B Duncan Ltd
Power Systems Engineering
Protection, control, and SCADA engineering for utilities and switchgear vendors.
Capabilities
What we do
Protection & Control Firmware
Firmware for protection relays, reclosers, and distribution control equipment.
SCADA & Communications
Integration with SCADA, PLC, and DCS systems over DNP3, IEC 60870, and Modbus.
Field Failure Investigation
Instrumenting deployed controllers to find the cause of intermittent faults in service.
Power System Modelling
Computer representations of electrical systems to analyze and predict behaviour.
Power Quality Analysis
Harmonics, voltage quality, and power-factor investigation.
Commissioning Support
Support for protection settings, configuration, and commissioning of new equipment.
Field forensics
Finding faults in equipment already in service
The hardest problems in this sector are not in development. They are in equipment installed across a network, failing intermittently, where the fault cannot be reproduced on a bench and the units cannot easily be recovered.
Our approach is to instrument rather than speculate: add monitoring firmware that captures what the device is actually doing, deploy it to affected units, and analyze the returned data until the cause is identifiable.
Modernization
Legacy systems and the transition
Distribution networks run equipment with service lives measured in decades, alongside SCADA integration and smart-grid functionality added long after the original design. We implement new functionality, resolve performance problems, and keep legacy equipment running reliably through the transition rather than treating replacement as the only option.
Why us
Why choose us
Power-sector track record
Years of work with distribution utilities and global switchgear vendors on protection and control products.
Firmware depth in the domain
Not power engineers who subcontract the software, or software engineers learning the sector.
We find faults in deployed equipment
Root cause located on deployed power-grid controllers that a client team had been unable to resolve.
Independent & impartial
Findings that stand up to scrutiny from manufacturers, insurers, and legal proceedings.
Protocols
Protocols and equipment
Communications
DNP3, IEC 60870-5-101 and -104, Modbus RTU and TCP, TCP/IP, serial and IP radio links, with a working understanding of the OSI model where a custom protocol is needed.
Equipment
Pole-mounted auto-reclosers, protection relays, sectionalisers, distribution control equipment, and the configuration software that goes with them.
Network types
Ring networks with directional protection, radial networks with over-current protection, medium-voltage distribution.
FAQ
Common questions
Do you work for utilities or for equipment vendors?
Both, and they are different engagements. For vendors it is usually firmware development or a design review inside the product. For network operators it is usually investigation, commissioning support, or configuration on equipment they have bought.
Can you work on equipment you did not develop?
Yes, and that is most of this work. It generally starts with instrumenting the device to capture what it is actually doing, because field faults in this sector rarely reproduce on a bench.
Which SCADA protocols do you work with?
DNP3, IEC 60870-5-101 and -104, and Modbus. We have also developed custom protocols where a system needed something the standards did not cover.
Is this related to your EMC work?
Closely. Distribution equipment operates in an electrically hostile environment, and a good share of the intermittent faults we investigate turn out to be interference or earthing problems rather than software defects.
Related services
Electrical System Diagnostics
On-site fault investigation when installed equipment is misbehaving: intermittent failures, VFD interference, and earthing issues, on your site anywhere in New Zealand, with every instrument we need brought to you.
Power Electronics
Converter, inverter, and power-stage design at the equipment level, for the protection and control products utilities and switchgear vendors buy.
Safety-Critical Firmware
Protection and control equipment firmware developed and audited to recognized safety standards, with the traceability and evidence to back it.
Discuss a power systems project
Whether it’s product firmware, a field fault, or a modernization programme.