Improved MV and LV network automation solutions are necessary to face the constraints introduced by the increased amount of DER, to reduce energy losses and to maintain or increase the quality of supply.
Smart grids improve stability and security of electricity supply, in this new scenario in which the grid no longer has a unidirectional flow from generation to transmission to distribution to consumption
ZIV Distribution Automation Solutions are organized in 3 categories:
- MV Automation Solutions: RTUS, multifunction devices and sensors
- LV supervision systems
- Communication Solutions.
The introduction of advanced monitoring and control functions into the medium voltage distribution grid, required to achieve the data and capabilities demanded by the modern smart grid, requires specific technology developments. The distribution grid is vast, the number of equipment required is huge, and dependability, reliability, product cost and installation costs are key factors to take into account. As a result of this, new solutions are required in order to efficiently deploy smart grid functionality in the MV grid.
MV automation solutions in RMUs, reclosers, transformers with tap changers with automated setpoints, fault pass detection units and advanced protection devices, sensors and communications, are all part of the technology components which will be implemented in the MV grid to deploy the smart grid of the future.
The LV grid will benefit from the millions of smart meters which become LV monitoring points generating big data that can be processed and analyzed to improve grid operation and optimize the efficiency to lower CO2 emissions.
The Benefit: the overall efficiency of the grid is increased both in terms of operation and in terms of performance and capacity.
These supervision systems offer an enormous amount of information to be integrated and processed in the corporate information systems of the distribution companies. LV network supervision solutions are a cost‑effective alternative to increase the distribution grid capacity due to better control and monitoring of the LV grid.
Additionally, LV advanced supervision systems enable the implementation of advanced low voltage monitoring functionalities such as blowout fuses, fraud detection, feeders load unbalances and quality of supply assessment.
Thanks to the MV supervision systems, utilities can detect the faults and react much faster, which reduces in a huge way the outage unavailability records. The integration of the renewables in MV is also improved, as the online control of the level of the voltage allows to tune it on the tap changer in case of a change because of a renewable plant.
A Case study: Iberdrola’s STAR project
Iberdrola’s STAR project is a huge smart grid project consisting on the massive deployment of smart equipment in different locations of medium and low voltage grids. This involves millions of smart meters installed at low voltage end users, dozens of thousands of secondary substations equipped with AMI concentrators, RTUs, and communications integrated in RMUs.
The MV and LV supervision and operation are integrated in a single network inside the Secondary Substation. The information coming from the smart meters, LV and MV supervision is sent upwards in the network architecture up to the control center of the distribution company. The amount of the information is enormous, providing online and detailed knowledge of the whole MV and LV grids, from home users to Secondary
Beyond AMI: Low Voltage Grid Operation
Smart electricity meters are a reality. Smart meters combine different technologies that range from current/voltage measurements, energy and power calculations … to the integration of different telecommunication interfaces (powerline, wireless or wired communications).
A good example of the application of different telecommunication interfaces is the ESMR5 smart meter that ZIV is developing for Enexis.This smart meter integrates a wired interface to communicate with the customer, with wireless M-Bus communication (frequency range of 868Mhz) to collect data from other meters in the vicinity (water, heat or gas meters). It integrates LTE telecommunications to share information with the central system using the DLMS protocol.
In all the countries that have decided to deploy smart meters, both customers and DNOs are achieving important benefits using this technology. Electricity customers can receive near real-time information
about their consumption, allowing them to implement energy efficiency policies.
Distribution network operators can gather data about their low voltage network which improves their grid visibility.
LV supervision, beyond AMI
Smart meter vendors have had to surmount many technological challenges in order to provide integrated advanced functions in a single meter device at a very competitive cost. The good news is that the technologies developed as a result of this effort have opened the door to a new family of products focused on LV grid operation.
In this article, we would like to highlight how LV grid visibility can be improved by adding LV smart devices at specific grid locations such as LV feeders and LV branches. These LV smart devices make use of the technology already available in smart meters to provide additional data so that distribution network operators have a clear view of the LV grid status and condition.
Operating the grid to improve quality of service
Continuity of supply is a must for DSOs/ DNOs, thus a reduction in the SAIFI and SAIDI figures is one of the indicators used to show performance improvement of the grid operators. Loads, such as electronic devices, appliances, inverters… which are sensitive to power disturbances are increasingly being connected to the grid. Consequently, the measurement of power quality (PQ) parameters is becoming essential for network operators to
minimise the impact of voltage sags, swells or harmonics on a customer’s installation.
Continuously monitoring the LV grid enables early detection of power outages and power disturbances that may have an impact on a customer’s power quality. Status of blown fuses, loss of neutral and other events which are detected and reported to the network operator as soon as they occur, minimising
the interruption time.
Therefore, using these devices, which are available on the LV network to signal voltage outages by passing this information on to the network operator will allow action to be taken to reduce the interruption time. One step further is to automatically operate the grid combining the LV information with data provided by fault passage indicators and MV automation systems to restore the system
to a healthy state.
To take advantage of the possibilities provided by the new generation of smart devices and sensors connected to the LV grid and to obtain these data, they must be integrated into the utility operation systems. Utilities have reported a reduction of up to 70% in the SAIDI index for the 2001-2016
period with these improvements. Furthermore, up to 35% reduction in operational expenses per customer have also been achieved.
Improving efficiency, reducing losses
Energy strategy for 2030 in the EU fixes a target of 27% energy savings compared to ‘business as usual’ figures. Meeting this target requires actions to improve the overall efficiency of the distribution networks. Energy losses have always been a concern for utilities. There is a direct economic impact on the business. Mandates of the EU and member states nails this figure down and formalises a commitment.
Technical losses, measurement errors and fraud detection require accurate and reliable
information on the flow of energy. The most frequently used method calculates the balance
between the energy delivered by a transformer or a feeder and the total energy metered in smart meters connected to the feeder or transformer. Resolution of the data and its mapping to the grid topology influence the accuracy of the results of the investigations.
Feeder monitoring produces high value information for LV grid operation and maintenance providing online updated network topology. This method avoids the cost of field work by the crews and dramatically reduces the time required to update the information in the utility’s GIS. For power line carrier (PLC) enabled meters, ZIV has developed a technique for the identification of which smart meter is connected to which LV feeder based on a measurement of the strength of the powerline communication signal received from each meter in the transformer substation. This technique produces excellent results in the field.
Efficiently managing network assets
Load imbalances among LV grid phases and/or feeders impacts efficiency because it prevents the full capacity of the system being exploited. The optimal load arrangement is therefore determined by combining smart meter data, feeder and transformer output measurements with network topology information. As a result of this optimisation, the life of the assets is prolonged, deferring investments in unnecessary network extensions. Similarly, continuously monitoring MV/LV transformers provides data to determine the efficiency, usage factor, thermal stress and life expectancy. Based on this information, DNOs can make decisions to extend the life of the transformer in a certain location, replace it with a smaller or bigger one, or install a new one with lower losses.
RES/DER, storage and EV integration
The EU has also stated in its 2030 energy strategy that there must be a target of at least 27% share of renewable energy consumption. Member states have subsequently adopted renewable energy programmes to meet this requirement. Renewable energy connected to LV networks, especially in residential areas (urban or rural) cause effects for which the networks were not originally designed. Similarly, other distributed energy resources can also affect grid operation. New loads, such as electric
vehicles and storage, demand new solutions to be effectively integrated in the grid. LV supervision can be the cornerstone for the integration of new influences into the network and improve the quality of supply and service for every customer connected to the grid.
ZIV solution for LV supervision
The ZIV solution consists of two devices: the LV feeder supervisor (5CTI) and the LV controller (4CCTI).
The 5CTI feeder supervisors provide information to calculate energy losses in a transformer and LV feeder and compare this with average network losses to detect deviations, therefore indicating irregular network performance. These particular locations are further investigated to determine whether the inefficiency is due to fraudulent consumer connections or poor performance of network components. The 4CCTI LV controller is connected to the 5CTIs via a RS485 bus and provides valuable information such as power quality measurement, earth fault detection, fault recording and a meter-to-feeder
mapping algorithm which gives updated LV network topology information back to the network operator.
These solutions are based on AMI technologies successfully deployed all over Europe.
ZIV is participating in many of the major meter rollouts that are taking place in Europe and is a reliable partner to make your smart LV network a reality.
About ZIV LV supervision solutions
The exponential increase in the adoption of Distributed Energy Generation such as Photovoltaic (PV) and Wind has introduced significant challenges for DNOs when it comes to the control of network voltages and power flows at all voltage levels on their network. At times and when network conditions dictate, Generators are constrained. This results in inefficiencies in operation as well as lost generation.
The Genesis family of Generation Management Controllers have been developed by ZIV Automation in response to industry demand for the intelligent management and control of Distributed Generation.
Genesis Controllers provide localised independent control of Distributed Generators in response to real time changes both at a local site level and to the network. The Generation controller provides a greater degree of control over both the constraint level and constraint type applied to a particular generator. It also allows for the Distributed Generator to operate in a number of alternative modes assisting the DNO to optimise the management of their network.
Genesis Generation Management Controllers from ZIV Automation allow the DNO to help optimise their network usage whilst assisting Distributed Generators to Maximise their Generation Capacity.
The Controllers can be totally standalone or easily integrated into an Active Network Management System. The Genesis Family of Controllers are modular compact Controllers providing a very cost effective solution for localised control of Distributed Generators.
product datasheet: DAS_HANMI1611C
Case related: An Advance Network Management System to Integrate Distributed Generation in ESB (Ireland)
To provide a control system that:
- allows control of windfarms export by the utilities to provide the necessary voltage support whilst respecting the networks voltage and thermal constraints.
- to monitor analogue and digital values from specific points, and make decisions on the network to determine if the connected distributed generation power stations are allowed to generate at full capacity or to be constrained
- To provide an ANM schemes, based on communications if required, with centralized or distributed architectures, to manage the power flow on the network.
Cauteen 110Kv substation
- Four substations connected together with a distributed ANM system to control the amount of the VAR exported parallel into the TSO (EIRGRID) as well as the DNO (ESB) systems.
- Power flow control systems in more than 200 points in NPG (Northern power Grid) and WPD (West Power Districts )in the UK. Several locations were the power flow in Wind and Solar farms are connected to these two DNO systems.
The described system has allowed our client ESB (Ireland) to accelerate the integration of Distributed Generation sites onto their distribution network whilst managing the impact that this additional generation has on network operations.