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What is Electrical Energy?
All the devices connected to the electrical grid consume electricity. Nevertheless, all the equipments that have magnetic circuit and operate on alternating current (motors, transformers, reactances, lamps, etc.) in normal operation produce electricity that doesn’t produce any work, commonly called reactive power.
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What is Active Power and Reactive Power?
Active Power is the one that actually produces work. Examples: lighting a lamp or a motor running.
Reactive Power is the one that doesn’t produce work, which is created by inductive circuits, such as motor coils, transformers, reactances and other equipment. The production of reactive power must have the smallest possible value. An excess of reactive power requires, for instance: larger section conductors and higher capacity transformers, in addition to causing losses by heating and voltage drops, resulting in losses.
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Power Factor
The power factor is classified as inductive or capacitive.
The inductive power factor means that the electrical installation is producing inductive reactive power to the network. A feature of motors, transformers, reactances, lamps, etc.
The capacitive power factor means that the electrical installation is supplying capacitive reactive power to the network. These are features of the capacitors, which are usually installed to provide capacitive reactive power, nullifying the effect of the inductive reactive power, which inductive equipments produce. The power factor becomes capacitive when the capacitors are in excess. This occurs mainly when the inductive electrical equipments are turned off and the capacitors remain on or oversized.
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Benefits of power factor correction: - Decrease in voltage variations
- Reduced heating in the conductors
- Reduce energy losses
- Better use of the transformers capacity
- Increased equipment lifetime
- Rational use of the consumed energy
- Eradication of the consumption of surplus reactive power, which is charged in the energy bill
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Possible solutions:
By reducing the operating hours of motors under low load, or unloaded, by using high efficiency motors and by applying Electronic Speed Variators.
Through the compensation of reactive power using capacitor batteries associated with online monitoring systems, through energy management systems or by email or SMS alerts.
Aware of the importance of costs stemming from the production of inductive and capacitive reactive power in the facilities, especially in industrial ones, it is essential to supervise the proper operation of the Power Factor Correction systems.
Aware of this new reality, EXSEPI developed an Energy Management System called SGE-Reactive.
Overall the system consists on the analysis of energy quality by communicating with the varimetric relay and, whenever an anomaly occurs, it sends notifications by email or SMS to those in charge of the facilities.
The cost of active power is subject to a penalty for the production of inductive and capacitive reactive power, according to the Regulation 7253/2010 of April 26.
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Reactive Power billing rules: - The metering and billing of reactive power focus on customers connected to VHV, HV, MV and SLV, in the areas of inductive reactive and capacitive reactive
- The inductive reactive is billed in peak and off-peak hours, in the component that exceeds by 30% (starting on January 2012) the active energy consumed in the same period
- The capacitive reactive is billed on the total energy injected into the network on the unloaded hours
- The price structure is staggered and progressive, resulting of the reference price product of the inductive reactive with multiplicative factors, and the capacitive reactive, whose factors are published annually by the regulator
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