CN113629718A - Dual-power voltage stabilization control system - Google Patents
Dual-power voltage stabilization control system Download PDFInfo
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- CN113629718A CN113629718A CN202110461926.0A CN202110461926A CN113629718A CN 113629718 A CN113629718 A CN 113629718A CN 202110461926 A CN202110461926 A CN 202110461926A CN 113629718 A CN113629718 A CN 113629718A
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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
- H02J3/12—Circuit arrangements for AC mains or AC distribution networks for adjusting voltage in AC networks by changing a characteristic of the network load
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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
- H02J3/007—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources
- H02J3/0073—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources for providing alternative feeding paths between load and source when the main path fails, e.g. transformers, busbars
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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
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
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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
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
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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
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other DC sources, e.g. providing buffering
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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
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other DC sources, e.g. providing buffering
- H02J7/345—Parallel operation in networks using both storage and other DC sources, e.g. providing buffering using capacitors as storage or buffering devices
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Abstract
本发明公开了一种双电源电压稳定控制系统，包括：连接电网与负荷的母线、与母线并联设置的储能系统和维修旁路，以及投切控制系统；母线上沿电网至负荷方向依次设有第一开断装置、静态开关装置和第二开断装置，维修旁路上设有第三开断装置；储能系统包括至少一个储能装置、整流逆变单元、第二隔离装置和充电装置；投切控制系统用于：对电网的电压实时采样，并判断电网的电压是否发生波动；当判断电网的电压稳定时，使电网通过母线为负荷供电，同时充电装置和整流逆变单元为储能装置充电；当判断电网的电压出现波动时，整流逆变单元将储能装置输出的直流电转换为交流电后为负荷供电。有效治理电压暂降、电压暂升、短时中断等问题。
The invention discloses a dual power supply voltage stability control system, comprising: a busbar connecting a power grid and a load, an energy storage system and a maintenance bypass arranged in parallel with the busbar, and a switching control system; There are a first breaking device, a static switching device and a second breaking device, and a third breaking device is arranged on the maintenance bypass; the energy storage system includes at least one energy storage device, a rectifier inverter unit, a second isolation device and a charging device ;The switching control system is used to: sample the voltage of the power grid in real time, and judge whether the voltage of the power grid fluctuates; when the voltage of the power grid is judged to be stable, make the power grid supply power to the load through the bus, and at the same time the charging device and the rectifier and inverter unit are used for storage. When it is judged that the voltage of the power grid fluctuates, the rectifier and inverter unit converts the DC power output by the energy storage device into AC power and supplies power to the load. Effectively manage problems such as voltage sag, voltage swell, and short-term interruption.
Description
Technical Field
The invention relates to the technical field of power supply voltage stabilization control of a power grid, in particular to a dual-power-supply voltage stabilization control system.
Background
At present, the existing online voltage stabilization control system mainly comprises a voltage source inverter, a bypass and a compensation transformer connected in series between a power supply grid and a load. Once the voltage deviates from the set value, the IGBT inverter is immediately controlled to add proper compensation voltage into the main loop through the compensation transformer connected in series, and the voltage at the output end can be quickly regulated to the set value, so that the influence of voltage sag at the output end of the power grid on a load is eliminated.
However, this technique has the following problems:
1. because the compensation energy is provided by the power grid, the deep voltage sag cannot be managed;
2. the secondary side of the compensation transformer is directly connected to a power grid, and the installation is difficult.
Disclosure of Invention
The invention aims to provide a dual-power-supply voltage stabilization control system which effectively solves the problems of voltage sag, voltage rise, short-time interruption and the like and improves the stability, reliability and switching efficiency of a power supply system.
In order to achieve the above object, the present invention provides a dual power supply voltage stabilization control system, including:
the system comprises a bus for connecting a power grid and a load, an energy storage system and a maintenance bypass which are arranged in parallel with the bus, and a switching control system;
one end of the bus is connected with the power grid through a first isolating device, and the other end of the bus is connected with the load;
a first cut-off device, a static switch device and a second cut-off device are sequentially arranged on the bus along the direction from the power grid to the load, and a third cut-off device is arranged on the maintenance bypass;
the energy storage system comprises at least one energy storage device, a rectification inversion unit, a second isolation device and a charging device, wherein the energy storage device, the rectification inversion unit and the isolation device are sequentially connected in series and then are connected with a bus between the static switch device and the second switching-on/off device;
one end of the charging device is connected with a bus between the first cut-off device and the static switch device, and the other end of the charging device is connected with the energy storage device;
the switching control system is used for:
sampling the voltage of the power grid in real time, and judging whether the voltage of the power grid fluctuates or not;
when the voltage of the power grid is judged to be stable, the first switching-off device, the static switch device and the second switching-off device are controlled to be switched on, and the third switching-off device is controlled to be switched off, so that the power grid supplies power to the load through the bus, and meanwhile, the charging device and the rectification inversion unit charge the energy storage device;
and when the voltage of the power grid is judged to fluctuate, the static switch device is controlled to be switched off, and the rectification inversion unit is controlled to convert the direct current output by the energy storage device into alternating current to supply power to the load.
Optionally, the switching control system is further configured to:
when the system needs maintenance and detection, the first cut-off device, the static switch device and the second cut-off device are controlled to be turned off, and the third cut-off device is controlled to be turned on, so that the power grid supplies power to the load through the maintenance bypass.
Optionally, the first and second cut-off devices are circuit breakers or contactors;
the static switch device is a silicon controlled static switch;
the third switching device is a contactor or a load switch.
Optionally, a bus at the thyristor static switch is provided with a standby bypass connected with the thyristor static switch in parallel, and a circuit breaker or a contactor is arranged on the standby bypass.
Optionally, the energy storage device comprises at least one of a supercapacitor and a lithium ion battery.
Optionally, the energy storage device is a super capacitor, and the super capacitor is arranged in the capacitor cabinet;
the capacitor box adopts a modular design, and a plurality of capacitor boxes can be spliced according to the discharge time.
Optionally, the other end of the bus is connected to the load through a third isolation device;
the first isolating device, the second isolating device and the third isolating device are pure copper or enameled aluminum transformers;
the transformer is a delta/Z type isolation transformer, and the insulation grade of the transformer is H.
Optionally, the rectified inversion unit is a fully-controlled IGBT power device.
Optionally, the switching control system samples the voltage of the power grid in real time, and determining whether the voltage of the power grid fluctuates includes:
sampling the instantaneous voltage value of the power grid in real time and comparing the instantaneous voltage value with a set threshold value to judge whether the voltage of the power grid fluctuates or not; wherein, the sampling frequency is 6.4KHz, and the voltage drop detection time is 1.5 ms;
meanwhile, a dq coordinate detection method is adopted to convert the three-line alternating voltage sampled in real time into a direct current effective voltage value with equal amplitude, and the direct current effective voltage value is compared with a set threshold value to judge whether the voltage of the power grid fluctuates; wherein the maximum detection time is 1.25 ms;
and when the instantaneous voltage values sampled in a plurality of continuous sampling periods are larger than or smaller than the set threshold value and the effective voltage values are continuously detected for a plurality of times to be larger than or smaller than the set threshold value, judging that the voltage fluctuation effective event occurs in the power grid, and starting the subsequent switching work.
Optionally, the system further comprises a monitoring platform, wherein the monitoring platform comprises a dynamic reactive power compensation function module, an active filtering function module, a communication interface and a human-computer interaction interface.
The invention has the beneficial effects that:
through setting up in the parallelly connected energy storage system of generating line as voltage compensation system, whether the voltage of electric wire netting is taken place undulantly and is judged to the voltage real-time sampling of electric wire netting based on switching control system simultaneously, when judging when the voltage of electric wire netting is stable, control cut-off device makes the electric wire netting passes through the generating line does the load power supply, simultaneously charging device with rectification contravariant unit does energy storage device charges, when judging when the voltage of electric wire netting appears undulantly, controls a plurality of switching device and makes rectification contravariant unit be after converting the direct current that energy storage device exported into the alternating current for the load power supply, can effectively administer problems such as voltage sag, short-term interrupt, applicable worst electric wire netting condition and simple to operate, can effectively improve power supply system's stability, reliability and switching efficiency, be applicable to semiconductor manufacturing, Petroleum and petrochemical industry, chemical industry, automobile manufacturing, precision processing, pharmacy, paper making, medical health, tobacco, metallurgy, steel, printing, glass, textile industry and the like which have high requirements on the quality of electric energy.
The apparatus of the present invention has other features and advantages which will be apparent from or are set forth in detail in the accompanying drawings and the following detailed description, which are incorporated herein, and which together serve to explain certain principles of the invention.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings, in which like reference numerals generally represent like parts.
Fig. 1 shows a schematic diagram of a dual power supply voltage stabilization control system according to an embodiment of the invention.
Fig. 2 shows a schematic diagram of a power supply mode of a grid voltage in a dual power supply voltage stabilization control system according to an embodiment of the invention.
Fig. 3 is a schematic diagram illustrating a power supply mode of an energy storage device in a dual power supply voltage stabilization control system according to an embodiment of the invention.
Fig. 4 shows a schematic diagram of a delta/Z output isolation transformer in a dual power supply voltage stabilization control system according to an embodiment of the invention.
Fig. 5 shows a graph of on-load switching when the grid voltage sags by 50% in a dual supply voltage stabilization control system according to an embodiment of the present invention.
Fig. 6 shows a graph of on-load switching when the grid voltage sags by 90% in a dual supply voltage stabilization control system according to an embodiment of the present invention.
In the figure:
1-a power grid, 2-a load, 3-a first isolation device, 4-a third isolation device, 5-a second isolation device, 6-a maintenance bypass, 7-a first cut-off device, 8-a static switch device, 9-a second cut-off device, 10-a third cut-off device, 11-an energy storage device, 12-a rectification inversion unit and 13-a charging device.
Detailed Description
The invention will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Fig. 1 shows a schematic diagram of a dual power supply voltage stabilization control system according to an embodiment of the invention.
As shown in fig. 1-3, a dual-power voltage stabilization control system includes:
the system comprises a bus for connecting a power grid 1 and a load 2, an energy storage system and a maintenance bypass 6 which are arranged in parallel with the bus, and a switching control system;
one end of the bus is connected with the power grid 1 through a first isolating device 3, and the other end of the bus is connected with the load 2 through a second isolating device 5;
a first cut-off device 7, a static switch device 8 and a second cut-off device 9 are sequentially arranged on the bus along the direction from the power grid 1 to the load 2, and a third cut-off device 10 is arranged on the maintenance bypass 6;
the energy storage system comprises at least one energy storage device 11, a rectification and inversion unit 12, a second isolation device 5 and a charging device 13, wherein the energy storage device 11, the rectification and inversion unit 12 and the isolation device are sequentially connected in series and then are connected with a bus between the static switch device 8 and the second switching-on and switching-off device;
one end of the charging device 13 is connected with a bus between the first cut-off device 7 and the static switch device 8, and the other end is connected with the energy storage device 11;
the switching control system is used for:
sampling the voltage of the power grid 1 in real time, and judging whether the voltage of the power grid 1 fluctuates or not;
when the voltage of the power grid 1 is judged to be stable, the first cut-off device 7, the static switch device 8 and the second cut-off device are controlled to be switched on, and the third cut-off device 10 is controlled to be switched off, so that the power grid 1 supplies power to the load 2 through a bus, and meanwhile, the charging device 13 and the rectification inversion unit 12 charge the energy storage device 11;
when the voltage of the power grid 1 is judged to fluctuate, the static switch device 8 is controlled to be turned off, and the rectifying and inverting unit 12 is controlled to convert the direct current output by the energy storage device 11 into alternating current and supply power to the load 2.
Specifically, the dual power supply voltage stabilization control system of the present embodiment includes: the system comprises a cut-off device, an isolation device, a bypass device, an energy storage device 11, a rectification and inversion unit 12, a switching control system, a charging device 13 and the like. The whole system is connected with a power supply through a cut-off device, is connected with a bus load through an isolation device, and can also be separated from the power supply and the load 2 through the cut-off device and a bypass device.
Referring to fig. 2, when the power grid 1 is normal, the device is in the power grid 1 voltage supply mode;
referring to fig. 3, when abnormal conditions such as sag occur in the power grid 1, the device is in the power supply mode of the energy storage device 11.
In this embodiment, the switching control system is further configured to:
when the system needs maintenance and detection, the first cut-off device 7, the static switch device 8 and the second cut-off device 9 are controlled to be turned off, and the third cut-off device 10 is controlled to be turned on, so that the power grid 1 supplies power to the load 2 through the maintenance bypass 6.
In this embodiment, the first and second breaking devices 7 and 9 are circuit breakers or contactors;
the static switch device 8 is a silicon controlled static switch;
the third switching device 10 is a contactor or a load 2 switch.
Preferably, a standby bypass connected with the thyristor static switch in parallel is arranged on a bus at the thyristor static switch, and a circuit breaker or a contactor is arranged on the standby bypass.
Specifically, when the voltage of the power grid 1 is normal, the power grid works and closes through two circuit breakers and a silicon controlled static switch on the bus, and the power grid supplies power to the rear-end load 2 through the second isolating device 5.
The SCR is used as a static switch, a digital control technology is adopted to ensure that the switching time can meet the requirement of ms level, meanwhile, the reliability of the SCR is very high, a path can be ensured even if breakdown and burning occur, and the rated current value and the surge current value need to be considered. Ensuring that the SCR surge value is more than 1.5 times of the rated current value, and meeting the requirement of 50kA impact current by referring to related standards and 3 period requirements (60 ms);
the static switch adopts an SCR static switch, and can be configured with a breaker (or a contactor) and an SCR static bypass for parallel connection in order to provide reliability, when the SCR static switch device 8 breaks down or burns out, the breaker (or the contactor) is closed through a host control system so as to ensure that the bus voltage of the power supply continuously supplies power.
The maintenance bypass 6 is provided with a bypass device, so that when the system breaks down and is maintained, the power supply of the load 2 is continuously ensured, and the whole system is withdrawn. A contactor or a load 2 switch may be generally configured as the third switching device 10. The power supply bus bypass switching device is used for manually switching to bypass work, and improves the reliability of power utilization on the power supply bus.
In this embodiment, the energy storage device 11 includes at least one of a super capacitor and a lithium ion battery. Preferably, the energy storage device 11 is a super capacitor, and the super capacitor is arranged in the capacitor cabinet; the capacitor box adopts the modularized design, and a plurality of capacitor boxes can be spliced according to the discharge time.
Specifically, the energy storage device 11 comprises a super capacitor, a lithium ion battery or other high-power-density energy storage equipment and the like, an advanced power electronic conversion technology and a digital control technology are adopted, normally, a power supply supplies power to the load 2 through a voltage stabilization control system and charges the energy storage device 11, meanwhile, the incoming line of the power supply is monitored in real time, when the power supply fluctuates, the cut-off device is cut off in 2ms through judgment, and the mode is switched to an energy storage power supply mode.
Preferably, the energy storage device 11 employs a supercapacitor, which stores energy by means of an electrostatically polarized electrolytic solution, but its energy storage mechanism does not involve chemical reactions, which is highly reversible, with supercapacitors charging and discharging up to several tens of thousands or even millions of times.
In the specific implementation process, the energy storage super capacitor cabinet is generally composed of independent cabinet bodies, and different configurations are adopted according to different backup times. The core control unit comprises a charger, a discharge resistor and a master control unit, and is arranged in the capacitor cabinet. The output end of the capacitor cabinet is provided with an output switch, so that the on-line disconnection maintenance of the single cabinet can be realized; the capacitor cabinets are in a modular design, namely any two capacitor cabinets can directly replace each other; the online slow start function is achieved, and pre-charging of the bus capacitor of the inverter is achieved; the single capacitor equalization function and the capacitor temperature monitoring function.
In this embodiment, optionally, the other end of the bus is connected to the load 2 through a third isolation device 4; the first isolation device 3, the second isolation device 5 and the third isolation device 4 are pure copper or enameled aluminum transformers; the transformer is a delta/Z type isolation transformer, and the insulation grade of the transformer is H.
Specifically, the isolation device adopts a transformer made of pure copper or enameled aluminum, the transformer is in an H insulation grade, the isolation device mainly plays a role in electrical isolation and prevents the direct passage of a load side when an energy storage high-voltage part of the inverter fails, and meanwhile, the isolation device can be an independent TN-S system after a power bus is disconnected, so that the usability of a rear-end load 2 power supply is ensured to the maximum extent.
Preferably, referring to fig. 4, the isolation transformer adopts a unique delta/Z type isolation transformer, so that complete electrical isolation of the inverter output is realized, and the output three-phase imbalance capability is improved: the output voltage precision satisfies: less than or equal to plus or minus 1 percent (balanced load) and less than or equal to plus or minus 2 percent (unbalanced load: 0-0-100 percent and 0-100 percent); the three-phase shift asymmetry satisfies 120 ° ± 1%.
The delta/Z type isolation transformer is different from the conventional delta/Y type transformer in that the secondary windings and the primary windings of the transformer are not in one-to-one correspondence but are wound in a staggered manner (see fig. 4), that is, half of the secondary a-phase winding and half of the c-phase winding (in anti-phase) correspond to the primary a-phase winding. Thus, when the load is 100% unbalanced, it corresponds to only 50% of the primary side being unbalanced. By the aid of the technology, the three-phase unbalanced load capacity of the VCS series voltage stable control system is far superior to that of similar products. The excellent three-phase unbalance capability can make the user distribution more flexible, and effectively prevent the occurrence of faults such as asymmetry of output voltage, overlarge zero line current and the like.
In this embodiment, the rectifying and inverting unit 12 is a fully-controlled IGBT power device.
Specifically, the rectifying and inverting unit 12 and the charging device 13 mainly charge the energy storage device 11, and are divided into two stages of constant-current charging and constant-voltage charging. When the whole bus detects voltage abnormity or fault, the cut-off device is disconnected, and the rectification inversion unit 12 mainly has the function of inverting the direct current of the energy storage device 11 into an alternating current power supply to supply power to the rear-end load 2. The rectification inverter unit 12 mainly adopts an IGBT device as a power device, and is mainly characterized by a full-control device. The rectification inversion unit 12 adopts a bidirectional conversion technology, the normal commercial power works as a drive plate and a control part, and the function is mainly charging performance, and the universal drive plate is not changed but is changed into an inversion function when the stored energy is discharged, namely the control function is changed.
In this embodiment, the real-time sampling of the voltage of the power grid 1 by the switching control system and the judgment of whether the voltage of the power grid 1 fluctuates include:
sampling the instantaneous voltage value of the power grid 1 in real time and comparing the instantaneous voltage value with a set threshold value to judge whether the voltage of the power grid 1 fluctuates or not; wherein, the sampling frequency is 6.4KHz, and the voltage drop detection time is 1.5 ms;
meanwhile, a dq coordinate detection method is adopted to convert the three-line alternating voltage sampled in real time into a direct current effective voltage value with equal amplitude, and the direct current effective voltage value is compared with a set threshold value to judge whether the voltage of the power grid 1 fluctuates or not; wherein the maximum detection time is 1.25 ms;
and when the instantaneous voltage values sampled in a plurality of continuous sampling periods are larger than or smaller than the set threshold value and the effective voltage values are continuously detected for a plurality of times to be larger than or smaller than the set threshold value, judging that the voltage fluctuation effective event occurs in the power grid 1, and starting the subsequent switching work.
Specifically, the switching control system is a core principle and a software algorithm for judging the power supply fluctuation of the system. When the power appears undulant, can realize 2-5ms internal transfer 11 contravariant power supply modes of energy memory, its characterized in that: the switching time is guaranteed within 2ms, the voltage sampling and judgment are carried out, the instantaneous value and the effective value are simultaneously calculated, and the voltage of the power grid 1 is sampled in real time to be compared with the set threshold value. And when the voltage value sampled in 10 continuous sampling periods is smaller than the threshold value, the voltage is considered to drop. The sampling frequency fs of the system is 6.4KHz, i.e. the sampling period Ts is 1/6400 us and 156 us. The voltage drop detection time t is 10 × Ts 1.5 ms.
The effective value of (2) is sampled in real time by adopting a dq coordinate detection method to project three-line voltages Ua, Ub and Uc from a three-phase coordinate system to a rotating dq coordinate system. The original 50Hz sine wave becomes assigned equal dc quantities Ud, Uq. The value can be assigned as the voltage drop and rise state can be detected by comparing the amplitude value U with a set threshold value. In order to enhance the detection accuracy of the system, 8 continuous drops or rises are detected and the events are considered to be effective. The maximum examination time is 1.25 ms. When the two principle algorithms judge fluctuation, the voltage fluctuation is determined, and subsequent switching work is started.
In this embodiment, the system further comprises a monitoring platform, the monitoring platform comprises a dynamic reactive power compensation function module, an active filtering function module, a communication interface and a human-computer interaction interface, and meanwhile, the monitoring platform can be expanded to have other functions.
Specifically, the dual-power voltage stabilization control system has the functions of dynamic reactive power compensation and active filtering through the algorithm of control software, and can replace a special reactive power compensation device and an active filtering device. The system comprises a communication system, an interface protection RS232/RS485, an Ethernet port, a dry contact and the like, and can carry out remote data communication and alarm with a DCS control system. The system also comprises a human-computer interface which can check the running state and the fault record in real time.
In this embodiment, this system's equipment parallelly connected work on the generating line, generally parallelly connected use with the low-voltage cabinet, require cabinet type and low-voltage cabinet height the same, because the low-voltage cabinet type difference causes dual supply voltage stable control system's business turn over line different designs also need be different, just need with dual supply voltage stable control system's cabinet body design top parallel A/B/C/N parallel inlet wire mode like the low-voltage cabinet of going up out, and because bus voltage electric current is great, need design the copper bar. For a low-voltage cabinet with side entry and side exit, the cabinet body of a dual-power stable control system needs to be redesigned, and the internal copper bar needs to be readjusted.
The specific application example is as follows:
the hardware part of the system is as follows:
(1) a main cabinet part: a maintenance bypass 6 device, an alternating current input switch, an alternating current output switch, a static switching module, an isolation transformer and a power module (an energy storage device 11);
(2) energy storage cabinet part: a charger (or an inverter, a converter), a super capacitor (or a lithium battery, etc.).
The system software part:
(1) the switching control system is used for sampling voltage, when the power supply fluctuates, the inversion power supply mode of the energy storage device 11 can be switched in within 2-5ms, the switching time is guaranteed within 2ms, the voltage sampling and judgment are carried out, and the instantaneous value and the effective value are adopted for simultaneous calculation.
(2) The monitoring platform system has the functions of dynamic reactive power compensation and active filtering through the algorithm of control software, and can replace a special reactive power compensation device and an active filtering device. Can be in remote data communication and alarm with the DCS control system. The system also comprises a human-computer interface which can check the running state and the fault record in real time.
The working modes comprise:
(1) when the power grid 1 is normal, the equipment is in a power grid voltage power supply mode;
(2) when abnormal conditions such as sag and the like occur in the power grid 1, the equipment is in a power module power supply mode.
The built-in voltage stabilization control system of the voltage stabilization control system is internally provided with a unique delta/Z type isolation transformer, so that complete electrical isolation of inversion output is realized, and the capability of outputting three-phase imbalance is improved: the output voltage precision satisfies: less than or equal to plus or minus 1 percent (balanced load) and less than or equal to plus or minus 2 percent (unbalanced load: 0-0-100 percent and 0-100 percent); the three-phase shift asymmetry satisfies 120 ° ± 1%.
The voltage stabilization control system is provided with a super capacitor as an energy storage device 11, and the charging and discharging times can reach 100 ten thousand;
the super capacitor is planned in series and mainly comprises a control cabinet and a capacitor cabinet, and the capacitor cabinet can be assembled according to the discharge time.
The voltage stabilization control system isolates the control part, the power device and the magnetic device from the air duct completely, and the internal electric part is subjected to three-proofing treatment, so that the dustproof capacity of the plate is effectively improved, and the environmental adaptability of the equipment is enhanced.
The power part of the voltage stabilization control system adopts a modular design, and the design of an internal laminated busbar effectively reduces stray inductance and peak voltage; the closed independent air duct structure improves the heat dissipation effect and ensures smaller temperature rise of the IGBT; and the whole machine can be maintained at the front side, so that the maintenance time is greatly shortened.
The human-computer interaction interface of the voltage stabilization control system comprises: the standard matching liquid crystal touch screen and the matching remote upper computer interface can visually present the real-time working state and the running information of the dynamic voltage regulator and the super capacitor to operation and maintenance personnel, and the operation and maintenance management work is more convenient.
The dual-power-supply voltage stabilization control system provided by the embodiment of the invention can realize that:
1. the response speed is high, the typical response time is 2ms, and the worst case response time is 5ms
The dual-power voltage stabilization control system monitors the voltage condition of the power grid 1 in real time and responds to abnormal conditions of voltage sag, interruption and the like of the power grid 1 in time, and the monitoring response time is less than 100 us; and the power module (energy storage system) continuously works in a grid-connected standby mode, when the voltage of the power grid 1 is abnormal, the power supply mode of the power grid voltage and the power supply mode of the energy storage power module can be quickly switched, so that the normal work of the electric equipment is not influenced by the abnormal conditions of the power grid 1 such as sag and the like.
2. The full power design of the inverter supports the three-phase falling of 100 percent
The full-series machine type power modules of the VCS series voltage stabilization control system are designed to be full power, so that when the voltage of a power grid is abnormal, the power supply mode of the energy storage power module can normally operate, and the power requirement of subsequent energy storage module capacity expansion is met; and the compensation requirement when the voltage of the power grid drops by 100% is supported, the compensation requirement is completely superior to the DL/T-1229 rated compensation requirement (the 7.8.2 rated compensation is preferably more than or equal to 50%), and the method is applicable to the worst condition of the power grid 1.
3. The voltage adjustment target value can be set on site and is default to-15% to + 15% when leaving factory
The voltage stabilization control system fully considers the situation that different power grid voltage fluctuations may exist on site, opens the voltage adjustment target value, and supports site setting so as to adapt to actual site requirements of different customers.
4. The efficiency of the electronic bypass under the working state reaches more than 99 percent, and the electric energy loss cost is greatly reduced
The electronic bypass of the voltage stabilization control system is controlled by adopting a silicon controlled thyristor, and under the working state of the electronic bypass, the whole machine loss is the switching-on loss of the thyristor and the standby loss of the inverter, so that the efficiency can reach more than 99 percent, and the electric energy loss can be greatly reduced;
the overload redundancy capability of the voltage stabilization control system is set by referring to the UPS, and the overload time is completely superior to the standard requirements of DL/T1229-2013:
DL/T1229-2013 standard table
In the voltage stabilization control system, a hierarchical output current-limiting protection technology is adopted for an inverter, so that the output current of a power module cannot be infinitely increased when abnormal conditions such as impact load or short circuit occur, and the series of machine types have extremely strong capacities of resisting step load impact and short circuit;
in the voltage stabilization control system, aiming at the possible abnormal conditions of impact load or short circuit and the like of an electronic bypass, a fast-fusing fuse is installed on the input side of a bypass thyristor, and over 3 times of overcurrent protection is set by software, so that a power device is protected as far as possible while the overload capacity is ensured.
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.
Claims (10)
1. A dual supply voltage stabilization control system, comprising:
the system comprises a bus for connecting a power grid and a load, an energy storage system and a maintenance bypass which are arranged in parallel with the bus, and a switching control system;
one end of the bus is connected with the power grid through a first isolating device, and the other end of the bus is connected with the load;
a first cut-off device, a static switch device and a second cut-off device are sequentially arranged on the bus along the direction from the power grid to the load, and a third cut-off device is arranged on the maintenance bypass;
the energy storage system comprises at least one energy storage device, a rectification inversion unit, a second isolation device and a charging device, wherein the energy storage device, the rectification inversion unit and the isolation device are sequentially connected in series and then are connected with a bus between the static switch device and the second switching-on/off device;
one end of the charging device is connected with a bus between the first cut-off device and the static switch device, and the other end of the charging device is connected with the energy storage device;
the switching control system is used for:
sampling the voltage of the power grid in real time, and judging whether the voltage of the power grid fluctuates or not;
when the voltage of the power grid is judged to be stable, the first switching-off device, the static switch device and the second switching-off device are controlled to be switched on, and the third switching-off device is controlled to be switched off, so that the power grid supplies power to the load through the bus, and meanwhile, the charging device and the rectification inversion unit charge the energy storage device;
and when the voltage of the power grid is judged to fluctuate, the static switch device is controlled to be switched off, and the rectification inversion unit is controlled to convert the direct current output by the energy storage device into alternating current to supply power to the load.
2. The dual supply voltage stabilization control system of claim 1, wherein the switching control system is further configured to:
when the system needs maintenance and detection, the first cut-off device, the static switch device and the second cut-off device are controlled to be turned off, and the third cut-off device is controlled to be turned on, so that the power grid supplies power to the load through the maintenance bypass.
3. The dual supply voltage stabilization control system of claim 1 or 2, wherein the first and second cut-off devices are circuit breakers or contactors;
the static switch device is a silicon controlled static switch;
the third switching device is a contactor or a load switch.
4. The dual-power-supply voltage stabilization control system of claim 3, wherein a standby bypass connected with the silicon controlled static switch in parallel is arranged on the bus at the silicon controlled static switch, and a circuit breaker or a contactor is arranged on the standby bypass.
5. The dual supply voltage stabilization control system of claim 1, wherein the energy storage device comprises at least one of a supercapacitor and a lithium ion battery.
6. The dual-power-supply voltage stabilization control system of claim 5, wherein the energy storage device is a super capacitor, and the super capacitor is arranged in a capacitor cabinet;
the capacitor box adopts a modular design, and a plurality of capacitor boxes can be spliced according to the discharge time.
7. The dual-supply voltage stabilization control system of claim 1, wherein the other end of the bus is connected to the load through a third isolation device;
the first isolating device, the second isolating device and the third isolating device are pure copper or enameled aluminum transformers;
the transformer is a delta/Z type isolation transformer, and the insulation grade of the transformer is H.
8. The dual-power-supply voltage stabilization control system of claim 1, wherein the rectification inversion unit is a fully-controlled IGBT power device.
9. The dual-power-supply voltage stabilization control system of claim 1, wherein the switching control system samples the voltage of the power grid in real time and judges whether the voltage of the power grid fluctuates comprises:
sampling the instantaneous voltage value of the power grid in real time and comparing the instantaneous voltage value with a set threshold value to judge whether the voltage of the power grid fluctuates or not; wherein, the sampling frequency is 6.4KHz, and the voltage drop detection time is 1.5 ms;
meanwhile, a dq coordinate detection method is adopted to convert the three-line alternating voltage sampled in real time into a direct current effective voltage value with equal amplitude, and the direct current effective voltage value is compared with a set threshold value to judge whether the voltage of the power grid fluctuates; wherein the maximum detection time is 1.25 ms;
and when the instantaneous voltage values sampled in a plurality of continuous sampling periods are larger than or smaller than the set threshold value and the effective voltage values are continuously detected for a plurality of times to be larger than or smaller than the set threshold value, judging that the voltage fluctuation effective event occurs in the power grid, and starting the subsequent switching work.
10. The dual-power-supply voltage stabilization control system of claim 1, further comprising a monitoring platform, wherein the monitoring platform comprises a dynamic reactive compensation function module, an active filtering function module, a communication interface and a human-computer interaction interface.
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| CN114977504A (en) * | 2022-06-02 | 2022-08-30 | 国网山东省电力公司泰安供电公司 | Bypass load switch control system |
| CN115622211A (en) * | 2022-10-12 | 2023-01-17 | 南京智睿能源互联网研究院有限公司 | A Modular Dynamic Voltage Restoration Device Circuit |
| CN119070317A (en) * | 2024-11-07 | 2024-12-03 | 山东华天电气有限公司 | A linkage control system and control method of a modular dynamic voltage restorer |
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