CN108899935B - And off-network switching equipment and system - Google Patents
And off-network switching equipment and system Download PDFInfo
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- CN108899935B CN108899935B CN201810935770.3A CN201810935770A CN108899935B CN 108899935 B CN108899935 B CN 108899935B CN 201810935770 A CN201810935770 A CN 201810935770A CN 108899935 B CN108899935 B CN 108899935B
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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
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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
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
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- Supply And Distribution Of Alternating Current (AREA)
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Abstract
The present invention relates to a kind of and off-network switching equipment and systems, it should off-network switching equipment include simultaneously grid entry point switch, bi-directional current inverter, isolated island detecting device and energy storage device, wherein: grid entry point switch includes control terminal and two connection terminals, and two connection terminals are for being separately connected microgrid and public electric wire net；Bi-directional current inverter one end connects microgrid, and the other end connects energy storage device；Isolated island detecting device is separately connected the control terminal of public electric wire net, microgrid and grid entry point switch.Above-mentioned and off-network switching equipment and system, when isolated island detecting device detects that microgrid is in island state, in simultaneously off-network handoff procedure, bi-directional current inverter can control energy storage device and provide short circuit current and energy support for public electric wire net fault point, and clamp down on microgrid voltage, to accelerate the speed of microgrid and off-network switching, and improve the success rate of microgrid and off-network switching.
Description
Technical field
The present invention relates to microgrid fields, more particularly to a kind of and off-network switching equipment and system.
Background technique
Microgrid refers to be made of distributed generation resource, energy storage device, energy conversion device, load, monitoring and protective device etc.
Small-sized electric system.Microgrid has grid-connected and off-network two states, and the switching between both states, as and off-network is cut
It changes.
It is carried out under unplanned island state and a kind of situation of off-network switching is, it is micro- when public electric wire net breaks down
Net is switched to off-grid operation from grid-connected, into island state.Under this situation and off-network switches, and need to generally detect and send out in microgrid
After existing island state and regulation power balance, disconnection grid entry point switchs to complete and off-network switches, therefore switching time is longer.
In addition, due to public electric wire net failure, microgrid needs send power to provide short circuit current to bulk power grid or for short dot, therefore
And during off-network switches, microgrid internal power is easy unbalance, causes microgrid voltage, frequency unstable, even sends out when serious
Raw microgrid collapses the situation of net, so that simultaneously off-network handover failure.Therefore, needing to develop a kind of can improve microgrid simultaneously under island state
The technology of off-network switch speed and success rate.
Summary of the invention
Based on this, it is necessary to a kind of and off-network switching equipment and system are provided, it can the raising when microgrid enters island state
Microgrid and the speed and success rate of off-network switching.
A kind of and off-network switching equipment, including grid entry point switch, bi-directional current inverter, isolated island detecting device and energy storage dress
It sets, in which: grid entry point switch includes control terminal and two connection terminals, and two connection terminals are for being separately connected microgrid and common electrical
Net；Bi-directional current inverter one end connects microgrid, and the other end connects energy storage device；Isolated island detecting device is separately connected common electrical
The control terminal of net, microgrid and grid entry point switch.
Above-mentioned and off-network switching equipment is cut when isolated island detecting device detects that microgrid is in island state in simultaneously off-network
During changing, bi-directional current inverter can control energy storage device and provide short circuit current and energy branch for public electric wire net fault point
Support, and microgrid voltage is clamped down on, to accelerate the speed of microgrid and off-network switching, and improve the success rate of microgrid and off-network switching.
Bi-directional current inverter is used to fill energy storage when microgrid carries out and off-network switches in one of the embodiments,
The electric energy for setting storage is changed into alternating current；
Bi-directional current inverter is also used to when microgrid is in grid connection state, by AC rectification be direct current be energy storage dress
Set charging.
Bi-directional current inverter is the bi-directional current inverter with droop characteristic in one of the embodiments,.
Bi-directional current inverter is also used to when microgrid is in grid connection state, according to sagging in one of the embodiments,
The target state-of-charge of energy storage device is set preset upper limit value by characteristic, and is preset minimum by interaction power setting
Value.
Bi-directional current inverter is also used to when microgrid is in island state, according to sagging in one of the embodiments,
Characteristics Control energy storage device output power and short circuit current.
Isolated island detecting device includes: acquisition unit in one of the embodiments, for acquiring the frequency of public electric wire net；
Judging unit judges whether microgrid is in island state for the frequency according to public electric wire net；Switch unit, for single in judgement
The judging result of member is cutting grid entry point switch when being.
Isolated island detecting device further includes control unit in one of the embodiments, for controlling bi-directional current inverter
Sagging control frequency base value.
Grid entry point switch is remote control switch in one of the embodiments,.
Bi-directional current inverter one end is connect by power line with microgrid bus in one of the embodiments, the other end
It is connect by power line with energy storage device；Isolated island detecting device is connect by gathering line with public electric wire net bus and microgrid bus,
Isolated island detecting device is connect by control line with the control terminal that grid entry point switchs.
A kind of and off-network switching system, including microgrid, public electric wire net and such as any of the above-described and off-network switching equipment,
Middle microgrid and public electric wire net are connect with simultaneously off-network switching equipment respectively.
Above-mentioned and off-network switching system is cut when isolated island detecting device detects that microgrid is in island state in simultaneously off-network
During changing, bi-directional current inverter can control energy storage device and provide short circuit current and energy branch for public electric wire net fault point
Support, and microgrid voltage is clamped down on, to accelerate the speed of microgrid and off-network switching, and improve the success rate of microgrid and off-network switching.
Detailed description of the invention
Fig. 1 is one embodiment of the invention and off-network switching equipment structural schematic diagram；
Fig. 2 be one embodiment of the invention and in off-network switching equipment isolated island detecting device structural schematic diagram.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that specific embodiment described herein is only used to explain the present invention, not
For limiting the present invention.
In one embodiment, a kind of and off-network switching equipment, including grid entry point switch, bi-directional current inverter, isolated island
Detection device and energy storage device, in which: grid entry point switch includes control terminal and two connection terminals, and two connection terminals are for distinguishing
Connect microgrid and public electric wire net；Bi-directional current inverter one end connects microgrid, and the other end connects energy storage device；Isolated island detecting device
It is separately connected the control terminal of public electric wire net, microgrid and grid entry point switch.Inverter uses specification in one of the embodiments,
For the two-way inverter of energy storage of PCS21A-500kW.Isolated island monitoring device is using in MG2510-BW in one of the embodiments,
Entreat controller.
A kind of and off-network switching system in one of the embodiments, comprising microgrid, public electric wire net and any embodiment
Described and off-network switching equipment, wherein microgrid and public electric wire net are separately connected above-mentioned and off-network switching equipment.
In above-described embodiment, when isolated island detecting device detects that microgrid is in island state, in simultaneously off-network handoff procedure
In, bi-directional current inverter can control energy storage device and provide short circuit current and energy support for public electric wire net fault point, and clamp
Microgrid voltage processed to accelerate the speed of microgrid and off-network switching, and improves the success rate of microgrid and off-network switching.
In one of the embodiments, as shown in Figure 1, providing a kind of and off-network switching equipment 10, including grid entry point is opened
Close 110, bi-directional current inverter 120, isolated island detecting device 130 and energy storage device 140, in which: grid entry point switch 110 includes control
Terminal 110a processed and two connection terminal 110b, 110c, a connection terminal 110b is for connecting public electric wire net, another connection terminal
110c is for connecting microgrid；120 one end of bi-directional current inverter connects microgrid, and the other end connects energy storage device 140；Isolated island detection
Device 130 is separately connected the control terminal 110a of public electric wire net, microgrid and grid entry point switch 110.
Wherein, the solid line of Fig. 1 indicates to be electrically connected, this electric connection can be realized by power line, gathering line and control line.
Such as 120 one end of bi-directional current inverter is connect by power line with microgrid bus, the other end passes through power line and energy storage device
Connection；Isolated island detecting device 130 is connect by gathering line with public electric wire net bus and microgrid bus, and isolated island detecting device 130 is logical
It crosses control line and is connect with the control terminal 110a that grid entry point switchs.
Public electric wire net is switched by grid entry point and is connected with microgrid in one of the embodiments, bi-directional current inverter
One end is electrically connected with sagging mode by power line and microgrid bus, the other end of bi-directional current inverter by power line with
Energy storage device is electrically connected.
Wherein, the dotted line of Fig. 1 indicates communication connection, i.e. grid entry point switch 110, the detection of 120 isolated island of bi-directional current inverter
Device 130 and between communicate with each other connection.
In the present embodiment, isolated island detecting device is for detecting whether microgrid enters island state, if detecting, microgrid enters
Island state, the then control terminal switched to grid entry point send control signal, disconnect grid entry point switch, meanwhile, bi-directional current
Inverter control energy storage device output power provides short circuit current for fault point, to support microgrid voltage and frequency, improves isolated island
The speed and success rate of under state and off-network switching.
Isolated island detecting device uses passive detection method in one of the embodiments, utilizes inverter when grid cut-off
The variation of the voltage of output end, frequency, phase or harmonic wave carries out island effect detection.For example, using/under-voltage and mistake/under-frequency
Detection method stops grid-connected inverters operation, if voltage when the voltage magnitude and frequency of point of common coupling are more than preset range
Or frequency shift (FS) reaches isolated island detection setting threshold values (also known as threshold value), then isolated island can be detected.One embodiment wherein
In, isolated island detecting device carries out isolated island using the variation of the voltage of inverter output end when grid cut-off, frequency, phase or harmonic wave
Effect detection.For example, isolated island detecting device includes acquisition unit, judging unit and switch unit, acquisition unit is for acquiring public affairs
The voltage magnitude and frequency of Coupling point altogether；Judging unit is set for judging whether the offset of above-mentioned voltage magnitude or frequency reaches
Determine threshold value, be, determines that microgrid is in island state, switch unit is used to cut off institute when the judging result of judging unit is to be
State grid entry point switch.For another example, isolated island detecting device includes detection unit, judging unit and switch unit, and detection unit is for examining
The total harmonic distortion of the output voltage of gird-connected inverter is surveyed, judging unit is for judging whether above-mentioned total harmonic distortion is more than setting
Threshold value is to determine that microgrid is in island state, and switch unit is used for when the judging result of judging unit is to be, described in cutting
Grid entry point switch.
Isolated island detecting device uses voltage harmonic detection method in one of the embodiments, by detecting gird-connected inverter
The total harmonic distortion of output voltage whether out-of-limit detect whether island phenomenon occurs.Isolated island in one of the embodiments,
Detection device detects whether island phenomenon is sent out by the way that whether the total harmonic distortion for detecting the output voltage of gird-connected inverter is out-of-limit
It is raw.When micro-grid connection works, output current harmonics will flow into power grid by point of common coupling.Due to power grid network impedance very
It is small, therefore the total harmonic distortion factor of the point of common coupling voltage is usually lower.When microgrid and public electric wire net disconnect, due to load
Impedance is usually more much bigger than electric network impedance, therefore the point of common coupling voltage will generate very big harmonic wave, by detecting voltage
The variation of harmonic wave or harmonic wave can effectively detect the generation of island effect；For example, point of common coupling voltage is using harmonic wave electricity
It flows and is obtained with the product of load impedance.For example, output voltage and electricity that isolated island detecting device passes through detection micro-grid connection inverter
The phase difference of stream changes to detect the generation of island phenomenon.Micro-grid connection is usually operated at unity power factor mode when running,
I.e. microgrid output Current Voltage is the same as the same phase of frequency.After microgrid and public electric wire net disconnect, there is the independent powering load of microgrid
Island phenomenon, at this point, the phase of point of common coupling voltage will mutate, so as to using Phase jump detection method come
Judge whether island phenomenon occurs.
Isolated island detecting device includes disturbing unit to make its output work for controlling inverter in one of the embodiments,
There are certain disturbances for rate, frequency or phase；Acquisition unit, for acquiring the output disturbance of inverter；Judging unit, for sentencing
Whether the output disturbance of disconnected inverter reaches preset range, is to determine that microgrid enters island state.Wherein, public electric wire net is normal
When work, due to the balanced action of public electric wire net, it can't detect these disturbances.Once public electric wire net breaks down, inverter is defeated
Disturbance out is by accelerated accumulation and exceeds allowed band, to trigger island effect detection circuit.For example, disturbance unit is for controlling
The electric current that gird-connected inverter output frequency processed is slightly distorted, to form the continuous trend for changing frequency；Acquisition unit is used for
Acquisition judges the output voltage and electric current of inverter；Judging unit be used for judge inverter output voltage and electric current whether be more than
The boundary value of frequency protection is to determine that microgrid enters island state.For example, disturbance unit is used to control the output electricity of inverter
Stream, making it, there are certain phase differences between common point voltage；Acquisition unit is used to acquire the frequency of common point after power grid decompression；
Judging unit is used to judge whether the frequency of common point after power grid decompression deviates preset normal range (NR), is to determine that microgrid enters
Island state.Under normal circumstances, when inverter and when power distribution network parallel running, power distribution network by provide fixed Reference Phase Angle and
Frequency makes inverter stabilization of operating point in power frequency.After isolated island is formed, if inverter output voltage frequency has minor fluctuations,
Inverter phase response curve can be such that phase error increases, and reach a new steady s tate point.The frequency of new state point will surpass
/ under-frequency operating valve value is crossed out, to detect island phenomenon.For example, disturbance is single for the inverter of current source control type
Member is for reducing microgrid inverter and exporting electric current, change its active power of output every some cycles.When grid-connected inverters are run
When, constant output voltage is network voltage；When grid cut-off, inverter output voltage is determined by load.Every electric current is disturbed
Dynamic moment, output current amplitude change, then load upper voltage and change therewith.Acquisition unit is for acquiring load voltage；Judgement is single
Member is to determine that microgrid enters island state for judging whether load voltage reaches under-voltage range.For example, disturbance unit is used
Dead zone is added in the output current wave in some period of inverter.The change of inverter current waveform will cause output voltage
The mutation of frequency, acquisition unit then are used to acquire the variation of output voltage frequency, that is, acquire the vibration mode of output voltage frequency；
Judging unit judges whether the vibration mode of inverter output voltage frequency meets preset vibration mode, be determine it is micro-
Net enters island state.Based on said structure design, isolated island detecting device uses active detecting side in one of the embodiments,
Whether method, detection microgrid enter island state.By controlling inverter, there is its output power, frequency or phase centainly
Disturbance.When public electric wire net works normally, due to the balanced action of public electric wire net, it can't detect these disturbances.Once public electric wire net
It breaks down, the disturbance of inverter output by accelerated accumulation and exceeds allowed band, to trigger island effect detection circuit.?
In one embodiment, isolated island detecting device uses frequency offset detection method, is distorted gird-connected inverter output frequency slightly
Electric current eventually lead to the boundary of output voltage and the protection of electric current overfrequency to form the continuous trend for changing frequency
Value, to achieve the purpose that anti-islanding effect.Isolated island detecting device is detected using sliding formwork frequency drift in one of the embodiments,
Method controls the output electric current of inverter, and making it, there are certain phase differences between common point voltage, to public after power grid decompression
The frequency departure normal range (NR) of concurrent and differentiate isolated island.Isolated island detecting device uses periodic current in one of the embodiments,
Interference Detection method, every some cycles, reduces microgrid inverter and exports electric current for the inverter of current source control type,
Then change its active power of output.Isolated island detecting device uses frequency discontinuity detection method in one of the embodiments, in inversion
Dead zone is added in the output current wave in some period of device, the change of inverter current waveform will cause frequency discontinuity.
Grid entry point switch 110 is remote control switch in one of the embodiments,.Such as grid entry point switch 110 is distant to have
The high-speed switch of control folding function.In this way, can realize microgrid and off-network seamless switching by high-speed switch, support microgrid with public
The quick separating of power grid, prevents failure propagation.
Bi-directional current inverter is used to fill energy storage when microgrid carries out and off-network switches in one of the embodiments,
The electric energy for setting storage is changed into alternating current；Bi-directional current inverter is also used to when microgrid is in grid connection state, and alternating current is whole
Stream is that direct current is energy storage device charging.
Energy storage device is the energy-storage battery for having fast charging and discharging ability in one of the embodiments,.In this way, once going out
Existing island phenomenon, energy storage device quickly can provide short circuit current for fault point, provide support for microgrid voltage and frequency, further
Improve the speed and success rate of the switching of under island state and off-network.
Bi-directional current inverter is the bi-directional current inverter with droop characteristic in one of the embodiments,.It is two-way
Trend inverter detects itself output power, obtains the instruction value of output voltage frequency and amplitude by droop characteristic, then instead
Finely tune its output voltage amplitude and frequency mutually to reach the active reasonable distribution with reactive power of system.
Bi-directional current inverter is also used to when microgrid is in grid connection state, according to sagging in one of the embodiments,
The target state-of-charge of energy storage device is set preset upper limit value by characteristic, and is preset minimum by interaction power setting
Value.In this way, can control in micro-grid connection operation, so that the additional energy for being somebody's turn to do simultaneously off-network switching equipment minimizes.For example, will hand over
Cross-power is set as 0, can control in micro-grid connection operation, should and off-network switching equipment additional energy close to 0.
Bi-directional current inverter is also used to when microgrid is in island state, according to sagging in one of the embodiments,
Characteristics Control energy storage device output power and short circuit current.When breaking down outside microgrid, generating island phenomenon, it is passive and from
Net switching operating condition generates, and the droop characteristic control energy storage device output power of bi-directional current inverter provides short circuit current, thus
Support microgrid voltage and frequency.
Isolated island detecting device includes: acquisition unit in one of the embodiments, for acquiring the frequency of public electric wire net；
Judging unit judges whether microgrid is in island state for the frequency according to public electric wire net；Switch unit, for single in judgement
The judging result of member is cutting grid entry point switch when being.In one of the embodiments, as shown in Fig. 2, isolated island detecting device
130 include acquisition unit 131, judging unit 132, switch unit 133 and control unit 134, in which: acquisition unit 131 is used for
Acquire the frequency of public electric wire net；Judging unit 132 is used to judge whether microgrid is in island state according to the frequency of public electric wire net；
Switch unit 133 is used for when the judging result of judging unit is to be, cutting grid entry point switch；Control unit 134 is for controlling
The sagging control frequency base value of bi-directional current inverter.
Control unit is also used to raise two-way when the judging result of judging unit, which is, is in one of the embodiments,
The sagging control frequency base value of trend inverter.When isolated island detecting device detects that microgrid enters island state, control grid-connected
Point switch disconnects and raises the sagging control frequency base value of bi-directional current inverter, to improve the support power of output, and adds
The support of strong microgrid voltage and frequency.Shorten and the time of off-network switching, improve unplanned isolated island and off-network handover success rate.
Provide a kind of and off-network switching system in one of the embodiments, including microgrid, public electric wire net and as above-mentioned
Any embodiment and off-network switching equipment, wherein microgrid and public electric wire net respectively with and off-network switching equipment connect.For example, simultaneously
Off-network switching equipment includes grid entry point switch, bi-directional current inverter, isolated island detecting device and energy storage device.Grid entry point switch packet
Control terminal and two connection terminals are included, a connection terminal of grid entry point switch connects microgrid, another connecting pin of grid entry point switch
Son connection public electric wire net, the control terminal of grid entry point switch are connect with isolated island detecting device；Isolated island detecting device is separately connected micro-
Net and public electric wire net.Bi-directional current inverter one end connects microgrid, and the other end connects energy storage device.
Above-mentioned and off-network switching system is cut when isolated island detecting device detects that microgrid is in island state in simultaneously off-network
During changing, bi-directional current inverter can control energy storage device and provide short circuit current and energy branch for public electric wire net fault point
Support, and microgrid voltage is clamped down on, to accelerate the speed of microgrid and off-network switching, and improve the success rate of microgrid and off-network switching.
Each technical characteristic of above embodiments can be combined arbitrarily, for simplicity of description, not to above-described embodiment
In each technical characteristic it is all possible combination be all described, as long as however, the combination of these technical characteristics be not present lance
Shield all should be considered as described in this specification.
Only several embodiments of the present invention are expressed for above embodiments, and the description thereof is more specific and detailed, but can not
Therefore it is construed as limiting the scope of the patent.It should be pointed out that for those of ordinary skill in the art,
Under the premise of not departing from present inventive concept, various modifications and improvements can be made, and these are all within the scope of protection of the present invention.
Therefore, the scope of protection of the patent of the invention shall be subject to the appended claims.
Claims (10)
1. a kind of and off-network switching equipment, which is characterized in that including grid entry point switch, bi-directional current inverter, isolated island detection dress
It sets and energy storage device, in which:
The grid entry point switch includes control terminal and two connection terminals, and two connection terminal is for being separately connected microgrid and public affairs
Common-battery net；
Bi-directional current inverter one end connects the microgrid, and the other end connects the energy storage device；
The isolated island detecting device is separately connected the control terminal of the public electric wire net, the microgrid and grid entry point switch；
The isolated island detecting device includes detection unit, judging unit and switch unit, and the detection unit is described for detecting
The total harmonic distortion of the output voltage of bi-directional current inverter, the judging unit is for judging whether the total harmonic distortion surpasses
Given threshold is crossed, is, determines that microgrid is in island state, the switch unit is used for the judging result in the judging unit
When to be, the grid entry point switch is cut off；
The isolated island detecting device further includes control unit, and the judging result that described control unit is used to work as the judging unit is
When being, the sagging control frequency base value of the bi-directional current inverter is controlled；
The bi-directional current inverter is the bi-directional current inverter with droop characteristic, and the bi-directional current inverter is also used to
When the microgrid is in grid connection state, set pre- for the target state-of-charge of the energy storage device according to the droop characteristic
If upper limit value, and will interaction power setting be preset minimum value.
2. according to claim 1 and off-network switching equipment, it is characterised in that:
The bi-directional current inverter is used for the electric energy for storing the energy storage device when the microgrid carries out and off-network switches
It is changed into alternating current；
The bi-directional current inverter is also used to when the microgrid is in grid connection state, be direct current by AC rectification is institute
State energy storage device charging.
3. according to claim 2 and off-network switching equipment, which is characterized in that the grid entry point switch, the two-way tide
Connection is communicated with each other between stream inverter and the isolated island detecting device.
4. according to claim 1 and off-network switching equipment, which is characterized in that the energy storage device is to have quick charge and discharge
The energy-storage battery of electric energy power.
5. according to claim 1 and off-network switching equipment, which is characterized in that the bi-directional current inverter is also used to work as
When the microgrid is in island state, the energy storage device output power and short circuit current are controlled according to the droop characteristic.
6. according to claim 3 and off-network switching equipment, which is characterized in that one end of the bi-directional current inverter with
Sagging mode is electrically connected by the bus of power line and the microgrid, and the other end of the bi-directional current inverter passes through electric power
Line and the energy storage device are electrically connected.
7. according to claim 1 and off-network switching equipment, which is characterized in that the grid entry point switch is remote control switch.
8. according to claim 1 and off-network switching equipment, which is characterized in that the grid entry point switch is opened to have remote control
Close the high-speed switch of function.
9. according to claim 1 described in any one of -7 and off-network switching equipment, which is characterized in that
Bi-directional current inverter one end is connect by power line with microgrid bus, and the other end passes through power line and the energy storage
Device connection；
The isolated island detecting device is connect by gathering line with public electric wire net bus and the microgrid bus, the isolated island detection dress
It sets and is connect by control line with the control terminal that the grid entry point switchs.
10. a kind of and off-network switching system, which is characterized in that including microgrid, public electric wire net and such as any one of claims 1 to 9
Described and off-network switching equipment, wherein the microgrid and the public electric wire net are connect with described and off-network switching equipment respectively.
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| CN113988478B (en) * | 2021-12-03 | 2024-10-15 | 国网黑龙江省电力有限公司电力科学研究院 | Distributed economic optimization method for direct-current micro-grid interconnection system based on equal micro-increment rate |
| CN114865704B (en) * | 2022-06-08 | 2022-12-16 | 南通大学 | Grid-connected and grid-disconnected switching control method and system of two-stage energy storage converter |
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Effective date of registration: 20200922 Address after: 510620 Tianhe District, Guangzhou, Tianhe South Road, No. two, No. 2, No. Patentee after: Guangzhou Power Supply Bureau of Guangdong Power Grid Co.,Ltd. Address before: 510620 Tianhe District, Guangzhou, Tianhe South Road, No. two, No. 2, No. Patentee before: GUANGZHOU POWER SUPPLY Co.,Ltd. |