Overcoming the limitations of Power Quality Field Investigation with OTELLO

Power transformers require consistent testing and maintenance to assess their condition and to uncover the issues that threaten the network. Maintenance engineers are a critical link in building power grid resilience and stability. A range of tools and technologies exist to assist engineers in their quest, with most investigations requiring a combination of devices to test the different parameters.

Introducing OTELLO, the revolutionary Class-A multifunction edge computer that lets you see and manage the grid remotely.

OTELLO is not like any Power Quality Investigation (PQI) device on the market. Each device has an onboard edge computer that allows data processing on the device, and a built-in GPS clock that is time synchronised to within ±100ns from absolute time. This local processing and real time synchronicity allows every OTELLO device to communicate in perfect harmony with every other VectoIII® device in the investigation, even hundreds of miles away.

Most high-speed Power Quality Investigation (PQI) devices only support a variable sampling rate!

This means that the sampling rates are not fixed – they vary with the network frequency and are therefore inaccurate to use directly in analysis software.

OTELLO Vecto III has a fixed sampling rate of 500kHz.

• All waveform data are down sampled to obtain a fixed 50kHz data stream (Each 50kHz sample is therefore constructed from 10 samples obtained from the 500kHz stream)
• All parameters are calculated from these two fixed rate data streams.

All recorded data is time-stamped to within ±100ns from absolute time.

This makes it possible to import waveforms, recorded on two or more devices, into a spreadsheet and directly compare the waveforms without any modification.

A fleet of OTELLO VectoIII® devices, connected to the OTELLO OspreyPRO® SaaS platform, are effectively one large, virtual, clock-synchronised measurement instrument.

This high level of time synchronisation allows you to directly analyse data recorded from different devices over the same time period. No human intervention is required to then manually overlay and synchronise the data sets.

This keeps the accuracy and data integrity at an exceptionally high level.

Accurate & Comprehensive

The high sampling rate and high level of time synchronisation in combination results in pinpoint accurate amplitude and phase information.

The OTELLO VectoIII® records a comprehensive set of RMS, phasor, harmonic & synchrophasor data, covering over 9,000 individual parameters. The device records the following time-synchronised streams simultaneously:

• 50kHz
• ½ Cycle RMS
• 200ms
• N * 200ms
• 3sec
• N * 3sec
• N* 1min
• 10min
• 2h
• 24h

Power Quality Events:

OTELLO VectoIII® can record all the power quality event parameters available in the various international power quality standards.

Diagnostic data included per event as follows:

• Pre- and -post 50kHz fixed sampling rate waveform data (up to 1-min pre, unlimited post)
• ½ Cycle RMS and phasor data

Various Power Parameters

All RMS and fundamental Power parameters are available. As NETT, Imported and Exported.

Harmonics

The OTELLO VectoIII® implements 3-sec time constant filters, required on individual harmonics and is therefore certified as a Class-I harmonic emission analysis device.

The device records:

• Prevailing phasor amplitude and angles that are currently under discussion within Cigre.
• Higher harmonic bands from 2kHz up to 25kHz as described in the latest harmonic standard.
• Both harmonic amplitude and phase performance data – it is one of the only devices available on the market with this ability.

Linearisation of Voltage Transformers (VT’s) and Current Transformers (CT’s)

VT & CT linearisation is a unique OTELLO VectoIII® feature.

The device has the built-in ability to compensate for harmonic phase and amplitude errors that occur in commercial VT’s and CT’s, provided the performance of VTs and CTs can be characterised in the lab. This characterisation can then be applied and compensated for in the field.

Remote Device Access

Each OTELLO VectoIII® has a built-in cellular modem. Operators have full access to the device through this broadband remote link. Each device also hosts a built-in web interface, enabling it to be locally configured. Real-time data is displayed without requiring any special external software.

The web interface is also accessible via the built-in WiFi device. Simply link directly to the WiFi access node from any tablet, mobile phone or laptop that has a WiFi capability.

It is also possible to reverse or swap current or voltage channel inputs remotely in the event that phased voltage or current inputs were incorrectly wired during installation.

OTELLO Cloud-based Data Hosting, Analysis & Visualisation & Alarming

OTELLO offers a cloud-based big-data hosting, analysis & visualisation solution for field installed devices. Communication is via a cellular link or an Internet connection provided by the local network.

Data is accessible in real-time. The system also supports an alarming mechanism via email or mobile push notifications to immediately notify any individual that subscribed to the alarm.

The OTELLO system is feature-rich and offers a bespoke range of data analysis reports, dashboards, graphs and tables. Data, graphs and reports can be exported in vector graphic format – simplifying the process of creating custom reports.

Certified by NMI

Certified as an IEC61000-4-30 Ed3.0 Class-A device using the IEC62586-2 test protocol

Custom data export for Digsilent

Should you require a custom data export function, that will pre-prepare the exported data into the format required by Digsilent, speak to us.

Talk to us about you Power Quality Investigation Requirements