Until now, measuring and monitoring the status of Low Voltage (LV) distribution networks has been mainly ignored, even in the knowledge that this part of the grid represents the final connection to most electricity users. But today’s new upcoming requirements are forcing industry to redesign its management of the LV grid. Some of the key needs arising from this are met in the LV supervision system presented here. This technology monitors the status of feeders of the LV grid in the Secondary Substation (SS), offering a wide range of advantages and benefits for DSOs and final customers. Iberdrola has been testing this solution during the last five years, and after a broad experience has decided to push its standardization and deployment.
LV supervision cases and applications
Real-time monitoring (alarms)
This technology detects and communicates disturbances on the network per LV feeder, such as alarms due to a blown fuse, an event produced by an overcurrent, overvoltage or undervoltage, abnormal earth leakage presence, etc. The detailed information of the grid status is reported instantaneously to the operator, so the number (SAIFI) and duration (SAIDI) of power outages can be reduced.
Historical data from LV feeders, combined with hourly information from smart meter readings, and processed with new technologies, allows DSOs to analyse and model in detail LV network behaviours. This permits network operators to improve the LV network forecast (demand and generation forecast) and availability, as well as implement a predictive and preventive maintenance. This enhancement helps to design a more reliable, flexible and resilient distribution grid. LV supervision can generate the necessary data for a proper load balance between feeders and phases leading to a technical loss reduction.
A precise and detailed energy loss is calculated per LV feeder, by comparing the total energy sourced with the aggregation of the billed energy of all the meters connected to each line. In order to compute this calculation in a reliable way, an error free feeder and phase mapping topology information is necessary. An algorithm has successfully been developed, tested on field and put into production showing 100% reliability on the link data. The algorithm guarantees the association between customers and feeder-phase is properly updated, even when there are topology changes on the network. This new technology is independent from the communication model of smart metering technologies (PLC, radio, cellular, …).
An energy balance between hourly feeder profile and the aggregation of customer profiles determines the total loss per feeder in the LV network.
Additionally, to reduce non-technical loss, another algorithm has been developed to detect tampered meters by shunt. It has been tested on the field with great successful results.
Electric vehicle (EV) charging
With the LV supervision system, DSOs can determine maximum power drain for each user depending on network availability, thus, enabling semi-fast charging services that reduce EV charging time.
This technology will become an active part of the LV grid digitalization, offering DSOs the chance to improve their internal operations, extend services they deliver to end consumers and pave the way for upcoming flexibility market scenarios.
- Extract from the CIRED paper “Paper number 396 - Low Voltage supervision system: technology, applications, use cases and deployment". See www.ariadnagrid.com for more information