Metering systems
New Metering System for the 4th Metering Train at U-3020 Aghia Triada
A new metering system for the 4th metering train at the U-3020 Aghia Triada station, for accurate gas flow measurement across the full operating range.
At the U-3020 Aghia Triada station, SEMAC installed a new metering system for the 4th metering train on behalf of T.C.B. S.A., for the end client DESFA. The project ran from April 2024 to November 2025.
The train measures gas flow with a Class 1 fiscal ultrasonic meter (USM), with pressure and temperature transmitters downstream of the meter and a flow computer. The flow computer takes the gas composition from the existing gas chromatographs and calculates instantaneous and integrated mass, volume and energy flow rates.
All equipment is CE-marked and meets ISO 17089-1 and AGA Report No. 9, with a total system error within ±1.0% over the full operating range. The photos show the new metering train in the workshop, with its transmitters, gauges and cabling.
Scope of work
Metering system
One ultrasonic meter (USM) with metering instruments and a flow computer One pressure transmitter and one temperature transmitter downstream of the flow meter Integration with the existing gas chromatographs for precise gas composition data
Performance and compliance
All equipment CE-marked and meeting the ISO 17089-1 and AGA Report No. 9 performance specifications Class 1 fiscal USMs: system uncertainty (mass flow) below ±1.0% and total USM uncertainty below ±0.5% Turndown ratio of at least 1:100, with high precision and repeatability below 0.05% Calibration deviation within ±0.3% from Qt to Qmax of the USM Total metering system error within ±1.0% at a 95% confidence level over the full operating range
Flow computer and data integration
Calculation of instantaneous and integrated mass, volume and energy flow rates Flow equations customised for the metering system, using gas composition data from the existing gas chromatographs
Interfacing and collaboration
Seamless interfacing between the new metering system and the existing systems Close collaboration with all suppliers and project stakeholders, for smooth integration and timely delivery
Photos and videos
4 photos
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