A comprehensive guide for machine builders and plant operators on improving the power factor and reducing energy losses.
What is the power factor and why is it important for my industrial plant?
Der Power factor (cos φ) is the ratio of active power to apparent power. A high power factor means that your plant uses energy efficiently, which leads to lower electricity costs and a milder burden on your resources . For manufacturing companies, it is crucial for optimizing operating costs.
How does a low power factor affect my operating costs?
A low power factor leads to a higher power draw for the same active power. This causes greater line losses, can lead to overloading of cables and transformers and energy providers often charge additional costs for reactive power billed. For example, a cos φ of 0.75 instead of 0.95 can incur additional costs of €2,500 .
What are the main causes of a low power factor in industrial plants?
Main causes include inductive loads such as motors, transformers, ballast of fluorescent lamps, and welding machines. These require reactive power to build their magnetic fields, which leads to phase shift between current and voltage and thus results in a low power factor.
How can I improve the power factor in my plant?
The most common method is reactive power compensation using capacitors. These can be installed centrally, decentrally, or as automatic control systems to balance the inductive reactive power and optimize the power factor.
What target value should the power factor have?
An ideal power factor is 1. In practice, a value of cos φ ≥ 0.9 to 0.95 (inductive) is aimed for. Many energy providers require a minimum value (often 0.9) to avoid penalty fees for excessive reactive power.
Does ATEK Drive Solutions offer solutions for optimizing the power factor?
ATEK Drive Solutions focuses on highly efficient drive components such as modern servo motors and gear boxes. The use of energy-efficient motors and correctly sized drives already contributes to an improved systemic power factor . For specific compensation systems, we are happy to advise you within the context of our drive solutions.
What is the difference between power factor and efficiency?
Der Power factor (cos φ) describes the ratio of active power to apparent power, that is, how effectively apparent power is converted into usable work. The efficiency (η) , on the other hand, describes the ratio of output usable power to input active power, meaning how much of the input active power is actually available as the desired form of energy (e.g., mechanical). Both are important for energy efficiency but describe different aspects..
How is the power factor calculated?
The power factor (cos φ) is calculated by dividing the active power (P) in kilowatts (kW) by the apparent power (S) in kilovolt-amperes (kVA): cos φ = P / S. In purely sinusoidal curves, it corresponds to the cosine of the phase shift angle φ between voltage and current.
Der Power factor (cos φ) is a measure of energy efficiency and is calculated as active power divided by apparent power (P/S). A value close to 1 is optimal and lowers energy costs as well as the burden on the systems.
A low power factor, often caused by inductive loads such as motors, leads to higher power draw, energy losses and can shorten the service life of resources by up to 15% and cause significant additional costs.
By reactive power compensation, for example, using capacitors, the power factor can be actively improved to target values of over 0.95. This can reduce costs for reactive power by up to 90% and increase overall efficiency.Discover how to optimize the power factor in your industrial drive systems, reduce energy costs, and extend the lifespan of your plants. This article provides practical insights and solutions.
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Understanding the power factor : Building foundations for greater energy efficiency.
An optimal power factor, often referred to as power factor , increases the efficiency of industrial plants and lowers energy costs. This article explains the understanding, improvement, and strategies to utilize the potential of drive technology with regard to the power factor.
What is the power factor actually?
An unfavorable cos φ, a measure of energy transmission efficiency, closely related to the power factor, can cause high electricity bills (e.g., €2,500 additional costs with a cos φ of 0.75 instead of 0.95). Understanding this important parameter, the power factor, is crucial.
Why is this value so crucial?
A low cos φ (e.g., 0.8 instead of the targeted 0.95) places a greater load on resources, increases heat losses, and can shorten the lifespan by up to 15%. Therefore, optimizing the power factor thus promotes the longevity of the plants. Understanding the power factor cos phi is an important first step toward improving the power factor.
The role in modern drive technology
Der power factor significantly influences modern drive solutions, such as those offered by ATEK Drive Solutions GmbH. An optimized cos φ is relevant for overall performance in complex systems. An integrated correction of the power factor can reduce downtime (by up to 10%). The power factor is therefore an integral part of high-quality drive solutions. Der Energy-saving calculator helps quantify potential savings through an improved power factor.
Den power factor define precisely and calculate correctly.
The formula: Active power divided by apparent power
Der power factor, expressed as cos φ, is calculated from active power (P) divided by apparent power (S). An ideal power factor is 1. For instance, a 10 kW motor with a cos φ of 0.8 requires 12.5 kVA of apparent power. This formula helps understand energy efficiency and the significance of the power factor.
- The basic formula of the power factor (cos φ), also power factor known, is defined as the ratio of active power (P) to apparent power (S): cos φ = P/S.
- An ideal power factor is 1, which means that all apparent power is utilized as active power and the power factor is optimal.
- Active power (P) is the actual power that performs mechanical work or generates heat; it is the numerator in the fraction of the power factor.
- Reactive power (Q) is necessary for generating magnetic or electric fields and oscillates between producers and consumers without directly contributing to active power.
- Apparent power (S) is the geometric sum of active and reactive power and represents the total load on the grid (S² = P² + Q²); it is the denominator in the fraction of the power factor.
- A high proportion of reactive power leads to a low power factor, thus an unfavorable power factor, resulting in inefficient energy transmission.
- The goal is to minimize reactive power to optimize the power factor and bring it close to 1 to increase efficiency. power factor Active, reactive, and apparent power in detail
Active power (P) performs work and is crucial for good
Wirkleistung (P) verrichtet Arbeit und ist entscheidend für einen guten power factor. Reactive power (Q) builds magnetic fields. Apparent power (S) is the sum (S²=P²+Q²). A high reactive power Q deteriorates the cos φ, hence the power factor. The goal is to minimize Q to improve the power factor.Calculate apparent power.
A practical calculation example for the power factor
A motor has a power of 4kW and a power factor (cos φ) of 0.85. The apparent power S calculates to S = 4kW / 0.85 = 4.706 kVA. The resulting reactive power is about 2.48 kVAR. This additional apparent power, caused by a less-than-optimal power factor, burdens the grid and can incur costs.Power calculation basics help to better understand the power factor recognize a lowand minimize its consequences. power factor Inductive loads as the main causes of a poor power factor
Inductive loads such as motors and transformers are the main causes of a low cos φ and thus an unfavorable
, as they require reactive power to build their magnetic fields. Over 70% of industrial loads are inductive and negatively affect the power factor. power factor Understanding the types of loads is relevant for optimizing the power factor. Das Verständnis der Lastarten ist für die Optimierung des Wirkleistungsfaktors relevant. More about Cos φ in three-phase current and its relation to the power factor.
The consequences of a low power factor: From heat losses to additional costs
A low power factor (e.g., a cos φ of 0.7) increases the overall current demand and leads to greater thermal losses in wires and equipment. It overloads transformers and cables and can shorten their lifespan. Energy providers often charge additional costs for reactive power that accrue with a poor power factor . These costs can accumulate to hundreds or thousands of euros annually, all due to a suboptimal power factor.
Capacitive loads: The counterpart and their role for the power factor
Less frequently, capacitive loads (e.g., from long cables or incorrectly sized compensation capacitors) are the cause of a problematic power factor. Most often, the goal is to compensate for the prevailing inductive nature of the loads to improve the power factor . A precise consumer analysis, including a reactive power measurement, reveals the causes of a poor power factor.
Den power factor actively improve by targeted reactive power compensation.
The principle of reactive power compensation to improve the power factor
Reactive power compensation is a key method to improve the cos φ and thus the power factor This involves connecting capacitors in parallel to the inductive loads. They provide capacitive reactive power and thus compensate for the inductive reactive power. The goal is to achieve a power factor (cos φ) of over 0.95. This relieves the network, the lines, and reduces energy losses, which directly optimizes the active power factor.
- Basic principle: Use of capacitors to provide capacitive reactive power to increase the power factor to increase.
- Goal: Compensation of the inductive reactive power of consumers such as motors and transformers to achieve a better power factor to achieve.
- Target value: An improved power factor, ideally above 0.95, which corresponds to a very good power factor compensation.
- Types of compensation for optimizing the power factor: Central compensation (at the main distribution), group compensation, or individual compensation (directly at the consumer).
- Economics: The amortization of compensation systems for increasing the power factor often occurs in less than two years.
- Automatic control: Use of reactive power controllers that dynamically switch capacitor banks on or off to keep the power factor constantly optimal.
- Calculation: The required compensation power (Qc) to adjust the power factor is calculated with the formula Qc = P * (tan φ₁ – tan φ₂).
Central vs. decentralized compensation to optimize the active power factor
Compensation to improve the power factor can take place centrally (at the main distribution), as group compensation, or as individual compensation (directly at the consumer, e.g., in a 50kW motor, particularly effective). The payback time for measures to improve the power factor is often less than two years. The choice of strategy for optimizing the active power factor depends on the respective system structure.
Automatic control for dynamic loads and a stable active power factor
Automatic reactive power controllers are ideal for systems with fluctuating loads. They continuously measure the cos φ and switch capacitor banks on or off as needed to keep the power factor optimal. This can reduce costs for reactive power by up to 90%. Dynamic control is crucial for maintaining a consistently high active power factor and maximum efficiency. Also modern frequency converters can contribute to the improvement of the power factor .
Calculation of compensation power for a better active power factor
The required compensation power Qc to raise the power factor is calculated with the formula Qc = P * (tan φ₁ – tan φ₂). Example: To improve the power factor of a system with 100kW active power from a cos φ of 0.7 to 0.95, a compensation power of approximately 53 kVAr is required. An accurate calculation is essential for the effective improvement of the active power factor.
Den power factor in drives, PV systems, and inverters.
Motors: Efficiency starts with the active power factor.
Motors, especially older models (e.g., a 15kW motor with a cos φ of 0.75), are often a major cause of a low power factor in the industrial environment. Modern IE4/IE5 motors, such as those offered by ATEK, already have better active power factor values by default or enable optimization of the active power factor through the use of frequency converters.IE5 motors are a good example here of an improved power factor.
PV systems and the grid requirements for the active power factor
In photovoltaic systems, the power factor (cos φ) plays an important role in grid stability. Modern inverters can specifically provide or absorb reactive power, allowing the power factor to be influenced at the grid connection point (e.g., adjustable to cos φ 0.9 inductively or capacitively). The ability to provide reactive power to regulate the active power factor is now standard. This is also relevant for solar drives, whose inverters influence the power factor .
Inverters and Power Factor Correction (PFC) for an optimal active power factor
Many modern inverters and electronic consumers have integrated Power Factor Correction (PFC). These circuits ensure that the power drawn from the grid has a power factor of nearly 1 (cos φ ≈ 1). This minimizes the grid load due to harmonics and reactive power. PFC thus significantly contributes to grid quality and the improvement of the overall active power factor. This also optimizes the motor current consumption in terms of the power factor.
Difference between active power factor and efficiency
It is important not to confuse the power factor (cos φ), the ratio of apparent power to active power, with the efficiency (η), the ratio of usable energy output to energy input. For example, a light bulb has a power factor of nearly 1, but a very poor efficiency of about 5%. Both metrics, active power factor and efficiency, describe different aspects of energy efficiency.
Optimizing the power factor increases the overall efficiency of systems and reduces energy costs. The difference to efficiency must always be taken into account. ATEK Drive Solutions GmbH is happy to advise you on tailored solutions for improving your power factor.
In summary, a comprehensive understanding and active optimization of the power factor are essential for the efficient and cost-saving operation of industrial plants. By analyzing the causes of a low cos φ and strategically implementing compensation measures, the power factor can be significantly improved. This leads not only to lower energy costs but also to a longer lifespan of the equipment and a more stable energy supply. Considering the power factor is thus an important pillar for sustainable management and the competitiveness of companies. Modern drive technology and intelligent control systems offer various possibilities to effectively manage the power factor effektiv zu managen.
