Oil immersed transformer Hot-Spot Temperature (HST) models based on IEEE and IEC loading guides
Abstract This article introduces two models based on the IEEE [1] and IEC [2] loading guides to compute the HST of a transformer winding. The models are solved numerically using arbitrary load and top oil temperature profiles. The results are then compared to highlight relative characteristics of the models. Introduction The Transformer Loss of Life […]
Read MoreTechnical note – MIRO Automatic FTP Uploads
This guide introduces how to setup an FTP system with automatic data uploads for the MIRO Power Quality Logger and Analyser. Introduction Purpose The FTP upload option provides automatic data collection without needing an application which periodically polls data to manage it. This has numerous advantages: Unsolicited reporting instead of polling allows for the device […]
Read MoreOver The Air Upgrade – Sierra Wireless HL7650 Modem
Updating the Firmware of the Miro’s Wireless 3G/4G HL7650 Modem Remotely, via the Sierra Wireless AirVantage Platform This guide illustrates how to update the firmware of the Miro instrument’s Sierra Wireless HL7650 modem remotely via the AirVantage platform, for the Miro instrument to be able to operate over Telstra’s upgraded 4G LTE network. The AirVantage […]
Read MoreAn Introduction to Transformer Harmonic Current Derating Metrics
Abstract Transformer harmonic current derating metrics; Harmonic Loss Factor, K-Factor, and Factor K are introduced, and used to calculate derating factors for dry and oil-filled type transformers. Introduction The introduction of Switched Mode Power Supplies (SMPS) in office equipment and LED lighting, Variable Frequency/Speed Drives (VF/SDs) to operate induction motors, and inverters that change DC, […]
Read MoreConfiguring the MIRO for cellular communications
This guide illustrates how to configure a MIRO Power Quality Logger and Analyser for cellular communications. Installing the SIM Step 1 : Unplug the MIRO from the all power sources (including the communications cable). The MIRO has a backup battery and will power down in five minutes if it was powered with a single phase […]
Read MoreIntroduction to Transformer Loss of Life – based on models from IEC and IEEE loading guides
Abstract This work introduces the concepts of Hot-Spot Temperature (HST) and transformer ageing due to temperature and how the HST affects transformer life expectancy. The relative ageing rate of two models are compared for various scenarios and the Transformer Loss of Life (LoL) is estimated for two HST profiles. Introduction LoL is the term used […]
Read MoreMirrin Firmware Release Notes
Mirrin firmware v1.20 (Updated 2022-08-01) Amended watchdog timer to cater to start up time of various modules. Ambient and surface temperature measurements interval now set to 2 seconds. Current sensor model F-6000 now supported
Read MoreCitrus Release Note
Citrus v1.3.0.22 (Updated 2023-03-15)v1.3.0.22 Citrus Release Notes Graphing of transformer loss of life parameters Transformer loss of life calculations can be based on either IEC or IEEE versions Transformer loss of life parameters available in DNP3 configuration form Transformer loss of life analysis tool, including features to analyse different scenarios Bulk export of Transformer loss […]
Read MoreMiro Firmware Release Notes
Miro firmware v3.17 (Updated 2023-03-15) Transformer Loss of life added LCD: Added degree symbol for temperatures Firmware default NTP sync interval adjusted to match the software default Calculation and logging of the positive, negative and zero sequence components for voltage and current Fix potential crash when MQTT/Sparkplug and DNP3-Comms are enabled at the same time […]
Read MoreCitrus Release Note
Citrus v1.2.8.5 ( Updated 2021-03-05)Miro: Four Quadrant Power. Allows users to quickly determine real and reactive power flow direction (Import, Export) in real time. NEC 220.87 Connected Load Survey Report. Quick way to confirm if additional load can be added to an installation, and if it conforms to NEC 220.87 regulations. Support ‘percentage of fundamental’ […]
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