CN111244999B - Control method of hybrid energy consumption device - Google Patents
Control method of hybrid energy consumption device Download PDFInfo
- Publication number
- CN111244999B CN111244999B CN202010049754.1A CN202010049754A CN111244999B CN 111244999 B CN111244999 B CN 111244999B CN 202010049754 A CN202010049754 A CN 202010049754A CN 111244999 B CN111244999 B CN 111244999B
- Authority
- CN
- China
- Prior art keywords
- energy consumption
- consumption device
- distributed
- distributed energy
- centralized
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
-
- 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
- H02J3/14—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
- Y02B70/3225—Demand response systems, e.g. load shedding, peak shaving
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
-
- 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
- Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
- Y04S20/20—End-user application control systems
- Y04S20/222—Demand response systems, e.g. load shedding, peak shaving
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
Abstract
The invention relates to a hybrid energy consumption device and a control method thereof, wherein the hybrid energy consumption device comprises a centralized energy consumption device and a distributed energy consumption device which are connected in parallel at a direct current line end; the centralized energy consumption device and the distributed energy consumption device can be put into operation independently or simultaneously. The invention inherits the stable direct current voltage of the distributed energy consumption device during the fault period, reduces the current-resistant through-current capacity of the semiconductor device of the distributed energy consumption device by introducing the centralized energy consumption device, and reduces the cost of the energy consumption device.
Description
Technical Field
The invention relates to the technical field of high-power electronic current transformation, in particular to a hybrid energy consumption device and a control method thereof.
Background
The flexible direct current transmission system has self-turn-off capability, does not need additional commutation voltage, overcomes the fundamental defect that the receiving end of the traditional high-voltage direct current system must be an active network, and becomes an excellent solution for island power transmission and offshore wind power transmission. In a flexible direct current transmission system, after an alternating current system fault occurs in a receiving end system, the power of a sending end system cannot be sent out during the fault, so that the voltage of a direct current line is increased, and the insulation level of the equipment of the whole system is seriously tested. The energy consumption device is used as important equipment of the flexible direct current transmission system, and plays a role in consuming energy which cannot be borne by a receiving end system so as to protect the equipment of the whole system.
At present, energy consumption devices are divided into an alternating current energy consumption device and a direct current energy consumption device. The alternating current energy consumption device is mainly used for consuming surplus power by applying a braking resistor on an alternating current side when a direct current transmission line fails. When the scheme is applied to an offshore platform, great economic cost is increased, and the scheme is not suitable for an offshore flexible direct current transmission system.
The direct current energy consumption device is mainly divided into a centralized energy consumption device and a distributed energy consumption device. The centralized energy consumption device consists of energy consumption branches and energy consumption resistors, and the energy consumption resistors are switched after the DC voltage is detected to be increased to bear surplus power consumption, but the centralized energy consumption device cannot keep the stability of the DC voltage in the switching stage; the distributed energy consumption device can still keep the stability of direct current voltage at the input stage of the energy consumption device and has high performance, but the distributed energy consumption device is composed of a large number of sub-modules, each sub-module contains a semiconductor IGBT device, and the cost of the distributed energy consumption device is increased to a certain extent due to the high price of the IGBT.
Disclosure of Invention
In view of the above, an objective of the present invention is to provide a hybrid energy consuming apparatus and a control method thereof, which inherit the fact that a distributed energy consuming apparatus can stabilize a dc voltage during a fault period, and reduce the current-resistant capability of a semiconductor device of the distributed energy consuming apparatus by introducing a centralized energy consuming apparatus, thereby reducing the cost of the energy consuming apparatus.
The invention is realized by adopting the following scheme: a hybrid energy consumption device comprises a centralized energy consumption device and a distributed energy consumption device which are connected in parallel at a direct current line end; the centralized energy consumption device and the distributed energy consumption device can be put into operation independently or simultaneously.
Furthermore, the centralized energy consumption device is composed of energy consumption branch circuits and energy consumption resistors, and each energy consumption branch circuit is formed by connecting at least one energy consumption submodule in series in the same direction.
Furthermore, the distributed energy consumption device is composed of a plurality of voltage-sharing energy consumption modules (energy consumption sub-modules), the voltage-sharing energy consumption modules are connected in series, and each energy consumption sub-module is composed of an energy consumption unit, an energy storage unit and a controllable switch.
Further, the designed rated power of the distributed energy consumption device is larger than 2/3 rated power of the system, and the designed rated power of the centralized energy consumption device is larger than 1/3 rated power of the system.
The invention also provides a control method of the hybrid energy consumption device, when the voltage of the direct current line is higher than a preset value, the hybrid energy consumption device is preferentially selected to be put into the distributed energy consumption device; when the distributed energy consumption device can not completely consume the redundant energy, the centralized energy consumption device is simultaneously put into use.
Further, the method comprises the following steps:
step S1: real-time detection of DC line voltage UdlWhen the receiving end AC system is in fault, the voltage of the DC line rises, and surplus power P consumed by the energy consumption device is calculatedloss；
Step S2: when the DC voltage U is detecteddlWhen the operation threshold value is increased and is larger than the action threshold value of the distributed energy consumption device, the distributed energy consumption device is put into the distributed energy consumption device according to the surplus power;
step S3: judgment of PlossAnd the rated power P of the system0If P is a relationship betweenloss/P0<2/3, only the distributed energy consumption devices need to be put into use; if Ploss/P0>2/3, the distributed energy consuming devices and the centralized energy consuming devices are simultaneously put into operation.
Further, the voltage of the direct current line is monitored in real time, when the voltage of the direct current line is normal, the distributed energy consumption device is precharged, and after the precharging is completed, the distributed energy consumption device is in a hot standby state.
Furthermore, when the most common single-phase fault occurs in the receiving-end alternating-current power grid, only the distributed energy consumption devices are put into use; when a serious alternating-current two-phase fault or three-phase fault occurs in a receiving-end alternating-current power grid, a distributed energy consumption device and a centralized energy consumption device are simultaneously put into use, and the centralized energy consumption device can bear energy which needs to be consumed.
Compared with the prior art, the invention has the following beneficial effects:
1. the device and the method adopt a method of combining the distributed energy consumption device and the centralized energy consumption device, the device inherits that the distributed energy consumption device can stabilize direct-current voltage during the fault period, and the current-resistant through-current capacity of the semiconductor device of the distributed energy consumption device is reduced by introducing the centralized energy consumption device, so that the cost of the energy consumption device is reduced;
2. the control method of the device distinguishes different input modes aiming at different types of alternating current system faults, reduces the current endurance capacity of the distributed energy consumption device by utilizing the rapid energy consumption characteristic of the centralized energy consumption device, and greatly reduces the cost of the energy consumption device.
Drawings
FIG. 1 is a schematic diagram of a system according to an embodiment of the present invention.
Fig. 2 is a common sub-module topology of a distributed energy consumption device according to an embodiment of the present invention.
Fig. 3 is a centralized energy consumption device topology according to an embodiment of the invention. In the figure, 1 is an energy consumption branch, 2 is an energy consumption module, 3 is an energy consumption resistor, 4 is a bypass switch, 5 is a charging bypass resistor, 6 is a charging switch, and 7 is an isolating switch.
Detailed Description
The invention is further explained below with reference to the drawings and the embodiments.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
As shown in fig. 1, the present embodiment provides a hybrid energy consumption device, which includes a centralized energy consumption device and a distributed energy consumption device connected in parallel to a dc line; the centralized energy consumption device and the distributed energy consumption device can be put into operation independently or simultaneously.
In this embodiment, as shown in fig. 3, the centralized energy consumption device is composed of an energy consumption branch 1 and an energy consumption resistor 3, and the energy consumption branch is formed by connecting at least one energy consumption submodule 2 in series in the same direction. An auxiliary isolating switch 7 and a charging bypass resistor 5 are additionally included; the energy consumption branch 1 is composed of a plurality of energy consumption modules 2, and two ends of each energy consumption module are also connected with a bypass switch 4 in parallel.
In this embodiment, as shown in fig. 2, the distributed energy consumption device is composed of a plurality of voltage-sharing energy consumption modules (energy consumption sub-modules), the voltage-sharing energy consumption modules are connected in series, and each energy consumption sub-module is composed of an energy consumption unit (resistor Rb), an energy storage unit (capacitor C) and a controllable switch (semiconductor device IGBT).
In this embodiment, the designed rated power of the distributed energy consumption device is greater than the 2/3 rated power of the system, and the designed rated power of the centralized energy consumption device is greater than the 1/3 rated power of the system.
The embodiment also provides a control method of the hybrid energy consumption device, wherein when the voltage of the direct current line is higher than a preset value, the hybrid energy consumption device is preferentially selected to be put into the distributed energy consumption device; when the distributed energy consumption device can not completely consume the redundant energy, the centralized energy consumption device is simultaneously put into use.
In this embodiment, the method comprises the following steps:
step S1: real-time detection of DC line voltage UdlWhen the receiving end AC system is in fault, the voltage of the DC line rises, and surplus power P consumed by the energy consumption device is calculatedloss；
Step S2: when the DC voltage U is detecteddlWhen the temperature rises and is larger than the action threshold value of the distributed energy consumption device, the distributed energy consumption device is put into the operation according to the magnitude of surplus power;
step S3: judgment of PlossRated power P of system0If P is a relationship betweenloss/P0<2/3, only the distributed energy consumption devices need to be put into use; if Ploss/P0>2/3, the distributed energy consuming devices and the centralized energy consuming devices are simultaneously input.
In this embodiment, the voltage of the dc line is monitored in real time, when the voltage of the dc line is normal, the distributed energy consuming device is precharged, and after the precharge is completed, the distributed energy consuming device is in a hot standby state.
In this embodiment, when the most common single-phase fault occurs in the receiving-end ac grid, only the distributed energy consumption device is put into use; when a receiving end alternating current power grid has a serious alternating current two-phase fault or a serious alternating current three-phase fault, the distributed energy consumption device and the centralized energy consumption device are simultaneously put into use, and the centralized energy consumption device can bear energy which needs to be consumed.
Specifically, the present embodiment is described by taking a specific system as an example. The DC rated voltage of the system is assumed to be 500kV, and the transmission rated power is 500 MW. Supposing that the earth fault of the receiving end alternating current single-phase system is detected at a certain moment, the direct current voltage rises at the moment, and the surplus power calculation formula is Ploss＝Psend-Pdc，PsendTransmitting power of 500MW, P to the current DC systemdcThe actual power of the receiving end converter station is about 330MW during the fault period, and the surplus power is about 170MW at the moment, Ploss/Psend<2/3, only the distributed energy consumption devices are needed to be put in, and the number of the energy consumption submodules is determined by the surplus power; supposing that a three-phase earth fault of a receiving end alternating current system occurs at a certain moment, the transmitting section transmits power of 500MW at the moment, the receiving end receives power of 0MW, surplus power generated at the moment is 500M, and P is obtained at the momentloss/Psend>2/3, the distributed energy consuming devices are used for stabilizing the DC voltage, and the centralized energy consuming devices are used for consuming surplus power.
The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention will still fall within the protection scope of the technical solution of the present invention.
Claims (7)
1. A control method of a hybrid energy consumption device is characterized by comprising a centralized energy consumption device and a distributed energy consumption device which are connected in parallel at a direct current line end; the centralized energy consumption device and the distributed energy consumption device can be put into use independently or simultaneously; when the voltage of the direct current line is higher than a preset value, preferentially selecting to put into the distributed energy consumption device; when the distributed energy consumption device can not completely consume the redundant energy, the centralized energy consumption device is simultaneously put into use.
2. The method as claimed in claim 1, wherein the centralized energy consuming device comprises a branch energy consuming module and a resistance energy consuming module, and the branch energy consuming module comprises at least one sub energy consuming module connected in series in the same direction.
3. The method as claimed in claim 1, wherein the distributed energy consuming apparatus comprises a plurality of voltage-sharing energy consuming modules, and the voltage-sharing energy consuming modules are connected in series.
4. The method as claimed in claim 1, wherein the designed rated power of the distributed consumer is greater than 2/3 rated power of the system, and the designed rated power of the centralized consumer is greater than 1/3 rated power of the system.
5. The method for controlling a hybrid energy consuming device according to any one of claims 1 to 4, comprising the steps of:
step S1: real-time detection of DC line voltage UdlWhen the receiving end AC system is in fault, the voltage of the DC line rises, and surplus power P consumed by the energy consumption device is calculatedloss；
Step S2: when the DC voltage U is detecteddlWhen the operation threshold value is increased and is larger than the action threshold value of the distributed energy consumption device, the distributed energy consumption device is put into the distributed energy consumption device according to the surplus power;
step S3: judgment of PlossRated power P of system0In relation to each other, if Ploss/P0<2/3, only the distributed energy consumption devices need to be put into use; if Ploss/P0>2/3, the distributed energy consuming devices and the centralized energy consuming devices are simultaneously put into operation.
6. The method as claimed in claim 5, wherein the distributed energy consuming device is pre-charged when the dc line voltage is normal, and the distributed energy consuming device is in a hot standby state after the pre-charging is completed.
7. The control method of a hybrid energy consumption device as claimed in claim 5, wherein when a single-phase fault occurs in the receiving ac grid, only the distributed energy consumption device is activated; when an alternating current two-phase fault or a three-phase fault occurs in a receiving end alternating current power grid, the distributed energy consumption device and the centralized energy consumption device are simultaneously put into use.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010049754.1A CN111244999B (en) | 2020-01-16 | 2020-01-16 | Control method of hybrid energy consumption device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010049754.1A CN111244999B (en) | 2020-01-16 | 2020-01-16 | Control method of hybrid energy consumption device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111244999A CN111244999A (en) | 2020-06-05 |
| CN111244999B true CN111244999B (en) | 2022-07-05 |
Family
ID=70874662
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010049754.1A Active CN111244999B (en) | 2020-01-16 | 2020-01-16 | Control method of hybrid energy consumption device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111244999B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109787264A (en) * | 2018-11-22 | 2019-05-21 | 詹长江 | A kind of centralization energy-consuming device and its control method |
| CN109861269A (en) * | 2019-03-29 | 2019-06-07 | 西安许继电力电子技术有限公司 | A kind of the switching control system and method for distributed DC energy-consuming device |
| CN110224423A (en) * | 2019-05-13 | 2019-09-10 | 南方电网科学研究院有限责任公司 | A kind of flexible direct current energy-consuming device and its circular current control method |
| CN110233488A (en) * | 2019-04-16 | 2019-09-13 | 清华大学 | A kind of more level concentration discharging circuits of unidirectional full-bridge modulesization |
| CN110571782A (en) * | 2019-07-31 | 2019-12-13 | 全球能源互联网研究院有限公司 | energy control circuit and method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DK2569843T3 (en) * | 2010-05-11 | 2014-04-22 | Abb Technology Ag | PLANT FOR TRANSMISSION OF HIGH VOLTAGE DC Current INCLUDING OVERVOLTAGE PROTECTION |
-
2020
- 2020-01-16 CN CN202010049754.1A patent/CN111244999B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109787264A (en) * | 2018-11-22 | 2019-05-21 | 詹长江 | A kind of centralization energy-consuming device and its control method |
| CN109861269A (en) * | 2019-03-29 | 2019-06-07 | 西安许继电力电子技术有限公司 | A kind of the switching control system and method for distributed DC energy-consuming device |
| CN110233488A (en) * | 2019-04-16 | 2019-09-13 | 清华大学 | A kind of more level concentration discharging circuits of unidirectional full-bridge modulesization |
| CN110224423A (en) * | 2019-05-13 | 2019-09-10 | 南方电网科学研究院有限责任公司 | A kind of flexible direct current energy-consuming device and its circular current control method |
| CN110571782A (en) * | 2019-07-31 | 2019-12-13 | 全球能源互联网研究院有限公司 | energy control circuit and method |
Non-Patent Citations (1)
| Title |
|---|
| Energy Diverting Converter Topologies for HVDC Transmission Systems;MANEIRO J等;《2013 15th European Conference on Power Electronics and Applications (EPE)》;20130906;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111244999A (en) | 2020-06-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101345419B (en) | Series voltage quality regulator and fast investment and cutting method | |
| Jovcic et al. | Power flow control in DC transmission grids using mechanical and semiconductor based DC/DC devices | |
| CN110867884B (en) | Energy consumption module, offshore wind power flexible direct current outgoing system and fault ride-through strategy | |
| CN112886550B (en) | MMC flexible direct-current power grid self-adaptive fault clearing method based on source network coordination | |
| EP1540792A1 (en) | Active power filter apparatus with reduced va rating for neutral current suppression | |
| WO2023151607A1 (en) | Flexible direct current power transmission voltage source converter valve test method and power supply device | |
| CN105703370B (en) | Unified power flow controller combining series compensation and current converter | |
| CN112269152A (en) | Transformer and converter valve charging test circuit and method | |
| Kale et al. | Integration of proactive hybrid circuit breaker with current flow controller for bipolar HVDC grid | |
| CN111244999B (en) | Control method of hybrid energy consumption device | |
| CN117595349A (en) | Efficient medium-voltage alternating current interconnection device and control method thereof | |
| CN110571815B (en) | Controllable unloading module based on resistance-capacitance device, circuit and control method | |
| CN105680453B (en) | Improved parallel hybrid unified power flow controller | |
| Villa et al. | Coordination of active current limiters and hybrid circuit breakers for a MVDC link meshing MVAC distribution grids | |
| CN115714404A (en) | Commutation soft switching system for governing current unbalance of power distribution network and evaluation method | |
| CN115242109A (en) | Low-proportion full-bridge hybrid MMC topology suitable for direct-current fault removal and control strategy thereof | |
| CN114266134A (en) | Economical efficiency improving system for offshore wind power multi-terminal flexible direct-current power transmission energy consumption device | |
| Manikandan et al. | Power quality compensation using SMES coil with FLC | |
| CN213517510U (en) | Transformer and converter valve charging test circuit | |
| Wu et al. | Improved hybrid HVDC circuit breaker with power flow control capability for HVDC grids | |
| EP3890174A1 (en) | Converter apparatus and assembly, reactive power compensation apparatus, and converter thereof, and control method therefor | |
| Habibinia et al. | Study of inverter and rectifier substations islanding fault in HVDC system, and comparison between different control-protective methods | |
| Dali et al. | Short-circuit fault analysis and protection of stand-alone AC and DC microgrids | |
| CN211830132U (en) | Line icing eliminating device for pumped storage station | |
| CN113162100B (en) | Control method and device for hybrid cascade direct current transmission system and electronic equipment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |