Electrical Power Quality Measurement & Monitoring
Question that often become challenges in audit and assessments of electrical power quality activities is: Where are the power quality parameter measurement location or points or place, when and how long the duration of power quality monitoring carried out? This is especially when define power quality measurement time frame for an electrical system troubleshooting. We will discuss briefly the location and duration of monitoring or observation electrical power qualitiy. The article will mostly adopt IEEE 1159 Recommended Practice for Monitoring Electric Power Quality. —Omazaki Consultant is a consultant that provides electrical power quality measurement, inspection, verification, and monitoring services for both commercial and industrial facilities. If you are looking for a power quality measurement and observation consultant, please contact us by sending an email to firstname.lastname@example.org or by filling in the form in contact.
Define the Measurement Objective
Before measuring and monitoring power qualities, it first to define the objectives. Power quality monitoring is necessary to characterize electromagnetic phenomena at a particular location on an electric power circuit.
The objectives of monitoring will determine the choice of monitoring equipment, method of collecting data, triggering thresholds needed, data analysis technique to employ, and the overall level of effort required of the project. The objective may be as simple as verifying steady-state voltage regulation at a service entrance or may be as complex as analyzing the harmonic current flows within a distribution network.
The procedure for defining monitoring objectives differs by the type of study. For example, when diagnostic monitoring is used to solve shutdown problems or troubleshooting with sensitive equipment, the objective may be to capture out-of-tolerance events of certain types.
Need for Power Quality Monitoring
There are several important reasons to monitor, inspection and verification power quality. The primary reason is economic, particularly if critical process loads are being adversely affected by electromagnetic phenomena. Effects on equipment and process operations can include mis-operation, damage, process disruption, and other such anomalies. Such disruptions are costly since a profit-based operation is interrupted unexpectedly and must be restored to continue production.
Measurement & Monitoring Location
It is important to consider the entire electrical environment prior to connecting a monitoring device. This can best be done by drawing or obtaining a single-line diagram of the electrical circuit being monitored. Decision on power quality measurement and monitoring location is based the objectives. Based on IEEE 1159, the initial location to install a power quality monitor will be dependent upon the objective of the survey.
- If the power quality inspection and monitoring objective is to diagnose an equipment performance problem, the monitor should be placed as close to the load as possible
- If there is power conditioning or filtering, monitor should be installed between the power conditioning equipment and the equipment
- If the objective of power quality verification is to investigate the overall quality of a facility, the monitor should be placed on the secondary of the main service entrance transformer.
Below are the problems and recommended monitoring location.
Monitoring Duration Based on IEEE 1159
The monitoring period is a direct function of the monitoring objective. Usually the monitoring period attempts to capture a complete power period, i.e., an interval in which the power usage pattern begins to repeat itself. However, for seasonal problems, the monitoring period might be for months. An industrial plant, for example, may repeat its power usage pattern each day or each shift.
The most important aspects are to understand what time periods the data represent and not to assume that no changes in facility operation have occurred.
Baseline Power Monitoring
Baseline monitoring is primarily used prior to installing equipment to verify power specification compliance. The recommended monitoring period is defined as a complete working cycle (power period).
Locating a power problem that causes a specific equipment/load malfunction can take days to weeks. This type of activity is intended to find the specific power disturbance that creates the problem and document its repeatability (similar to documenting a software bug). Once the problem is found, a corrective action is implemented. After implementation, power monitoring is conducted to check the effectiveness of the solution and to verify that no new types of problems have been created.
Power Study Monitoring
This type of monitoring or observation power quality is of key importance in understanding how the overall power quality picture is changing as a result of major changes in the environment. Power studies are conducted for long periods of time, usually a few years, at multiple locations.
Monitoring Duration Based on SPLN D5.004-1
Indonesia State Electricity Company Standard SPLN D5.005-1:2012SPLN D5.005-1:2012 about Power Quality – Regulation of Harmonics, Flicker and Voltage Unbalance states that the point or location of harmonic measurements at the customer connection point is as in the picture below
Harmonic measurements are carried out at certain time periods to obtain the characteristics of harmonic levels. Measurements over this time period are carried out to assess customer installation needs and in the context of new connections and power changes. Harmonics measurements are carried out under the following conditions:
- Carried out for a minimum period of 7 (seven) days under conditions where the electrical load installation operates with normal loads and cycles
- Minimum 95% of measurement data must meet the required limits
Contact Omazaki Consultant if you are looking for consultant who provides electrical power quality parameter measurement, inspection, verification, observation and monitoring services to help you auditing, assessment and problem troubleshooting existing system.
- Power Quality Audit & Assessment
- Power System Transient Stability Study
- Voltage Drop Study & Analysis
- Voltage Imbalance (Unbalance) Study
- Harmonic Study & Analysis
- Electronic Power Quality & Grounding
- Power Quality Monitoring
- Electrical Energy Audit