The Linky Smart meter
The Linky smart meter is at the heart of the NICE GRID project, enabling in particular to retrieve historical data and to control customer’s domestic appliances.
The Linky smart meter, the first stone of smart grids
This meter of a new generation measures remotely and on a regular basis the electricity consumption and the generation of households in order to optimize the management of the electricity distribution grid.
The features of this new smart meter are essential to develop innovating smart grids solutions in France.
The service level obtained in NICE GRID for collecting data and sending control commands to smart meters deployed in Carros is around 95%.
The Linky smart meter
As of May 2015, 2350 meters were deployed in Carros.
An innovating communication architecture
The Linky smart meter is able to receive orders and provide data remotely, without requiring the presence of a technician. In this way, the meter communicates with a data concentrator, which is a mini-computer installed at the secondary substation managed by Enedis, via a Power-line communication (PLC). The concentrator is directly linked to the Enedis supervision agency, based in Lyon.
A focused deployment
In 2012, the first households equipped with smart meters were the households of the 7 solar districts which concentrated half of Carros’ photovoltaic generation.
Thereafter, the deployment carried on in the area selected to experimentations of load shedding. This district concentrate inhabitants equipped with electric heating, and collective housing, street lighting and electrical vehicle charging stations. These are all essential components to perform experimentations.
86% of this area’s inhabitants are equipped with electric heating, that’s why the electricity supplier EDF proposed several adapted offers which meet the need of shedding load. This is one of the major levers to face the consumption peak.
Several strengths for the project
Better awareness of the electricity consumption and production
• A monitoring portal of participating customers consumption
With the consent of the customer and by metering systems, load curves are securely and daily transmitted to the aggregators which offer participating customers a portal to monitor their consumption via internet.
• Generation Forecast set daily
Historical measurements have been used to forecast accurately and daily the individual consumption and generation of customers concentrated in solar districts. To achieve this, each day, the metering system transmitted to the NICE GRID forecast platforms load and generation curves of customers.
The control of equipments through information transmitted by the meter
• Prive incentives
During summer experimentations, volunteer customers in solar districts have been able to take advantages of additional off-peak hours between 12 noon and 4 PM, during the 40 sunniest days. This offer is sent the day-ahead to each participating customer, the information was sent to the meter which measured the consumed energy with a dedicated index.
• Dry contact control
For customers equipped with electric hot water tank, an order is sent the day-ahead in order to trigger the water heater in the following day. By this way, the water heater was triggered during a time ranging from 30 minutes to 4 hours. This activation took place in group of customers, in order to smooth the load curve at the district level. For street lighting, during consumption peak, the meter’s dry contact served to actuate, the day-ahead for the following day, the dimmer switch to reduce the light intensity.
• Transmission of a peak reduction signal
The meter’s remote customer information (TIC) output provides the customer several information including the current peak consumption period. In NICE GRID, the day-ahead of consumption peak days, the energy supplier sends a peak reduction signal in order to control electric heating via equipment downstream from the meter.
A better understanding of the low-voltage distribution grid
• Connecting phase
The smart meter enables to improve the accuracy of the customers cartography.
• Voltage measurement
A high photovoltaic generation can raise locally the voltage, the Linky smart meter can consequently play a warning role. The meter communicates voltage measures when it exceeds a specific threshold; this measurements are primordial to monitor the electric grid of solar districts in Carros.
Interface « visibilité conso » for a residential customer
Pose d’un compteur communicant Linky
Store on the electric grid, the guarantee of a flexible grid
These four storage systems, connected to the electric grid of Carros, have shown the wide range of flexibilities they can offer: reduce peak demand the coldest days, store the surplus of photovoltaic generation the sunniest days, and island temporarily a district of the main distribution grid.
• The 1 MW / 560 kWh storage system
Installed at the primary substation supplying Carros, this system was used only to reduce the peak demand the coldest days by injecting on the distribution grid the stored energy. The storage system of 1 MW was one of the most important in Europe in view of its storage capacity.
• The 250 kW / 620 kWh storage system
Installed at the secondary substation “Dock Trachel” in the industrial area of Carros, this storage system has enabled to island a district (supplying it autonomously for a limited duration of time), to reduce peak demand the coldest days and to store the surplus of photovoltaic generation the sunniest days.
• The two 33 kW / 106 kWh storage systems
Installed in residential solar districts, these “community” storage systems contributed to reduce peak demand the coldest days and to store the surplus of photovoltaic generation the sunniest days.
The 33 kW / 106 kWh storage system
Installation of the 250 kW / 620 kWh storage system
Installation of the islanding storage system in the industrial area of Carros
Influence of storage on the grid voltage
Voltage measurement at the level of the 33 kW / 106 kWh community storage system
For the prosumers, storing energy at home, an additional flexibility
18 participating customers of NICE GRID were equipped with a residential storage system consisting of a SMA converter and a Saft Li-Ion battery of 4kWh. These systems connected to the domestic grid such as another household appliance, allowed the prosumer to play a proactive role in reducing winter consumption peaks, by discharging the battery and in reducing the summer injection peaks during the sunniest days by charging the battery.
Installation of the first residential battery
Batteries and converters, at the heart of the storage system
A storage system is characterized by its power rating, equivalent for instance to the amount of clients to supply, and by its energy, which can be illustrated by the period during which clients are supplied: two parameters to select according to the storage use cases.
A storage system in NICE GRID project consists of one or several battery racks combined to one or several power converters.
Converters transform direct current into alternate current with an appropriate voltage to connect the system to the electric grid.
Lithium-Ion, a cutting-edge technology
NICE GRID has chosen Lithium-Ion batteries, one of the most advanced solutions. Indeed, Lithium-Ion batteries can charge and discharge electric energy by using a chemical reaction based on lithium ion. The main features of this technology are its high energy density (energy per volume unit) and its mass energy (energy per mass unit).
Those characteristics make this technology one of the better among the current existing solutions, to supply mobiles appliances (Smartphone…) or vehicles (electric or hybrid vehicles).
The power converter, an essential component
Lithium-Ion batteries operate with direct current where electrons circulate always in the same direction. However, the electric grid supplies alternate current; electrons change direction each10 milliseconds. Thanks to power converters, the direction of electrons changes that allows to charge and discharge the battery from the grid.
NICE GRID project has used several models of converters according to the power range.
The Network Energy Manager (NEM), at the heart of the project
The Network Energy Manager (NEM), developed by GE Grid Solutions, has been firstly operated in March 2014. This computer plays a central role in solving grid constraints, in winter and summer by offering the requested flexibilities.
Based on generation and consumption forecasts and grid operators requests, it requested aggregators to offer flexibilities which meet operators demands. This NEM is like a local flexibility market consisting of 2 buyers (Grid operators) and 3 vendors (3 aggregators).
Presentation of the NEM by GE, European Utility Week in Vienne, Autriche - Nov 2016
Aggregators, interface between the NEM and the customers
Aggregators ensure the link between flexibilities (control of water heating, industrial processes, storage systems on the grid) and the Network Energy Manager (NEM).
Among their main functions, let’s talk about the aggregation of customers’ contributions in order to build offers which will be proposed by the NEM or the control of flexibilities meeting grid needs.
NICE GRID relied on 3 aggregators:
• The residential aggregator EDELIA which controlled flexibilities at residential customers’ premises (water heating, batteries…) through the Linky meter infrastructure or a box for the batteries.
• The business aggregator NETSEENERGY which controlled the processes of 12 participating industrial clients and the public lighting of 8 streets in Carros.
• The storage aggregator which was in charge of the 4 grid storage systems.
Generation and consumption forecasts
The Network Energy Manager (NEM) relies on photovoltaic generation and consumption forecasts. This 2 platforms use historical data of generation, of consumption (through Linky) and weather forecasts as input data.
Then, forecasts are integrated in the NEM in order to estimate the need of grid flexibility for the following day.
The residential water heating, an energy tank
The control of the hot water tank proceeded remotely by EDF, without any further equipment, through an information sent to the smart meter Linky.
In this way, several times, between 12 noon and 4 PM during high solar generation periods, hot water tank were triggered, acting like a thermal storage.
Residential batteries, a first step towards self-consumption
Customers who subscribed to the « Smart Solar Equipment » offer gave their consent to EDF to control automatically the installed battery.
To proceed this automatic control, EDELIA installed an Energy Box which enables information exchanges between the aggregation platform and the Saft Battery through the SMA converter. It directly communicates with consumption and generation meters. Thus, the box sent appropriate charge/discharge orders according to the context: if the photovoltaic generation is important and the consumption low, a charge order is sent. Conversely, in order to face a consumption peak, the household equipments consume the energy stored in the battery.
Electric Heating supervision, an essential leverage to reduce the consumption peaks
Participating customers who signed «Electric Heating Control » contract, agreed the automatically control of their electric heating by EDF (via NKE, EDELIA and the Linky IT).
The system is controlled through a signal sent by the Linky smart meter, then this signal is detected by a dedicated component, installed in customer home. This device is in charge of cutting off or reducing the consumption of the electric heating.
The supervisions of several tertiary and industrial devices
Air-conditioning systems, air handling unit, water heating, cooling unit… 12 participating industrials agreed to have an automatical control on these devices by the business aggregator Netseenergy.
The supervision of the street lighting through Linky
The public lighting of 8 streets in Carros was supervised during the consumption peak, with support from the Nice Côte d’Azur metropolis. An interface connected to the Linky smart meter and a voltage regulator of the company Augier have enabled this automatically control.
The solar transformer, a turnkey and independent solution
The solar transformer, combination of a MV/LV transformer, an on load tap changer, a solar radiation sensor and a controller, has been installed in one of the secondary substation of the 7 solar districts in Carros. Its main function is to stabilize the voltage in order to be able to connect more photovoltaic generation in the district without any risk of overvoltage for the customers.
Installation du transformateur solaire, fruit d’une innovation entre Schneider Electric et les équipes d’Enedis – novembre 2014
Fonctionnement de l'asservissement solaire du transformateur solaire
The Broadband over Power Line (BPL) communication
Storage systems, advanced measurement devices, meters, solar transformer…All this innovating components are allocated on the grid, bus how make them securely and in real time communicate among themselves?
The solution is the broadband over power line communication. This communication protocol uses electrical wiring to simultaneously carry data and electric power. Thus a signal, with a frequency of 2 to 12 MHz and carrying data, is superposed to the electric signal of 50Hz.
The Broadband over Power Line (BPL) communication