Which electricity meter is the right one?
Electricity Meter Lexicon – Lesson 1: Overview of Meter Types for Energy Management
In our blog series „Electricity Meter Lexicon“ we would like to share our experiences with the most diverse measuring systems.
In this first lesson we provide an overview and help with the selection of meter types in industrial companies.
Background: Energy meters are used to measure electrical quantities. In most cases, it is a matter of recording work performed or (active) power consumed. In individual cases the measurement of further values can be important, e.g. to check the power quality. For some models, the main voltage is recorded, for more powerful measuring devices also harmonics, total harmonic distortion, flicker and others. In practice, a distinction must be made between readable and non-readable meters and between meter readings and instantaneous values.
Power Quality Analyzers (>800€)
- Installation location: transformer underside in the NSHVT or for special loads
- Data: Meter readings, powers, voltages, harmonics, THD, flicker, etc.
- Communication interface: Modbus TCP
- Examples: Siemens Sentron PAC 4200; Janitza UMG 508/512; Janitza UMG 96RM-E
Normal multifunction measuring instruments (250-500€)
- Installation location: transformer underside in the NSHVT, outlets of systems in the NSHVT
- Data: Meter readings, outputs, voltages, sometimes harmonics, THD communication
- Interface: Modbus TCP
- Examples: Siemens Sentron PAC 3200, Janitza UMG 96RM-EL, KBR multimess, Celsa TNM 96, Somec Diris
Simple meters (150-300€)
- Installation location: Outlets from systems in the NSHVT, sub-distributors or control cabinet
- Data: Meter readings
- Communication interface: M-Bus, partly proprietary
- Examples: ABB, Finder, Berg, EMH, etc.
Analog meters (~100€)
- Installation location: transformers in the NSHV, large systems in the NSHV in older systems
- Communication interface: none
- Data: none
The most important thing: Choosing the right energy meter
Our experience and recommendations may help you in your decision.
From our support in the creation of measurement concepts, our installation activities and the good exchange with numerous customers from different trades, we can make the following recommendations:
- Tip 1: Avoid analogue electricity meters.
- Tip 2: Choose multifunction meters with communication interface (e.g. Modbus TCP) if you want to be future-proof. In general, they offer the cheapest and most comprehensive solution. All relevant data is collected and instantaneous values can be read out. The systems are equipped with extensive interfaces and thus offer great compatibility with other data acquisition systems.
- Tip 3: Power Quality Analyzers, on the other hand, are quite expensive and simply not necessary in most cases. They are only used where sensitive devices are connected that are allergic to flicker (short-term voltage fluctuations), for example, or where harmonics of high harmonics have to be detected.
- Tip 4: Make sure that the meter supports a standardized communication protocol and is not proprietary, i.e. not compatible with other manufacturers. We recommend Modbus TCP, as it greatly facilitates the introduction of an energy management system.
In the next lesson: The right measurement concept.