Views: 0 Author: Site Editor Publish Time: 2025-03-14 Origin: Site
With the wide application of photovoltaic system, the harmonic problem caused by it is also increasingly concerned. Harmonics will not only affect the operating efficiency of the photovoltaic system itself, but also have a negative impact on the power quality of the grid, resulting in equipment overheating, power factor reduction, relay protection misoperation and other problems. In order to effectively solve this problem, this article will introduce how to use ARK's power quality products to deal with the harmonics generated after the installation of photovoltaic.
The inverter in photovoltaic system is the main harmonic source. The inverter generates harmonic current in the process of converting direct current to alternating current. In addition, other nonlinear loads in photovoltaic systems, such as chargers, LED lighting, etc., can also produce harmonics. These harmonics will spread through the power grid and affect the stability and power quality of the entire power system.
1. Equipment overheating and damage: Harmonic current will cause additional heat loss in transformers, cables, switchgear, etc., resulting in equipment overheating, shortening equipment life, and increasing the risk of failure.
2. Power factor reduction: Harmonics will affect the power factor, reducing the transmission efficiency of the distribution system, increasing the loss of electric energy, resulting in an increase in the cost of electricity.
3. Relay protection misoperation: Harmonics may cause the misoperation or refusal of the relay protection device, affecting the safe operation of the power system, resulting in production interruption.
4. Power quality decline: harmonic pollution will cause voltage waveform distortion, affect the quality of power supply, and interfere with the normal operation of sensitive equipment (such as precision instruments, medical equipment, etc.).
APF active filter
APF active power filter is an effective device to solve the harmonic problem of photovoltaic system. Taking ARK's AHF series as an example, its working principle is as follows:
1. Current detection: The external current transformer (CT) detects the load current in real time and transmits the signal to the internal digital signal processor (DSP).
2. Harmonic analysis and compensation current calculation: DSP uses advanced logic control algorithm and fast Fourier transform (FFT) to decompose the load current into active power and reactive power parts, and quickly and accurately calculate the harmonic content. The DSP then sends a pulse width modulation (PWM) signal to the internally insulated gate bipolar transistor (IGBT) driver board.
3. Compensation current generation: The IGBT driver board controls the switching frequency of IGBT according to the PWM signal, and generates compensation current opposite to the harmonic current phase on the inverter sensor.
4. Harmonic offset: the compensation current and harmonic current cancel each other in the system, so as to purify the grid current and reduce the adverse impact of harmonics on the equipment and the grid.
Advantages of AHF in photovoltaic systems:
- Efficient harmonic control: AHF can quickly respond to harmonic changes in the system, effectively compensate for the second to 50 harmonics, and the compensation rate is greater than 92%, significantly reducing harmonic content and improving power quality.
Improve equipment efficiency and longevity: By reducing the risk of equipment overheating and failure due to harmonics, AHF helps to extend the service life of transformers, cables and other equipment and reduce maintenance costs.
- Power factor optimization: AHF can compensate reactive power while controlling harmonics, improve power factor, reduce electricity costs, and improve the overall efficiency of the distribution system.
- Intelligent and flexible: with intelligent control function, compensation policy can be automatically adjusted according to the change of system load. And the installation method is flexible, there are a variety of options such as wall-mounted and rack-type, to adapt to the spatial layout of different photovoltaic systems and distribution rooms.
- Reliability and stability: As a high-quality power equipment, AHF performs well in a variety of industrial and commercial environments, ensuring the stable operation of photovoltaic systems.
SVG static VAR generator
SVG static reactive power generators also play an important role in photovoltaic systems. Taking ARK's SVG series as an example, it works as follows:
1. Reactive power detection and compensation: SVG generates the corresponding reactive current in real time by detecting the reactive power demand in the system to support and adjust the grid voltage.
2. Harmonic control ability: SVG can not only provide reactive power compensation, but also has a certain harmonic control ability, which can compensate for a specific number of harmonics and further improve power quality.
Advantages of SVG in photovoltaic systems:
- Fast response: The response time of SVG is less than 10 milliseconds, which can quickly provide reactive power support and maintain the stability of the grid voltage.
- Efficient compensation: reactive power compensation rate is greater than 95%, effectively improve the power factor, reduce power loss.
- Modular design: SVG adopts modular design to facilitate installation and maintenance, and can flexibly configure capacity according to actual requirements.
- Strong adaptability: suitable for a variety of photovoltaic systems and power grid environments, able to operate stably under complex power conditions.
ARK's power quality products are suitable for all types of photovoltaic systems, including but not limited to:
- Distributed photovoltaic power stations: photovoltaic systems installed on the roofs of factories, commercial buildings, residential buildings, etc., have obvious harmonic control needs.
- Centralized photovoltaic power stations: large-scale photovoltaic power stations have higher requirements for power quality and equipment stability.
Photovoltaic energy storage systems: Photovoltaic systems combined with energy storage devices require more efficient power quality management and harmonic governance.
The harmonics caused by PV installation have a significant impact on the stable operation and equipment life of the power system. By using ARK's power quality products, such as APF active filters and SVG static reactive power generators, harmonics can be effectively controlled, power quality can be improved, and efficient and stable operation of photovoltaic systems can be guaranteed. Choosing the right power quality products is not only the protection of photovoltaic investment, but also the contribution to the healthy operation of the entire power system.