THE IMPORTANCE OF MEASURING ENERGY QUALITY IN THE ELECTRIC

THE IMPORTANCE OF MEASURING ENERGY QUALITY IN THE ELECTRIC DISTRIBUTION NETWORK(electrician)

The Quality of Energy is defined as any event manifested in deviations of voltage, current, or frequency that result in failures or bad operation of the end-use equipment. This means, that the quality of the energy or the quality of the electrical supply,more than defined by limits established in standards, is defined by the requirement that my electrical / electronic equipment have to operate properly, without suffering damages or unexpected stoppages.

Maybe there is no other individual segment of a company as important as the power, because without the power the complete production system stops working. Despite this, the issue of measurement, control, analysis and management of energy quality is seen by many as difficult and complex engineering work.

Despite the fact that many efforts have been made by electrical companies, some consumers require a level of energy quality higher than the level provided by modern electricity grids. This implies that it is necessary for these consumers to take measures to reach higher levels of Energy Quality.

Nowadays, it is of great importance for the engineers and technicians who solve critical equipment maintenance problems, and for the contractors who maintain the electrical distribution systems they install; the measurement and analysis of the quality of energy, has become a basic necessity, as well as using the hook ammeter.

It is time to answer the following questions:

What is my cost for electricity quality problems per month or year?
What are the areas critical to the quality of the electricity supply?
What am I doing to prevent and reduce costs due to problems in the quality of supply?

PORTABLE AND PERMANENT POWER QUALITY ANALYZERS
When an electrical distribution system does not fulfill its purpose, it is time to investigate the problem, find the cause and initiate corrective action. The purpose of the electrical distribution system is to allow the proper functioning of the installed loads. When a load does not work properly, the quality of the electrical power in the distribution system should be suspected as a possible cause.

Traditionally, most of the measurements of energy quality have consisted in direct search for faults and troubleshooting. Machinery breaks down, lights flicker, robots stop, electronic devices stop working. However, the analysis of the quality of energy must be considered, and is of great value, also before a specific action or reconstruction of the network and after performing it as a follow-up and verification measure after the changes. In this way you can make sure that the changes have had the desired effect, and / or you can also analyze what impact they have had.

The quality analyzers allow you to observe the readings in real time and also to record data for analysis. There are permanent energy quality analyzers that are installed in different points of the electrical distribution system, and are considered as a preventive solution; and there are also portable power quality analyzers especially used for the reactive solution of problems.(emergency lighting)

With portable analyzers, one can often reach near the source of the disturbance and subsequently correct any fault. The realization of an analysis of energy quality with a portable analyzer starts with planning. The objective of the analysis and detailed information of the electricity distribution network must be clear. The start of monitoring is usually done as close as possible to the critical point of analysis. It should always be considered that the problems of energy quality can come from the electric company, but they can also be generated within the installation itself. In fact, there are studies that imply that most problems are generated internally.

Currently, many industries and companies work proactively with continuous monitoring of energy quality to detect sources of disturbances and failure conditions in the network, before the consequences are serious and very costly. These energy quality analyzers have great analytical capacity, so they give great opportunities to work with statistics and trends in a preventive and predictive manner.

The quality analyzers permanent energy have important benefits:

They are an "early warning" system, this allows problems to be corrected before they become large-scale failures with high downtime and costly production losses.
Attribute quickly problems in the quality of energy, which allows finding a timely and rapid solution to the problem,
Identify if the problem of energy quality is caused by the power supply of the electric company or by problems within your electrical installation?
Other no less important benefits of the energy quality analyzers are given in the energy saving:

Know the distribution of load consumption within your facility. Obtain daily, weekly and monthly trends of energy consumption.
Projection and growth, allows you to determine if you can operate more loads without having to increase the capacity of your electrical system.
Detect and avoid equipment failure by measuring and analyzing energy consumption over time . Also useful for substitution valuation of high consumption technologies.
Demand control: manage energy consumption during periods of high cost.

IMPORTANT CONCEPTS AND STANDARDS

Whether real-time values ??are observed on the portable analyzer's screen, or data downloaded from the laptop is analyzed or data is analyzed online, it is necessary to understand the parameters of energy quality and its characteristics. The energy quality standards IEEE 1159, EN50160, IEEE 1100 are excellent resources to begin to understand the terminology of energy quality, problems analysis and corrective actions.(commercial)

Following is a brief detail of the most common problems of energy quality:

Voltage drops (SAG / DIP). A decrease in the normal voltage level between 10 and 90% of the nominal voltage rms at the power frequency, for durations from 0.5 cycle to 1 minute.

Very short interruptions : Total interruption of the power supply for the duration of a few milliseconds to one or two seconds.

Long interruptions: Complete interruption of the power supply for a duration longer than 1 to 2 seconds

Overvoltage Transients: Very fast variation of the voltage value for durations of several microseconds to a few milliseconds. These variations can reach thousands of volts, even at low voltage.

Voltage increases (SWELL): momentary increase of the voltage, at the power frequency, outside the normal tolerances, with duration of more than one cycle and typically less than a few seconds.

Harmonic distortion: Voltage or current waveforms assume a non-sinusoidal shape. The waveform corresponds to the sum of different sine waves of different magnitude and phase, with frequencies that are multiples of the frequency of the power system.

Voltage unbalance: A voltage variation in a three-phase system in which the three voltage magnitudes or the phase angle differences between them are not equal.

FINAL CONSIDERATIONS FOR THE MEASUREMENT OF PQ ENERGY QUALITY
The measuring instruments for the quality of the energy cover a series of different measurement parameters and for the measurement to be reliable there must be a clear definition of how the measuring instrument measures and calculates these. While the basic variables such as RMS voltage and current values ??are well defined, some power quality variables are not. This has led to a situation in which different instruments could show different results. For this reason the measurement standard was created 
The standard, issued by the International Electrotechnical Commission,