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Energy Management is to ensure reliability, safety, and energy efficiency of power supply. Inadequate maintenance of energy-using systems is a major cause of ineffective energy consumption in commercial and industrial sectors. This subject could cover mainly two aspects in which Power Audit and Energy Audit are the starting point of an energy management plan.

Maintaining Power Quality
When it comes to Power Audit, the cost of sags, transients, outages, and harmonics could be very expensive, not to mention disruptive, as data is lost, equipment damaged and procedures interrupted. Power quality is especially critical for the types of sensitive applications found in data centers and healthcare facilities. These operations require near 100% uptime, and a higher level of power quality then traditionally used by electrical equipment.
Power anomalies come in many forms and go by many names. Briefly, these disturbances are broken down into six categories :-

• Transients - These are sub-cycle disturbances with a very fast voltage change. They typically have frequencies of tens to hundreds of kilohertz, with some even into megahertz. The voltage excursions range from hundreds to thousands of volts. Transients are also called spikes, impulses, and surges.

• Momentary Interruptions - refers to a loss of voltage ranging from less than a cycle to several cycles. Though they do not last long enough to be called outages, in reality that's what they are.

• Voltage Sags And Swells - These are variations in the RMS voltage from about one half cycle to several seconds. They are characterized by changes in the RMS voltage value. Sags refer to a reduction in the voltage, while swells deal with a voltage increase.

• Undervoltage Or Overvoltage - A sag or swell last for longer than several seconds and these disturbances may last indefinitely.

• Harmonic Distortion. If the voltage or current wave-shape is not sinusoidal, it is considered distorted. Since our entire power system was developed with sine waves in mind, harmonic distortion challenges many of our basic concepts about how to transmit, distribute, use and maintain electric power.

• Electrical Noise, sometimes called electromagnetic interference, or EMI. EMI consists of high frequency, low voltage signals coupled onto the power lines. Frequencies may vary from the kilohertz to the megahertz range, and magnitudes may be up to 10 or 20 volts.
  　

With the power analyzer, the abnormal power disturbances during a period of time are recorded for power quality analysis. The objective of a power quality audit is a method to find a solution to the problems. This is accomplished by checking wiring and grounding, which causes about 80% of most commercial and industrial problems, and checking the quality of both the internal and external voltage. This data is then analyzed to determine an appropriate recommendation to existing electric utilities.

Achieving Energy Saving
The term “Energy Audit” refers to the procedure of collecting and analyzing available energy-related data in order to establish the most accurate breakdown of energy consumption for a particular building operation, and to identify energy-saving opportunities within the building facilities. The energy audit would give a positive orientation to the energy cost reduction, preventive maintenance and quality control programmes which are vital for production and utility activities.
　

Energy audit broadly covers the following questions:

i. How much energy are we consuming?
ii. Where is the energy consumed?
iii. How efficiently is the energy consumed?
iv. Can there be improvements in energy use?
　

A detailed audit report will contain comprehensive measurements at the building facilities and units selected. Each audit will consist of the following tasks:-

• Elaboration and discussion of audit methology.

• Selection of plants or items to be audited.

• Collection of more detailed energy and production data, if available.

• Comprehensive measurements at selected plants items.

• Data analysis and calculations

• Elaboration of energy and material balance for the audited plant items.

• Investigation of existing energy management structures.

• Recommendation of feasible energy efficiency measures.

• Financial analysis of recommended measures, including cost benefit calculation.

• Ranking of measures and elaboration of an energy saving action plant\

• Reporting

The installation of accurate monitoring instrument is very important for implementing a good energy management scheme. Attention is drawn to the following areas :

1. The whole plant, including every equipment and every major equipment, should be under the control of the monitoring system

2. Monitoring system should operate automatically (recording and alarming) and computerized (statistics and analysis).
   　

We are in a position with well experience to supply accurate instrument for monitoring and necessary controls. By virtue of our practical experience, we are also honorable to be cooperating with VTC for educational projects on the subject of Energy Management with their theoretical approaches to data analysis.