it is possible to operate by putting it in parallel. However, the controller of the diesel generator is inertial, There is a delay element such as injection injection, so it can not follow the control of the PCS

Therefore, the problem of difficulty in bottling the diesel generator occurs. In addition, the voltage, phase, and frequency deviation due to load imbalance are factors affecting the feeding of distributed generators.

Korean Patent Publication No. 10-2011-0101564

An object of the present invention is to provide an apparatus for controlling independent self-standing operation when power generated by a distributed generator is coupled to an independent grid load. The technical problem of the present invention is to minimize the voltage imbalance of the master PCS generating the power supply of the independent grid and to suppress the overcurrent generated at the time of start-up, so that the power generation of other kinds of generated power is prevented from occurring at the time of bottling.

An embodiment of the present invention is directed to a master generator for generating power for an independent grid; A distributed generator connected in parallel to the master generator; A master breaker for causing or blocking the generated power of the master generator to the independent grid power system; A distributed circuit breaker for causing or blocking generated electric power of the distributed generator to be transmitted to the independent grid electric power system; A master PCS connected to the master generator to perform shutdown control of the master breaker; And the distributed circuit breaker is connected to the distributed generator to perform shutoff control of the distributed circuit breaker, and when the master circuit breaker is brought into contact and the generated power of the master generator is transmitted to the independent grid power system, There is provided an independent freestanding operation control device including a distributed PCS that causes generated power of a generator to be simultaneously fed into a grid power system.

The master PCS detects the input of the distributed generator by using the auxiliary contact of the distributed power source circuit breaker and changes the mode from the fixed voltage fixed frequency (CVCF) mode to the variable voltage variable frequency (VVVF) mode to start the synchronization, To the fixed voltage fixed frequency (CVCF) mode.

The distributed PCS has a power control capacity smaller than that of the master PCS.

The master circuit breaker and the distributed circuit breaker may be a magnetic circuit breaker (MCB) or a vacuum circuit breaker (VCB).

A detector for detecting voltage, current, and frequency of the independent grid; And a power calculation unit calculating power using information of the detection unit.

According to the embodiment of the present invention, stable power supply of the master PCS can be secured and load imbalance can be minimized, the overcurrent generated during start-up can be suppressed, the voltage rise due to the feeding and removing of the load can be suppressed, Power operation can be ensured.

1 is a block diagram of a configuration of an independent self-sustained operation control apparatus according to an embodiment of the present invention;
FIG. 2 is a diagram showing the voltage and frequency command value judgment conditions of the master PCS. FIG.
Figure 3 illustrates an example of an algorithm for performing current control in a master PCS and a distributed PCS.
4 is a diagram showing an example of an algorithm for performing voltage control in a master PCS and a distributed PCS;

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to achieve them, will be apparent from the following detailed description of embodiments thereof taken in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of the invention to those skilled in the art. And the present invention is only defined by the scope of the claims. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It is to be understood that the present invention is not limited to the embodiments disclosed herein but may be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein. It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

FIG. 1 is a block diagram of an independent self-sustained operation control apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating voltage and frequency command value judgment conditions of a master PCS.

If a generator such as a diesel becomes the master generator 100, the master PCS 110 is changed to a grid connection mode to charge the battery or discharge it to the independent grid. The introduction of grid-connected generators, such as general solar or wind power PCS, is not a problem in CVS mode PCS. However, if an inertial load such as a diesel generator is attached to the master PCS 110, if the master PCS 110 is larger than the capacity of the master generator 100, Because of delay factors such as injecting fuel, the generator can not follow the control of PCS in fixed voltage and constant frequency (CVCF) mode PCS.

Also, mode switching is selected by using the auxiliary contact of the breaker of the output of the master generator such as diesel generator to detect the feed-in of the generator. When the master PCS 110 is in the CVCF operation and a power source having the same voltage and frequency as the diesel generator is applied, the voltage and frequency of the diesel generator are monitored by the VVVF operation. Synchronization induces bottlenecks without power failure. That is, by using the auxiliary contact of the diesel generator circuit breaker, the variation of the voltage and the frequency is increased, and when the synchronization is completed, the variation is reduced.

The other distributed generators 200 must be capable of operating below the capacity of the master PCS 110. [ Because the master PCS 110 has to bear all the energy when the other distributed generators 200 are stopped (in the discharge mode), the other distributed generators 200 must perform the control while monitoring the required capacity. This will be described in detail below.

The present invention relates to an independent self-sustained operation control device for a parallel operation of a grid-connected distributed power supply, comprising a master generator 100, a distributed generator 200, a master breaker 120, a distributed circuit breaker 220, , And a distributed PCS 210. < RTI ID = 0.0 >

The master generator 100 is a stand-alone PCS equipped with a generator, such as a diesel generator, that provides power to the independent grid power system using fuel or a chargeable and dischargeable battery system.

The distributed generator 200 is a grid-connected generator that generates electricity by using alternate energy on the earth such as a photovoltaic generating system (PV generating system), a wind power generating system, and the like. The distributed generator 200 is connected in parallel to the master generator 100 so that the distributed power generated by the distributed generator 200 can be fed into the independent grid power system with the master power generated by the master generator 100 .

The master breaker 120 is a circuit breaker that allows or blocks the generated power of the master generator 100 to the independent grid power system.

The distributed circuit breaker 220 is a circuit breaker that transmits or cuts the generated power of the distributed generator 200 to the independent grid power system.

That is, the switching device is composed of a main component CB of a substation, a disconnecting switch (DS), an earthing switch (ES), a lightning arrester, and a main bus . Here, the breaker is a type of power switching device that can open and close an abnormal state, in particular, a contact or a ground line, in addition to a normal-state electric wire. The breaker may be a vacuum circuit breaker (VCB: Vacuum Circuit A breaker, and a magnetic circuit breaker (MCB).

The master PCS 110 interworks with other distributed PCSs 210 to sequentially perform frequency and load distribution.

3 is a diagram illustrating an example of an algorithm for performing current control in the master PCS 110 and the distributed PCS 210. In FIG.

In order to control the voltage command value (Vde *, Vqe *), it is possible to eliminate phase imbalance by controlling each phase in the case of 3-phase 4-wire type PCS, but it is difficult to control each phase in 3-phase PCS. Thereby minimizing the voltage imbalance. In other words, the three-phase voltage is detected and the image minute voltage is removed. The coordinate difference is converted into the normalized minus voltage and the minus frequency of the double frequency of the fundamental frequency. As shown in Fig. 4, the PI control is performed using the difference between the normal and reverse phase currents and the normal phase and the reverse phase currents at twice the fundamental frequency, and the overcurrent suppression (Ide *, Iqe * By passing through the controller, the final PWM reference value can be generated to eliminate the voltage imbalance.

Accordingly, the master PCS 110 and the distributed PCS 210 can detect a normal component and a reverse phase voltage to eliminate a load imbalance, and a stable power can be generated by adding a current suppression controller and a voltage suppression controller.

The distributed PCS (Decentralized Power Conditioning System) 210 is a power management device that performs power control on the generated power of the distributed generator 200.

Each of the master PCS 110 and the distributed PCS 210 performs power control on the generated power of the master generator 100. [ That is, the master PCS 110 is connected to the master generator 100 and performs shutdown control of the master breaker 120. The master PCS 110 contacts the master breaker 120 so that the generated power of the master generator 100 is transferred to the independent grid power system or the master breaker 120 is opened to generate the generated power of the master generator 100 To the grid power system.

Likewise, the distributed PCS 210 is connected to the distributed generators 200 to perform shutdown control of the distributed circuit breaker 220. The distributed PCS 210 contacts the distributed circuit breaker 220 so that the generated power of the distributed generator 200 is transferred to the independent grid power system or the distributed circuit breaker 220 is opened, It is blocked from being fed into the independent grid power system and transmitted.

If an inertial load such as a diesel generator is attached to the master PCS 110, if the master PCS 110 is larger than the capacity of the generator, it is possible to operate in parallel by inserting the inertial load into the master PCS 110. However, the controller of the diesel generator is inertial, There is a delay element, such as the PCS can not follow the control. Also, it is possible to change the magnitude and frequency of the output voltage of the master PCS 110 in order to input the diesel generator, but this makes it difficult to operate the other generators.

In order to solve such a problem at the time of the bottleneck of the distributed power, the distributed PCS 210 of the present invention is configured such that, at the moment when the master breaker 120 is contacted and the generated power of the master generator 100 is transmitted to the grid power system, So that the generated power of the distributed generator 200 is fed into the grid power system at the same time.

When the master circuit breaker 120 is implemented as a vacuum circuit breaker, the moment the stator and the mover, which open and close the current conduction in the vacuum circuit breaker, are in contact with each other and the generated power of the master generator 100 is transmitted to the grid power system , And the distributed PCS 210 make contact with the distributed circuit breaker 220 so that the generated power of the distributed generator 200 is fed into the grid power system at the same time.

When the contact point is detected, the detection signal is transmitted to the distributed PCS 210. The distributed PCS 210 contacts the distributed circuit breaker 220 to contact the distributed generator 200 to generate electric power of the dispersed electric power generator 200 at the same time .

Meanwhile, the master PCS 110 and the distributed PCS 210 cooperate with each other to sequentially perform frequency and load distribution to perform synchronization control. The synchronization control first performs synchronous control on the frequency, and then sequentially performs synchronous control on the load.

In order to supply two or more generators in parallel, the parallel operation condition is required, the phases of the electromotive force must be the same, the electromotive force should be the same, the electromotive force waveform should be the same, and the direction of the phase rotation must be the same.

When the phase difference between the generator's electromotive force is small, the synchronization current flows and the generator with the slow phase is accelerated. The generator with the high phase is decelerated and eventually synchronized. If the phase difference is too large, excessive synchronization current will cause the generator to be damaged or out of synchronization.

If the frequency of the power generation period is not the same, the phases can not coincide with each other, so that the synchronous operation becomes impossible.

If the waveforms of the respective generators are not the same as the sinusoidal waves, harmonic circulation current flows through the generator due to the harmonic voltage included in the electromotive force to overheat the generator.

Also, the direction of the phase rotation must be the same, but if the overturns of the generators do not coincide, the generator will stop or become out of order or bottled.

For the reasons described above, the master PCS 110 and the distributed PCS 210 interlock with each other to sequentially perform frequency and load distribution and perform synchronization control.

The master breaker 120 is brought into contact with the master generator 100 at a point of time when synchronization between the generated power and the dispersed power of the master generator 100 is completed and the generated power of the master generator 100 is transmitted to the independent grid power system.

The power control of the master generator 100 is performed while the power of the master generator 100 is synchronized with the generated power of the master generator 100 and the power of the variable voltage variable frequency VVVF Increase the voltage and frequency variations and then perform a power control (CVCF) that reduces if stabilized.

It is an uninterruptible power supply means to prevent the power failure due to voltage fluctuation, frequency fluctuation, instantaneous power failure, transient voltage and so on when using fixed voltage high frequency (CVCF), general power or spare power, and always supply stable power.

The master generator 100 operates in a state of variable voltage variable frequency (VVVF) mode and synchronizes. At the completion of the synchronization, the mode is switched to the fixed voltage fixed frequency (CVCF) mode, and stable mode switching is performed. The determination as to when the synchronization is completed can be determined by a change in the power of the master PCS. In this case, it is possible to prevent power failure at the time of bottling when the distributed power is fed.

On the other hand, the distributed PCS 210 preferably has a power control capacity smaller than the power control capacity provided by the master PCS 110. [ This is because the other distributed generators 200 must perform control while monitoring the necessary capacity since the master PCS 110 must bear all the energy when the other distributed generators 200 are stopped (in the discharge mode) .

The embodiments of the present invention described above are selected and presented in order to facilitate the understanding of those skilled in the art from a variety of possible examples. The technical idea of the present invention is not necessarily limited to or limited to these embodiments Various changes, modifications, and other equivalent embodiments are possible without departing from the spirit of the present invention.

100: master generator
110: master PCS
120: master breaker
200: Distributed generator
210: Distributed PCS
220: Distributed circuit breaker

Claims (5)

A master generator for generating power for an independent grid;
A distributed generator connected in parallel to the master generator;
A master breaker for causing or blocking the generated power of the master generator to the independent grid power system;
A distributed circuit breaker for causing or blocking generated electric power of the distributed generator to be transmitted to the independent grid electric power system;
A master PCS connected to the master generator to perform shutdown control of the master breaker; And
The distributed circuit breaker is connected to the distributed generator and performs shutoff control of the distributed circuit breaker and contacts the distributed circuit breaker at a moment when the master circuit breaker is brought into contact and the generated power of the master generator is transmitted to the independent grid power system, And a distributed PCS that allows the generated power of the grid power system to be simultaneously fed into the grid power system,
The master PCS and the distributed PCS operate in synchronization with each other in order to perform frequency and load distribution,
The master PCS,
Distributed Generator The input of the distributed generator is detected by using the auxiliary contact of the breaker and the synchronization is started by changing from the fixed voltage fixed frequency (CVCF) mode to the variable voltage variable frequency (VVVF) mode. Changes to the fixed frequency (CVCF) mode,
The determination as to when the synchronization is completed is determined by a change in the power of the master PCS,
Wherein the master PCS and the distributed PCS further include a current suppression controller and a voltage suppression controller for detecting load imbalance by detecting a normal component and a reverse phase voltage.
delete The method of claim 1,
And the power control capacity of the master PCS is smaller than the power control capacity of the master PCS.
The power supply apparatus according to claim 1,
(MCB) or a vacuum circuit breaker (VCB).
The method according to claim 1,
A detector for detecting voltage, current, and frequency of the independent grid; And
And a power calculation unit for calculating power using information of the detection unit.

KR1020150126142A 2015-09-07 2015-09-07 Apparatus for controlling stand alone KR101673494B1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20200066759A (en) 2018-12-03 2020-06-11 (주)위 에너지 Control system for Gen-Invertor-Grid Switch and the method thereof
KR20230161903A (en) * 2022-05-19 2023-11-28 파이온일렉트릭 주식회사 Inertial output auxiliary control device linked to synchronous condenser
KR20230161905A (en) * 2022-05-19 2023-11-28 파이온일렉트릭 주식회사 System for hybrid grid forming of synchronous machine and static frequency converter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003264932A (en) * 2002-03-08 2003-09-19 Osaka Gas Co Ltd High-speed current limiting and interrupting device for electric power system interconnection
KR20110101564A (en) 2010-03-09 2011-09-16 김정호 Control system of load power linked with the computer and control method thereof
KR101431429B1 (en) * 2014-04-10 2014-08-18 사단법인 한국선급 Electric Power Control system for Integration of various ship electric power Source having fuel cell system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003264932A (en) * 2002-03-08 2003-09-19 Osaka Gas Co Ltd High-speed current limiting and interrupting device for electric power system interconnection
KR20110101564A (en) 2010-03-09 2011-09-16 김정호 Control system of load power linked with the computer and control method thereof
KR101431429B1 (en) * 2014-04-10 2014-08-18 사단법인 한국선급 Electric Power Control system for Integration of various ship electric power Source having fuel cell system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20200066759A (en) 2018-12-03 2020-06-11 (주)위 에너지 Control system for Gen-Invertor-Grid Switch and the method thereof
KR20230161903A (en) * 2022-05-19 2023-11-28 파이온일렉트릭 주식회사 Inertial output auxiliary control device linked to synchronous condenser
KR20230161905A (en) * 2022-05-19 2023-11-28 파이온일렉트릭 주식회사 System for hybrid grid forming of synchronous machine and static frequency converter
KR102640389B1 (en) 2022-05-19 2024-02-27 파이온일렉트릭 주식회사 Inertial output auxiliary control device linked to synchronous condenser
KR102640399B1 (en) 2022-05-19 2024-02-27 파이온일렉트릭 주식회사 System for hybrid grid forming of synchronous machine and static frequency converter

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