CN-122001012-A - DC interconnection power distribution network optimal scheduling method based on converter control switching

CN122001012ACN 122001012 ACN122001012 ACN 122001012ACN-122001012-A

Abstract

The invention belongs to the technical field of power engineering. The direct current interconnection power distribution network optimal scheduling method based on converter control switching is used for solving the problems of power distribution network voltage out-of-limit, scheduling inefficiency and the like under the condition of high permeability of new energy, a photovoltaic-energy storage-VSC multi-level voltage stable supporting system is built by adopting VSC (voltage source controller) and VSC networking dual-mode cooperative control, dual-mode undisturbed switching is realized through virtual quantity calculation and proportion superposition, a trans-regional power mutual economy mechanism is built by means of a direct current channel, and a power purchase cooperative control system is built by combining time-of-use electricity prices. The invention realizes the collaborative optimization of voltage stabilization and economic dispatching, improves the new energy consumption capability, reduces the electricity purchasing cost of the upper power grid, and is suitable for the 'source-network-load-storage' collaborative dispatching scene.

Inventors

SHA ZHICHENG
HE YUHAN
YU FEI
WANG ZHUODI
Zhen Jiubao
LIU WEI
WANG ZENGHUI
WANG RUIQI
Gong dai
YANG ZHILI

Assignees

山东电力工程咨询院有限公司

Dates

Publication Date: 20260508
Application Date: 20260115

Claims (10)

1. The direct current interconnection power distribution network optimization scheduling method based on converter control switching is characterized by comprising the following steps of: Building a photovoltaic-energy storage-VSC cooperative multilevel voltage stable supporting system, dynamically adjusting reactive power output by a photovoltaic power station according to node voltage deviation, and providing self-adaptive reactive power compensation by an energy storage system based on voltage drop depth; When node voltage out-of-limit or power fluctuation exceeding a preset range is detected, virtual output voltage is generated for networking control based on the acquired data, so that output reference values of a network following control loop and a network constructing control loop are matched, smooth transition of VSC from the network following mode to the network constructing mode is realized, and active voltage or frequency support and inertia supplement are provided through virtual synchronous machine characteristics of the network constructing mode; A trans-regional power mutual-aid mechanism is established by means of direct current interconnection channels, surplus power of a new energy enrichment region is directionally transferred to a load center by utilizing active power regulation capability of a VSC, a daily charge and discharge plan of an energy storage system is formulated by combining photovoltaic and load prediction, and photovoltaic output deviation is compensated by regulating active power transmission of the VSC in real-time operation; Constructing a power purchase cooperative control mechanism, transmitting surplus power through the VSC in a photovoltaic power generation period and cooperatively storing and charging, preferentially calling energy storage and discharging in a load peak period, and introducing the surplus power to stabilize a power purchase peak value through the VSC when the energy storage power reaches an upper limit; When the system is restored to normal voltage and the power fluctuation accords with a normal threshold, virtual output current is generated for GFL control based on actual line parameters and PCC point operation data, smooth transition of the VSC from a networking mode to a following mode is realized, and continuous and optimal operation of the power distribution network is maintained.
2. The optimized dispatching method for the direct-current interconnected power distribution network based on the control switching of the converter according to claim 1, wherein, The reactive power regulation of the photovoltaic system adopts a voltage prediction-real-time tracking double-layer control mechanism, the voltage prediction generates a voltage reference value based on historical node voltage data and environmental factors, and the real-time tracking dynamically distributes reactive power according to the deviation between the actual node voltage and the voltage reference value so as to ensure the capacity required by tracking of the maximum power point.
3. The optimized dispatching method for the direct-current interconnected power distribution network based on the control switching of the converter according to claim 1, wherein, The self-adaptive compensation strategy of the energy storage system comprises the steps of presetting two voltage deviation thresholds, outputting reactive power according to a first response coefficient when the node voltage deviation does not exceed a first threshold, superposing basic compensation power output according to a second response coefficient when the voltage deviation is between the first threshold and a second threshold, outputting according to the maximum reactive capacity when the voltage deviation exceeds the second threshold, and compensating reactive power output by the energy storage system in a mode switching transition stage to compensate reactive power output fluctuation of a VSC so as to avoid voltage regulation gear interruption.
4. The optimized dispatching method for the direct-current interconnected power distribution network based on the control switching of the converter according to claim 1, wherein, Analyzing the space-time distribution difference of a node photovoltaic system and a load, breaking through radial operation constraint of a traditional alternating-current power distribution network through the bidirectional power controllable characteristic of VSC, and transferring surplus power of a photovoltaic enrichment area to a load center through a direct-current interconnection channel.
5. The optimized dispatching method for the direct-current interconnected power distribution network based on the control switching of the converter according to claim 1, wherein, The energy storage-VSC double-layer optimization strategy comprises the steps of making a charge-discharge plan of the node energy storage system based on a secondary sunlight photovoltaic output predicted value and a load predicted value in a day-ahead stage and taking electricity purchasing cost as a target, and dynamically adjusting active transmission power of the VSC when deviation is generated between actual photovoltaic output and the predicted value in a real-time stage so as to offset the deviation and reduce unplanned charge-discharge of the energy storage system.
6. The optimized dispatching method for the direct-current interconnected power distribution network based on the control switching of the converter according to claim 1, wherein, The smooth transition adopts a mixed proportion control strategy, and a network following control loop and a network constructing control loop are enabled to operate in a closed loop at the same working point all the time through a virtual quantity calculation and proportion superposition mechanism, wherein the triggering condition of switching from the network following mode to the network constructing mode is that the node voltage is lower than 0.95pu or the power fluctuation is larger than a preset fluctuation threshold, and the triggering condition of switching from the network constructing mode to the network following mode is that the node voltage is between 0.98pu and 1.02pu and the power fluctuation is smaller than the preset fluctuation threshold.
7. The optimized dispatching method for the direct-current interconnected power distribution network based on the control switching of the converter according to claim 1, wherein, The network construction control is based on virtual inertia-excitation cooperative logic, synchronous generator rotor movement and excitation regulation characteristics are modeled through a virtual synchronous generator algorithm, virtual mechanical torque and electromagnetic torque deviation are transmitted into a rotor movement equation to generate virtual angular speed and power angle reference signals, an excitation regulation module dynamically corrects alternating-current side voltage reference values according to the power angle deviation, and modulation signals are generated to drive the converter after voltage outer ring and current inner ring processing.
8. The utility model provides a direct current interconnection distribution network optimization dispatch system based on transverter control switches which characterized in that includes: The voltage stabilizing support unit is configured to construct a photovoltaic-energy storage-VSC cooperative multi-level voltage stabilizing support system, the photovoltaic power station dynamically adjusts reactive power output according to node voltage deviation, and the energy storage system provides self-adaptive reactive power compensation based on voltage drop depth; The mode switching triggering unit is configured to acquire the voltage and current data of the PCC points of the power distribution network and actual line parameters in real time, generate virtual output voltage for networking control based on the acquired data when detecting that the node voltage is out of limit or the power fluctuation is out of a preset range, enable the output reference values of the networking control loop and the networking control loop to be matched, realize smooth transition of the VSC from the networking mode to the networking mode, and provide active voltage or frequency support and inertia supplement through the virtual synchronous machine characteristic of the networking mode; The power mutual-aid scheduling unit is configured to establish a cross-region power mutual-aid mechanism by means of a direct current interconnection channel, directionally transfer surplus power of a new energy enrichment region to a load center by utilizing the active power adjustment capability of the VSC, and formulate a daily charge and discharge plan of the energy storage system by combining photovoltaic and load prediction, and compensate photovoltaic output deviation by adjusting active power transmission of the VSC in real-time operation; The electricity purchasing cooperative peak clipping unit is configured to construct an electricity purchasing cooperative control mechanism, transmit surplus power through the VSC in a photovoltaic power generation period and cooperatively store energy for charging, preferentially invoke energy storage for discharging in a load peak period, and introduce the surplus power to stabilize an electricity purchasing peak value through the VSC when the energy storage power reaches an upper limit; And the recovery mode switching unit is configured to generate virtual output current for GFL control based on actual line parameters and PCC point operation data when the system is recovered to normal voltage and the power fluctuation accords with a normal threshold value, so that smooth transition from a network construction mode to a network following mode of the VSC is realized, and continuous and optimal operation of the power distribution network is maintained.
9. A computer device comprises a processor and a computer-readable storage medium; A processor adapted to execute a computer program; A computer readable storage medium having a computer program stored therein, which when executed by the processor, implements the dc interconnection power distribution network optimization scheduling method based on converter control switching as claimed in any one of claims 1 to 7.
10. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program adapted to be loaded by a processor and to perform the method for optimized scheduling of a dc-interconnected distribution network based on converter control switching according to any one of claims 1 to 7.

Description

DC interconnection power distribution network optimal scheduling method based on converter control switching Technical Field The invention relates to the technical field of power engineering, in particular to a DC interconnection power distribution network optimization scheduling method based on converter control switching. Background The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. At present, new energy equipment such as distributed photovoltaic equipment, energy storage equipment and the like is accessed into a power distribution network in a large scale, so that the power distribution network presents a complex form of source-network-load-storage multi-element coordination. However, the fluctuation and randomness of the new energy output easily cause problems of power distribution network node voltage out-of-limit, reverse power flow and the like, and the traditional power distribution network which relies on an on-load voltage regulating transformer or a voltage regulator has difficulty in meeting the voltage control requirement. Along with the progress of the power electronic technology, the alternating current-direct current hybrid power distribution technology is applied to the medium-low voltage distribution network in a test point due to the advantages of high capacity, low loss, convenience in novel source-load access and the like. Therefore, research and development of an AC/DC hybrid power distribution system and key technology thereof have important significance for enhancing flexible regulation and control capability of a power distribution network and pushing construction of a novel power system. The voltage source type converter (Voltage Source Converter, VSC) is used as core equipment for alternating current-direct current energy conversion and has active-reactive decoupling control capability, but the single control mode is difficult to meet the requirements of voltage stabilization and economic dispatch of the power distribution network. In the prior art, VSC adopts a grid following control mode, the voltage phase of a power grid is passively followed, passive network voltage cannot be actively supported, partial researches are introduced into the grid following control mode to simulate the characteristics of a synchronous generator, but dynamic switching mechanisms and multi-resource collaborative optimization strategies of the grid following control mode are lacked, and multi-target scheduling requirements of a power distribution network in a complex operation scene are difficult to deal with. Disclosure of Invention In order to solve the defects of the prior art, the invention provides a direct current interconnection power distribution network optimization scheduling method based on converter control switching, which designs a VSC and network/network construction dual-mode cooperative control strategy, establishes a topology-control-scheduling three-in-one optimization system and realizes cooperative optimization of power distribution network voltage stable support and economic scheduling. In order to achieve the above purpose, the present invention adopts the following technical scheme: In a first aspect, the invention provides an optimized dispatching method for a direct-current interconnected power distribution network based on converter control switching. A DC interconnection power distribution network optimization scheduling method based on converter control switching comprises the following steps: Building a photovoltaic-energy storage-VSC cooperative multilevel voltage stable supporting system, dynamically adjusting reactive power output by a photovoltaic power station according to node voltage deviation, and providing self-adaptive reactive power compensation by an energy storage system based on voltage drop depth; When node voltage out-of-limit or power fluctuation exceeding a preset range is detected, virtual output voltage is generated for networking control based on the acquired data, so that output reference values of a network following control loop and a network constructing control loop are matched, smooth transition of VSC from the network following mode to the network constructing mode is realized, and active voltage or frequency support and inertia supplement are provided through virtual synchronous machine characteristics of the network constructing mode; A trans-regional power mutual-aid mechanism is established by means of direct current interconnection channels, surplus power of a new energy enrichment region is directionally transferred to a load center by utilizing active power regulation capability of a VSC, a daily charge and discharge plan of an energy storage system is formulated by combining photovoltaic and load prediction, and photovoltaic output deviation is compensated by regulating active power transmission of the VSC in real-time operation; Construct