Energy Meter Testing:
On-Site vs. Laboratory

Energy meters are an essential part of the energy management system. They are used to measure the amount of energy consumed by residential, commercial, and industrial users. To ensure that the energy meter is accurate, it is important to conduct regular testing. The testing can be conducted either on-site or at a laboratory. What are the advantages and disadvantages of both methods?

On-Site Testing

On-site testing involves testing the energy meter while it is installed in the building. This method has several advantages:

On Site Test With Calibrator Rs30 (credit Clou)
On Site Test With Calibrator RS350 (credit CLOU)

Convenience

On-site testing is more convenient than laboratory testing, as it does not require the removal of the energy meter from the existing installation. This means that the testing can be conducted without disrupting the power supply.

Accuracy on actual load

On-site testing provides a more accurate representation of the energy meter’s performance under its operating conditions. This is because the energy meter is tested in the actual environment in which it is installed.

Cost

On-site testing is generally less expensive than laboratory testing, as it does not require the exchange and transportation of the energy meter to a laboratory.

Capturing of external effects

Wrong external wiring, instrument transformer ratios and burdens can only be checked on-site. The same is valid for obvious tamper cases and broken seals.

On-site testing also has some disadvantages:

On-site testing may be limited by the availability of testing equipment and the technical expertise of the tester. It is important to ensure that the testing is conducted by a qualified and trained professional.
A disconnection of the customer for testing with an external voltage/current source is rarely possible. So, other loads or different power factors can’t be checked without allowance of the end-user.
On-site testing may be time-consuming, as it requires the tester to travel to the location of the energy meter. Additionally, the testing process may take longer as the tester has to work around the building’s schedule by appointment.

Laboratory Testing

Laboratory testing involves removing the energy meter from the building and transporting it to a laboratory for testing. This method has several advantages:

CLOU DC Meter Test Bench CL6350C
Example image: CLOU DC Meter Test Bench CL6350C

Control

Laboratory testing provides more control over the testing environment. This means that environmental conditions can be carefully controlled, and higher accurate measurement equipment can be used.

Accuracy

Laboratory testing provides a more accurate representation of the energy meter’s performance, as the testing is conducted in a controlled environment with selectable load-points, power-factors and harmonics injection. Also, it’s much easier to perform simple no-load-, starting- and register tests.

Efficiency

Laboratory testing itself is generally more efficient than on-site testing, as the testing process over multiple test steps can be completed more quickly and efficiently.

Laboratory testing also has some disadvantages:

Laboratory testing is more inconvenient than on-site testing, as it requires the removal of the energy meter from the building. This can result in disruptions to the energy supply and may require additional planning and coordination. Laboratory testing is generally more expensive than on-site testing, as it requires the transportation of the energy meter to a laboratory and may require additional fees for testing equipment and expertise.

Takeaway

The decision to conduct on-site or laboratory testing depends on various factors, such as the type of energy meter, the purpose of testing, and the resources available.
On-site testing is generally more convenient and less expensive, but it may be limited by the availability of testing equipment and the technical expertise of the tester. Laboratory testing provides more control over the testing environment and more accurate results over the full range, but it is more expensive and less convenient.
Ultimately, the decision to conduct on-site or laboratory testing should be based on a careful assessment of the specific needs and requirements of the situation.

Our on-site testing equipment provides the convenience of testing the energy meter without disrupting the energy supply, while our laboratory equipment provides precise measurements in a controlled environment with predefined test plans.
Contact us today to learn more and improve your meter test efficiency.

Editor's note: This article was originally published in May 2023 and has been updated for comprehensiveness.

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