Data Concentrator Unit
DCU is a interface between smart meters and head end system
(HES) which collects data from various smart meters and sends it to
HES over a communication medium.
Basic features of DCU :
It should establish secured connection for two way data
transfer.
DCU shall be consist of two communication network.
- One for underlying devices (smart meters)
- another for upstream applications
It shall send meter data to HES – On demand & scheduled
basis at cyclic time intervals
Immediate report to HES about critical events occurance –
fault detection.
It shall support group of meters reading / configuration.
The DCU shall support at least 1000 smart meters.
The DCU shall function and communicate with the installed
meters when placed/fixed away from the nearest electronic
smart meter by a minimum distance of 500 meters.
The DCU shall interface with connected meters and HES using
bi-directional communication.
The Data Concentrator meter reading cycle shall be
programmable by HES.
If communication between the DCU and HES has failed,
reestablishment of communication shall be attempted, during
which the DCU shall store all of the scheduled meter reading
records. The storage media (nonvolatile memory or any other
storage devices) shall be sized to retain data for all the meters
managed by the DCU.
The Data Concentrator shall be able to send commands to the
meters and to recieve the acknowledgement messages.
The DCU shall detect the presence of newly-installed meters
in DCU’s network, register the meters in network map
automatically and synchronize the installed meter RTC with
DCU’s internal RTC.
Functional Block diagram of DCU
Figure 1: Functional block diagram of DCU
Key functions of DCU:
1. Data Collection :
* Collecting data about energy consumption, sensor readings,
demand data reading, billing data reading, key user profile
data, event reading etc.
2. Data Storage and Processing
* It uses storage media(non-volatile memory or external
storage media) for data storage.
* Basic processing of collected data is done before
transmission
Filtering – Removal of noisy and unwanted data.
Aggregation : Summarizing the data from multiple meters.
Buffering – data buffers to prevent loss of data during
transmission.
3. Data Transmission
* WAN network is used for data transmission between DCU
and Head End Systems. The backhaul network technologies
like Wifi, cellular (3G/4G) network, GPRS are commonly used
for data transmission between DCU and upstream
applications.
* Aggregated data is transfered to HES.
* In case of GPRS/3G/4G backhaul, DCU shall support SIM
card of any service provider.
4. * It should periodically monitor meters and retry and reconnect
in case of failed connection.
* After power interruption, on restoration of power supply, DCU
shall establish communication with smart meters and HES.
5. Remote Management
* The ability to configure the meter parameters
* DCU shall capable of configuring the meter configurations of
multiple smart meters at single time.
* It shall support firmware upgrade of the system.
* The Data Concentrator shall regularly check communication
of the meters to assess the health of the network
communications.
6. Security
* The DCU has tamper detection capabilities to detect
abnormal events and alarms when it notifies the defects.
Figure 2: DCU Communication in AMI system
DLMS 3 layered structure
1) Modelling
* Meter data & rules for data identification.
* It defines COSEM objects and OBIS identification codes.
2) Messaging
* Provides communication services and protocol for mapping
of elements of data models to Application Protocol Data Units
(APDUs)
3) Transporting
* Services and protocols for transportation of messages
through communication channels.
Data Modelling in DLMS
