The reliability and consistency of your electrical supply is one of the most important factors that need to be taken into consideration when it comes to the activities of both the industrial and the service based companies. Problems originating from poor Power Quality include interruptions, dips or harmonic pollution. Therefore the loads connected to a network, where such problems are prevelant, will fail, have a short lifetime and the efficiency of the system will decrease.
According to Leonardo Energy organization, the financial losses due to poor Power Quality amount to a total of €150 billion (Which equates to roughly R195 255 750 0000.00) annually in the EU-25. And its impact in the rest of the world is in the same order of magnitude.
COST OF POOR POWER QUALITY
The ideal state of a load would have a constant magnitude and frequency voltage waveform. However this is not possible in real installations (outages, non-zero impedance, etc. ). The consequences of poor Power Quality include:
- Unexpected power supply failures (breakers tripping, fuses blowing).
- Equipment failure or malfunctioning.
- Equipment overheating (transformers, motors, …) leading to a reduction in their lifetime.
- Damage to sensitive equipment (PC's, production line control systems, etc.).
- Electronic communication interferences.
- Increase of system losses.
- Need to oversize installations to cope with additional electrical stress with consequential increase of installation and running costs and associated higher carbon footprint.
- Penalties imposed by utilities because the site pollutes the supply network too much.
- Connection refusal of new sites because the site would pollute the supply network too much.
There are two main parameters that need to be considered when evaluating the quality of power being supplied:
- The continuity of power supply, understood as no interruptions in the electrical supply.
- The voltage quality, understood as the quality of the waveform (amplitude, frequency, variations, etc.).
There are many factors that affect the quality of electricity. Some of the most important ones are:
- Utility related factors (Management and functioning of the grid, maintenance etc.)
- Factors related to the end-user (Failures at the user facility, noise emitted on the network etc.)
- independent (environmental factors, weather phenomena, damages caused by third parties etc.)
MONITORING POWER QUALITY AND HARMONICS
Power Quality monitoring is already a service provided by the grid utilities to their core customers (Big industrial and commercial energy users). But, many studies have concluded that most of the problems happen within the customer's facility. This fact means that monitoring the Power Quality after the utility meter provides a range of benefits both for the utility and end-user. This is even more true in a scenario where many end-users are also energy producers.
Monitoring the Power Quality will allow for the detection of the sources/causes of the problems within the end-user's network. The solution would be either removing the source or making the installation immune to the the poor power quality. Both solutions usually cost far less than the potential damages that may result due to poor Power Quality.
Unfortunately, there are still a large number of end-users that do not invest in implementing Power Quality Monitoring and Management systems.
Many stakeholders are unaware of the potential threat that poor Power Quality can have on their facilities. This could be due to the lack of information but also the fact that most of the costs pertaining to poor Power Quality are hidden.
HOW ELECTREX CAN HELP YOU
The Electrex Power Quality Energy Analyser & Data Manager of the Kilo Power Quality product family, in addition to its ability to measure and manage power consumption, is designed to monitor the Power Quality of the supply to various points.handle
The Kilo Power Quality devices are used for:
- The recording of Power Quality related events.
- Preventive maintenance.
- Power Quality problem detection.
- Power Quality measurement campaigns for specific time periods defined by the user.
- Monitoring of the compliance with Power Quality standards or service standards
Power Quality (Class S - EN 61000-4-30): Events Log:
The Kilo D6 PQ detects and logs various types of events with a resolution of one cycle (With date / time * of each event, type of event, phase involved, duration, min / max value reached during the event and UNIPEDE classification) useful for monitoring the quality of energy (Functions related also to the EN 50160 and EN 61000-4-30 standards for the S class).
The parameters for defining abnormal events are programmable.
Event types:
- Voltage Dip
- Voltage Swell
- Over current (and its direction)
- Interruption
(*) Date/hour expressed in hours, minutes, seconds and milliseconds referring to the instruments' (local time). In the table are displayed also some functioning logs as the ones related with the start and configuration settings.
EVENT'S GRAPHIC DETAIL
The Kilo D6 PQ includes a functionality called "Event's graphic detail" that allows to record and display the trends of the beginning and end of events with a time frame (For both beginning and end) of a second (Programmable).
EVENTS TIMELINE AND THE UNIPEDE TABLE
The Kilo D6 PQ can display a timeline of the succession of events:
The unit also maintains a diagram of distribution of events based on the % of the considered parameter in relation to its reference value and duartion (This complies with the UNIPEDE (International Union of Producers and Distributors of Energy).
Example: In the last column of the table here below , the S1 denotes a Voltage Swell with a duration between 10 and 500 mS (refer to the UNIPEDE table above), while the X2 denotes a Voltage Dip lower than 5% of the nominal voltage value with a duration between the 10 and 200 mS.
MEASUREMENT CAMPAIGN
With the Kilo D6 PQ it is possible to configure the measurement campaign in order to log, in the built-in memory, the various parameters with a programmable sampling rate.
Example of a daily measurement campaign of the 3 phase voltages below:
With regards to the quality of the voltage, the Kilo PQ refers to the European standard EN 50160 which distinguishes the different disturbances in continuous phenomena and voltage events.
The continuous phenomena include:
- Frequency variations.
- Variations in the supply voltage.
- Voltage imbalance.
- Voltage harmonics.
The voltage events include:
- Interruptions of the supply voltage.
- Voltage dips.
- Super-elevations at industrial frequency and transient voltage.
ORIGIN OF DISTURBANCES
Noises are always present in electrical networks and are mainly produced by:
- Failure on the supply line of the user or on the other lines connected to it.
- Failures of internal networks of customers.
- Inrush currents of transformers and capacitors.
- Rapidly varying loads and peak currents of motors.
- Non-linear loads.
VOLTAGE QUALITY INDICATORS. WHAT TO MEASURE.
The monitoring voltage quality examines the following parameters:
- Amplitude and rapid/slow voltage changes.
- Voltage dips.
- Harmonics.
- Voltage imbalance.
When running a Power Quality monitoring program, it is important to consider that the network changes continuously. Traditional measuring devices are not suitable for monitoring non linear loads as the equipment used must measure in True RMS and must specify the range of a single Harmonic measured.
To get more information on these and other Electrex products, please feel free to contact us here.