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What kind of load is prone to generating leading power reactive power?
Leading power factor conditions typically occur when a system has capacitive loads or a surplus of capacitive reactance over inductive reactance. Capacitive loads store energy in an electric field, unlike inductive loads that store energy in a magnetic field. When these loads are present in an electrical system, they can cause the current to lead the voltage, resulting in a leading power factor.
Common types of loads that can generate a leading power factor include:
1. Capacitors and Capacitor Banks: These are specifically designed to provide leading reactive power. They are often used in power factor correction schemes to counteract the effects of inductive loads.
2. Electronic Loads: Modern electronic equipment, such as computers, LED lighting, and variable frequency drives (VFDs), can exhibit capacitive characteristics under certain operating conditions, contributing to a leading power factor.
3. DC Machines: When operating as generators, especially when lightly loaded or running on open circuit, DC machines can produce a leading power factor.
4. Certain Types of Transformers: Under specific loading conditions, some transformers can operate with a leading power factor.
5. Overcompensation: If an electrical system has been overcompensated with capacitors for power factor correction, it may result in a leading power factor.
6. High Voltage Direct Current (HVDC) Systems: In some HVDC applications, the converter stations can operate with a leading power factor, particularly when using thyristor-controlled rectifiers in inverter mode.
7. Motor Generators (MG) Sets: MG sets can be configured to operate in a leading power factor mode, especially when the generator is overexcited.
SVG, or Static Var Generator, is used to improve the power factor in electrical systems by compensating for reactive power. Reactive power (Q) is the component of power that does not do any work but instead oscillates between the source and load. It's measured in Volt-Amperes Reactive (VARs). The power factor is the ratio of real power (P) to apparent power (S), which is the vector sum of real and reactive power.
When the power factor is lagging (common in industrial settings due to inductive loads like motors and transformers), the system has to supply more current than necessary, leading to higher losses and reduced efficiency. An SVG can help correct this by generating or absorbing reactive power as needed.
Here’s how an SVG works to compensate for leading power factor:
1. Detection of Power Factor: The SVG monitors the incoming voltage and current to determine the phase difference between them, which indicates the power factor.
2. Generation of Reactive Power: If the system detects a lagging power factor (current lags behind voltage), the SVG will generate leading reactive power. This means it will absorb lagging VARs from the system, effectively shifting the current closer to being in phase with the voltage.
3. Absorption of Reactive Power: Conversely, if there is a leading power factor (current leads the voltage), indicating that the system is generating more reactive power than needed, the SVG will absorb this excess leading reactive power, thus reducing the leading power factor towards unity.
4. Adjustment and Optimization: The SVG continuously adjusts its output to match the system’s requirements, ensuring that the power factor remains close to unity, minimizing losses and improving system efficiency.
In essence, the SVG acts as a dynamic reactive power source that can both generate and absorb reactive power, depending on the needs of the system. This flexibility allows it to effectively manage power factor issues in real-time, making it a valuable tool for maintaining efficient and stable electrical systems.
Site conditions
The site is located in Hangzhou Asian Games Village.The project has more than 20 power distribution rooms. Due to the main load being fire-fighting facilities, which are generally not started, the transformers almost all operate without load, and the cable length is long, resulting in capacitive reactive power at both the high and low voltage sides, which cannot be compensated by the capacitor. Therefore, the power factor is low (0.2-0.5), and there is a risk of fines.
Solutions
According to the on-site situation analysis, it is recommended to install SVG on the low-voltage side for reactive compensation. SVG compensates capacitive/inductive reactive power generated by the load in real time by sampling low-voltage side current data.
At the same time, for the reactive power generated by transformers and cables, we can set a reactive power correction amount for SVG to compensate for the reactive power generated by transformers and cables while compensating for the reactive power on the low-voltage side. After calculation, the reactive power generated by the transformer is around 20kvar. Therefore, it is recommended to configure a 100kvar SVG module to compensate for the reactive power of the load while also taking into account the reactive power compensation of the transformer and cable.
Due to the existing reactive compensation capacitor cabinet on site, attention must be paid to the installation location of the primary line access point and the transformer during the installation of SVG to ensure that the SVG and capacitor cabinet can work in coordination. Due to the fast response speed of SVG, the sampling of SVG must include the current of the capacitor cabinet, and the sampling of the capacitor cabinet cannot include the current of SVG.
YTPQC-SVG
SVG (Static Var Generator) is a type of power electronic device used to compensate for reactive power in a power system. It works by generating or absorbing reactive power, depending on the needs of the system. The SVG can be used to compensate for both capacitive and inductive reactive power, but it is most commonly used to compensate for capacitive reactive power. This is because capacitive loads tend to draw more current than inductive loads, resulting in an increase in the total reactive power demand. By using an SVG, the amount of capacitive reactive power can be reduced, allowing the system to operate more efficiently and reducing losses.
Any technical inquiry about Static Var Generator(SVG) or Active Harmonic Filter(AHF), contact with us sales@yt-electric.com
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