The specific role of SVG in photovoltaic power stations
Oct 22,2024
SVG (Static Var Generator) plays a vital role in photovoltaic power stations. It significantly improves the energy efficiency, grid stability and power quality of photovoltaic power stations by quickly and accurately providing or absorbing reactive power.
SVG is an advanced reactive power compensation device that uses power electronics technology to achieve rapid regulation of grid reactive power. It is mainly composed of a detection module, a control operation module and a compensation output module. It controls the reactor connected to the AC side through a power electronic converter (such as IGBT) and adjusts the reactive output of the reactor in real time according to the real-time reactive demand of the load to achieve the purpose of compensating the reactive power of the system.
Specific role of SVG in photovoltaic power stations:
1. Improve power factor
Power factor is an important indicator for measuring power quality and is directly related to the utilization efficiency of power and the operating cost of the power system. In photovoltaic power stations, since the power output of the photovoltaic array is volatile, this fluctuation includes not only changes in active power, but also changes in reactive power. SVG can detect the voltage and current status of the power grid in real time, quickly compensate for reactive power, and make the power factor of the power station close to 1, that is, to achieve "unity power factor". This can maximize the transmission of effective power, reduce line losses and equipment heat losses caused by reactive power flow, and improve the overall energy efficiency of the photovoltaic power station.
2. Reduce losses
When there is reactive power in the power system, it will cause the current to increase, resulting in more line losses and equipment heat losses. SVG reduces these losses by effectively controlling reactive power and reducing the current level in the system. This not only improves the economic benefits of photovoltaic power stations, but also reduces the negative impact on the environment.
3. Voltage stability
SVG has a voltage regulation function, which can adjust the grid voltage by adjusting the phase and amplitude of the current according to the voltage change of the grid. When the grid voltage is too high, SVG can absorb the reactive power of the grid and reduce the grid voltage; when the grid voltage is too low, SVG can inject reactive power and increase the grid voltage. This voltage regulation capability helps to reduce voltage fluctuations caused by grid load changes, maintain voltage stability, and ensure the safe and stable operation of photovoltaic power stations and grids.
4. Harmonic suppression
SVG usually has the function of filtering harmonics, which can reduce harmonic pollution in the power grid. Harmonics are one of the common power quality problems in the power system. It can cause problems such as heating, vibration, increased noise, and even damage the equipment. By precisely controlling its output current, SVG can effectively suppress harmonics in the power grid, improve power quality, and protect the safe operation of power equipment and loads.
5. Improve the stability of the power grid
In large-scale grid-connected photovoltaic power stations, there are problems of sharp fluctuations in power load and sudden changes in current, which pose a challenge to the stability of the power grid. SVG can quickly respond to changes in voltage and reactive power of the power grid, and maintain the stable operation of the power grid by adjusting the injection or absorption of reactive power. It can effectively suppress voltage fluctuations and voltage sags in the power grid, improve the stability and reliability of the power grid, and ensure the normal operation of photovoltaic power stations.
6. Optimize the quality of grid access
As an important part of renewable energy, the grid-connected performance of photovoltaic power stations directly affects the overall quality and stability of the power grid. SVG significantly optimizes the grid-connected performance of photovoltaic power stations by improving the power factor of photovoltaic power stations, reducing losses, stabilizing voltage and suppressing harmonics, so that photovoltaic power stations can be better integrated into the power grid system and provide stable and high-quality electricity for the power grid.
Compared with traditional reactive compensation devices (such as capacitors and reactors), SVG has the following advantages:
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Fast response: SVG can respond to changes in reactive power in milliseconds, while traditional devices respond slowly.
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Continuous regulation: SVG can achieve continuous regulation of reactive power without being restricted by step changes.
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Two-way regulation: SVG can not only provide reactive power, but also absorb excess reactive power from the power grid.
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Adaptability to harmonics: SVG can suppress system harmonics and improve power quality, while traditional devices may require additional harmonic control facilities.
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No overload protection required: SVG does not require overload protection due to excessive reactive power during operation, and is relatively more stable and reliable.
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Small footprint: Since SVG is based on power electronics technology, its size is smaller than traditional equipment, and its installation is more flexible and convenient.
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Low maintenance cost: SVG has lower maintenance cost compared with traditional reactive power compensation devices that require regular maintenance due to its simple semiconductor devices and control.
SVG plays an irreplaceable role in photovoltaic power stations. It significantly improves the energy efficiency and grid quality of photovoltaic power stations by improving power factor, reducing losses, stabilizing voltage, suppressing harmonics and improving grid stability. With the continuous development of the photovoltaic industry and the continuous improvement of grid requirements, the application of SVG will become more and more extensive, which is of great significance to promoting the development of photovoltaic power stations, especially large-scale photovoltaic power stations. For power system operators and photovoltaic power station investors, understanding and correctly applying SVG technology will help improve the economic and technical benefits of photovoltaic projects and achieve efficient use of green energy.
