Real Time Fault Level Monitor (RTFLM)

The first ever compact unit capable of measuring Peak and RMS Prospective Short-Circuit Current (Fault Level) in Real Time.

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What is Real-Time Fault Level Monitoring?

Fault level, also known as short circuit current, is a critical parameter for Distribution Network Operators (DNOs).

It represents the highest current that could flow in the event of a fault – a value that determines the specifications and safety ratings of vital network equipment.

Accurately measuring and managing fault levels is essential for protecting assets, ensuring the safety of on-site teams, and facilitating the connection of any new generation whether it’s renewable, inverter-based or synchronous generation.

Traditional fault level modelling approaches, while universally used, are acknowledged to be vulnerable to the quality of input data, as well as the actions of customers remote from the modelling process, and may not reflect the true, real-time conditions on the network. This is where Outram Research Ltd’s pioneering Fault Level Monitoring technology comes in – the algorithm behind the world’s first commercially available devices capable of directly measuring fault level.

These devices measure the prospective short circuit current either:

Passively by observing natural disturbances on the network – the Outram PM7000 Fault Level Monitor, the PM7000FLM; or
In real-time, in as little as 15-20 seconds, by creating its own small perturbations on the network – The Outram Real Time Fault Level Monitor, the RTFLM™.

Waveforms taken from RTFLM installation in Liverpool, UK, over a five-week period. The top waveforms are the voltage measurements taken from the VT. The middle waveform is peak ½ cycle FL, and the bottom waveform is Root Mean Squared (RMS) break FL.

Figure 4, Paper 303, REAL TIME FAULT LEVEL MONITORING TO INCREASE ELECTRICITY DISTRIBUTION NETWORK UTILISATION, CIRED Vienna Workshop 2024,Ralph Eyre-Walker(SP Energy Networks, UK), John Outram, Outram Research Ltd, UK, Adham Makki (UK Power Networks, UK)

Our Fault Level Monitoring Solutions

RTFLM™ – Real-Time Network Monitoring

The RTFLM represents the latest advancement in fault-level monitoring technology. It provides continuous, real-time measurement of Prospective Fault Level (Short Circuit Current) by actively measuring the dynamic source impedance and operating voltage of your network.

Key Features:

Rapid results, continually updating to new network configurations within 15 seconds using controlled network disturbances
Generates RMS Break Fault Level (50-100ms selectable), ½ Cycle Peak Fault Level measurements which includes both upstream and downstream short circuit current contribution
Results generated for a 3 phase bolted fault condition
Continuous monitoring capability
Suitable for voltages up to 33kV with testing in progress for 132kV
Available in two variants:
- Full System (up to 10 load inductors) for higher voltage applications
- Traveller System (2 load inductors) for lower voltage applications, relocatable to additional locations
Proven accuracy through independent testing:
- Peak fault level accuracy within 2.5% at 33kV, 2.0% at 11kV
- RMS break (90ms) fault level accuracy within 2.4% at 33kV, 0.8% at 11kV
- Response time typically under 15 seconds

PM7000FLM – Passive Monitoring Solution

The completely passive, portable PM7000FLM generates ½ cycle peak and RMS Break upstream measurements with separate ½ cycle downstream contribution measurements on radial or radialised sections of the network using naturally occurring disturbances as small as 0.15% voltage variation. It can be deployed at voltages up to 33kV. Results have also been successfully obtained at 132kV but this is dependent on substantial disturbances being present such as generated by high voltage load switching, making it a versatile solution for NOs with various network topologies.

Validation and Real-World Impact

Both systems use a unique processing methodology developed in collaboration with SP Energy Networks and UK Power Networks. Their effectiveness has been demonstrated through extensive testing and real-world applications:

Independent validation through full-scale tests on national grid-backed networks (Veiki Laboratories, Hungary)
Testing at the Power Networks Demonstration Centre, (Cumbernauld, UK) using Real Time Digital Simulation
Proven field results with major utilities

As demonstrated in a case study with SP Energy Networks in Chester, our fault level monitoring technology provided accurate, real-world measurements that were used to update computer-modelled values, leading to a more reliable assessment of available fault level capacity. This resulted in savings of over £250,000 by removing the immediate need for network upgrades. See Energati Article on our Fault Level Measurement development journey with case studies here.

Real Time Fault Level Measurements Available in SCADA

Integrated communications solution enable parameters such as Peak fault level, RMS fault level and confidence figures to be streamed over IEC 60870-5-104 to the control room SCADA system with typical diagnostic parameters recorded in, for example, Pi Historian.

Supplementary communications pathways through the same device support full session data transfer and device configuration, allowing adjustments to settings such as pulse length, pulse duration, measurement aggregation interval, alternative parameters measured, and more.

Network Management Benefits

Supporting the Net Zero Transition

Facilitates integration of renewable generation
Enables confident network capacity assessment
Supports distributed energy resource connections
Helps maximize existing infrastructure utilisation giving the option of active network management using Fault Level

Enhanced Safety and Asset Protection

Real-time visibility of fault level conditions
Improved protection of personnel and equipment
Early identification of potential risks
Validation of existing safety margins

Operational Efficiency

Continuous monitoring of network conditions
Rapid response to network changes
Reduced need for conservative estimates
Optimized asset utilization

RTFLM Technical Specifications

Measurement Voltage: 415V to 33kV
Power Input: 415V ±20% r.m.s. phase-phase
Response time to network changes: Typically for large network alterations <15 seconds. Small network changes measured in real time, dependent on pulse aggregation period.
Voltage Frequency: 45 – 64Hz
Power Consumption: 10VA (not pulsing), 25kVAR max
Data Communication: IEC60870-5-104, PMGateway app, Bluetooth (can be disabled), USB, MODBUS ASCII
Available Configurations:
- Full System (380 kg): For higher voltage applications
- Traveller System (120-140 kg): For lower voltage applications
Connection requirements: 3 VT input channels from target bus bar and 1 Phase-Phase Power input channel at 415V from a local Distribution or Auxiliary Transformer. There can be no intermediate interconnection between voltage and power connections.

System Requirements

Dedicated coupling transformer recommended
Suitable earthing and protection systems
Windows 7 or later for Pronto Software
Android or Windows compatible devices for PMScreen/PMGateway

Supporting Services

Comprehensive installation guidance
Technical support and training
Data analysis software
Integration with existing systems

For detailed technical specifications, installation requirements, or to discuss your specific needs, please find the comprehensive datasheet attached.

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