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A Control Strategy of Dynamic Voltage Stabilizer for Distribution Network

A dynamic voltage and control strategy technology, applied in the direction of AC network voltage adjustment, AC network flicker reduction, etc., can solve the problems of limiting the dynamic response speed of DVR, weakening the robustness of equipment, and being unable to meet the compensation voltage without static error tracking. Achieve the effect of improving the transient response characteristics, solving the complex calculation of coordinate changes, and suppressing the underdamping effect

Active Publication Date: 2017-05-03
STATE GRID CORP OF CHINA +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Among the control strategies widely used in DVR at present, the traditional AC voltage outer loop proportional control strategy is the easiest to implement, and the transient response speed is fast, but it cannot meet the requirements of compensation voltage without static error tracking; the proportional integral (PI) based on coordinate transformation ) control strategy can realize the static-difference-free control of DVR output voltage, but the complexity of coordinate transformation calculation greatly limits the dynamic response speed of DVR and weakens the robustness of the device

Method used

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  • A Control Strategy of Dynamic Voltage Stabilizer for Distribution Network
  • A Control Strategy of Dynamic Voltage Stabilizer for Distribution Network
  • A Control Strategy of Dynamic Voltage Stabilizer for Distribution Network

Examples

Experimental program
Comparison scheme
Effect test

Embodiment example 1

[0047] Such as image 3 with 4 The PSCAD\EMTDC simulation diagrams of two different scenarios of three-phase symmetrical voltage drop and three-phase asymmetrical voltage drop under the dynamic voltage stabilizer without phase jump are shown, as shown Figure 5 The PSCAD\EMTDC simulation diagram of the asymmetrical voltage drop under the phase jump is shown as shown to further describe the specific working process of the present invention. Since the dynamic voltage stabilizer uses three single-phase structures, the three phases are independent control, so only the single-phase operation process is given, and at the same time image 3 , Figure 4 with Figure 5 The simulated waveform in the first scenario of the three different scenarios is taken as an example for detailed description.

[0048] Simulation time: 0.52s, IGBT switching frequency 3.2kHz, system frequency 50Hz; fault start time 0.305s, fault duration 0.2s; fault type: three-phase symmetrical voltage drop 50%.

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Embodiment example 2

[0053] In order to further verify the engineering practicability of this device, an experimental platform composed of DVR, asynchronous motor and voltage drop generator was established, such as Image 6 with 7 The expanded waveforms at the beginning and end of grid voltage sag are given.

[0054] Source 1 is the grid voltage, source 2 is the output voltage of the DVR, and source 3 is the load terminal voltage; during operation, the grid voltage drops with a time span of about 1s, and its peak value drops from 300V to 110V, and the voltage drop occurs After that, the DVR responds quickly and maintains the load terminal voltage at the normal level.

[0055] The experimental waveforms confirmed that when the grid voltage dropped to 30% of the rated value, the DVR completed the response within 2ms, and there was no voltage oscillation phenomenon easily caused by the system under-damping, the dynamic characteristics were good, and the compensation effect was verified after stabili...

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Abstract

The invention discloses a dynamic voltage stabilizer of a power distribution network. The dynamic voltage stabilizer comprises an isolation transformer, a single-phase uncontrolled rectifier bridge, a direct current bus capacitor, a single-phase H-bridge inverter, a low-pass inductance-capacitance filter and a by-pass switch, wherein the primary side of the isolation transformer is connected with a power grid, the secondary side of the isolation transformer is connected with the alternating current side of the single-phase uncontrolled rectifier bridge, the single-phase uncontrolled rectifier bridge, the direct current bus capacitor and the single-phase H-bridge inverter are connected in parallel, the alternating current side of the single-phase H-bridge inverter is connected with the low-pass inductance-capacitance filter, and the by-pass switch is connected with a capacitor of the low-pass inductance-capacitance filter. The invention also discloses a control strategy of the dynamic voltage stabilizer. According to the dynamic voltage stabilizer of the power distribution network, a half-cycle Posicast control method is introduced in the traditional proportional resonant control, DVR (Discharge Voltage Regulator) dampness is increased, large high-frequency gain is achieved, the sensitivity of the system to noise is reduced, the underdamping effect caused by the low-pass inductance-capacitance filter can be effectively inhibited and the transient response characteristic of the DVR is greatly improved.

Description

technical field [0001] The invention relates to a distribution network dynamic voltage stabilizer and its control strategy, and belongs to the technical fields of flexible AC power transmission and distribution of power systems and power electronics. Background technique [0002] With the development of modern power systems, the power quality problems caused by the connection of a large number of nonlinear loads in the power grid, capacitor switching, motor start and stop, and various system failures have attracted more and more attention. For power grid users, power Quality problems may lead to the failure or malfunction of its electrical equipment, causing huge economic losses and potential safety hazards. [0003] Among many power quality control devices, dynamic voltage stabilizer (DVR), as a typical representative of series devices, is the most direct and economical power electronic device to solve the problem of voltage sag, and has been widely used in distribution net...

Claims

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Application Information

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IPC IPC(8): H02J3/12
CPCH02J3/002H02J3/12
Inventor 贺永胜颜盛军李捷王冬杨永标周静黄莉陈璐王金明
Owner STATE GRID CORP OF CHINA
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