In May 2020, the Australian Renewable Energy Agency (ARENA) announced AU$490,629 in funding for transmission network operator Powerlink Queensland.
The purpose of the funding is to investigate technical, commercial, and regulatory solutions to address system strength challenges.
As renewable energy (RE) gains traction, power grid regulators and operators are scrambling to find viable solutions to prevent variable energy sources destabilizing the power grid.
Power engineers need grid-wide data to help them formulate solutions that take into account all factors that impact power grid resilience.
What is Power Grid System Strength?
One of the main difficulties in power systems, is that the amount of active power consumed plus losses, should always equal the active power produced.
If more power is produced than consumed the frequency will rise. If more power is consumed than produced, the frequency will drop.
Making sure the frequency is constant is usually the task of a transmission system operator. In some countries (for example in the European Union) this is achieved through a balancing market using ancillary services.[20] [Reference: Wikipedia]
Powerlink’s study will look at addressing system strength challenges by exploring the merits of several technical solutions. Business and regulatory models will also be considered to facilitate lower-cost solutions and remove commercial barriers.
Transitioning to a Distributed Grid without compromising system strength
As the energy industry transitions to a lower carbon future, power grid resilience has emerged as a prominent challenge.
There are many factors that can impact power grid resilience The challenge being faced by energy regulators and grid operators involves integrating renewable energy sources. Distributed renewable energy sources, such as rooftop solar panels, are a growing consideration due to them being unmanaged.
Most renewable energy sources are variable in energy generation. The variable nature becomes a significant challenge as RE sources grow to provide a larger share of energy generation. How is this variable energy managed and controlled to match energy demand?
It is a tough technical challenge that engineers face.
System strength is an essential grid security service and represents the ability of a power system to remain stable under normal conditions, and to return to a steady state following a system disturbance. Current wind, solar PV and battery technologies do not typically contribute to system strength.
The project will explore several existing technology options for managing system strength and supporting the integration of renewables into the grid. These include installing synchronous condensers, changing inverter settings or strengthening transmission infrastructure.
Grid-wide energy flow data-sets are essential for engineers to specify control and management mechanisms.
ARENA CEO Darren Miller said system strength is a complex and technical subject that has evolved over time, and this project will help provide a clear and common understanding of the system strength concept, how it can be managed and network implications.
“AEMO’s Integrated System Plan has shown that, in many situations, a centralised approach to managing system strength would be more economic than developing individual solutions for each wind and solar farm.”
ARENA CEO Darren Miller
“The ongoing study will aim to help wind and solar developers, facing difficulties with grid connection due to limited system strength, and would help reduce project risks, delays, and costs.” said Mr Miller.
“In some cases, developers can be forced to install synchronous condensers as a local source of system strength which can come at a large cost to developers and be project-specific solutions, which are unlikely to be economically efficient.”
Powerlink’s study is expected to be complete in late 2020.
Using OTELLO to solve the Rooftop Solar problem.
In the case of DREDS (Distributed Renewable Energy Devices) such as rooftop solar, where supply and demand prediction is a particularly challenging problem, OTELLO presents a possible solution.
There are a number of Energy Disaggregation solutions for home power consumption efficiency. With OTELLOs’ unique edge computing capabilities, energy disaggregation algorithms can be adopted and applied at a mini-substation level.
A localized, neighbourhood energy disaggregation profile can be generated. This data can then be used in upstream distributed demand prediction models.
Combining mini-substation disaggregation data profiles, with OTELLO’s unique Sentinal® functionality, utilities can deploy localised, automated protection mechanisms. An example would be controlling a section of neighbourhood grids that are generating more energy than is being consumed.
This data based approach solves the problem at the edge, rather than trying to control individual rooftop solar installations.
Introducing OTELLO – Grid-wide, real-time and centralised power data-store.
Developed in Cape Town, South Africa, OTELLO is an innovative grid management system developed to meet Africa’s steep energy challenges. It is a solution in two parts – a device installed across the network, and a software platform that visualises the data and provides real-time notifications when network performance moves out of accepted safety thresholds.
This centralised, synchronised, real-time, and historical power grid data, allows engineers to ‘see’ the power grid as never before. When it comes to engineering grid system resilience, a history of the events that impacted grid resilience is essential to strategising and developing solutions.
Each OTELLO metering and control device has an onboard edge computer, which allows data to be processed locally, while simultaneously streaming it to a central data store. With a built-in GPS clock that is time synchronised to within ±100ns from absolute time, the full fleet of devices work together in perfect harmony, delivering the full picture of network performance.
OTELLO records and reports on a comprehensive set of RMS, phasor, harmonic, environmental & synchrophasor data, encompassing over 9,000 parameters.
OTELLO’s data visualisation platform reports and interprets the data for the end-user. Available for all smart devices, OTELLO will notify the appropriate team members at the moment anomalies occur on the network. If storm clouds suddenly begin to form over the city and solar supply drops rapidly, OTELLO will send emergency push notifications and emails in real-time to the people who matter.
Beyond emergency notifications, OTELLO’s unique capabilities also unlock:
- Remote grid management and protection mechanisms
- Wildfire detection and prevention
- Safe transition to the distributed energy grid
- Proactive power quality compliance monitoring
CREDIT: This article was adapted from the article by Energy Source & Distribution Australia, titled ‘ARENA backs Powerlink system strength study‘
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