This article is about Data Concentrator Unit DCU. Here we put the basic definition of Data Concentrator Unit Principle with Data Concentrator circuit diagram. Following will be discussed Data Concentrator Specification.
Data Concentrator Unit Principle
A data concentrator is a software and hardware solution that connects a number of data channels with one destination. Data concentrators are found within substations to help manage many different data sources at one main source.
Data Concentrator circuit diagram
Data Concentrator Unit (DCU) In Advance Metering Infrastructure
This component, and therefore the DCU Application Layer and NAN Communications Layer, is optional, according to which architectural Solution (A or B) is specified (see §4 for more details). Thus, this section of the specification only applies for Solution A.
1. Basic Technical Data Concentrator Specification
1.1 Location
● All DCUs shall be located at the secondary side of a Distribution Transformer (DT).
1.2 Voltage Level Specification
Due to their location (Section 1.1), all DCUs shall be specified for 3-Phase, 3-wire, Low Voltage operation under the System Frequency and Voltage Design Basis set out in SAES-P-100, specifically Table 1.
1.3 Labelling
Each DCU shall be furnished with the following labeled information:
● Device Serial Number
● Manufacturer, Type, Model Number
● DCU Connection Diagram
● Current Rating
● Voltage Rating
● Frequency Rating
● Number of phases and connection type
● Year of manufacture
● Protective Class
● Ingress Protection Class
● Wireless Communications options (if any) provided
● Internal memory and hard-drive specifications
● Protocols supported (both to/from Smart Meters and to/from the NOC)
1.4 Time-of-Use (ToU) Pricing Function
The DCU shall:
● Be able to transmit pricing information to household customers downstream in the AMI and within their associated NAN.
● Receive and store (locally) pricing information in the form of XML-based data tables.
● Be able to assign financial value to each household (consumption, Micro-Generation) within its associated NAN, according to the prevailing metered data per home.
● Be able to store week-ahead tariff settings that can be communicated to home users upon scheduling the use of one or more of their appliances through their IHD.
2. Operational Requirements
2.1 Device Reliability
A. Standard Requirements
The DCU shall be:
● Manufacturer guaranteed for a usage period of at least 10 years.
● Able to continuously operate (outdoors) in extremely hot (up to 70°C) and humid (up to 95% non-condensing humidity) environments.
● Able to operate on a contingent basis in such a way that it temporarily mitigates the adverse effects of one of the following scenarios:
o Loss of WAN communications
o Loss of NAN communications
o Loss of mains power supply
o Assertion of corrupt firmware
B. Diagnostics
The DCU shall:
● Be capable of performing a self-test (initiated either remotely or via secure, direct, physical interaction).
C. Isolated Operation Requirements (Network Connectivity) e.g., as experienced during a loss of WAN communications.
The DCU shall:
● Have (at minimum) the capacity to store all data received locally, in the absence of utility communications, whilst operating with full data collection capabilities (for its associated NAN), on non-volatile memory for a continuous 7-day period.
D. Isolated Operation Requirements (Power Supply) e.g., DCU is mandated to operate from battery source during a loss of mains power supply.
The DCU shall:
● Send a “last-gasp” message to the Utility in the event that its battery is about to expire.
E. Firmware Requirements
The DCU shall:
● Be capable of receiving and installing a firmware update (initiated either remotely or via direct local access) without having to power down.
● Retain one previous version of firmware (non-active) as a local back-up.
● Autonomously revert from the default firmware version to the back-up in the event that the default version is corrupted (e.g., just after a new version has been uploaded).
● Manage firmware updates for Smart Meters within the NAN, as broadcast by the NOC.
F. Hardware Resets
The DCU shall:
● Retain any static data indefinitely whilst off supply.
2.2 Remote Utility Access
The DCUs shall:
● Be able to communicate remote Enabling/Disabling (of Load and/or connected Micro-Generation Modules) instructions from the Utility and conferring these commands onto the relevant Smart Meters under its control.
● Roll-back its own firmware (to previous stable version) upon receiving relevant encrypted instruction from Utility.
● Perform self-test upon receiving relevant encrypted instruction from Utility.
● Send acknowledgement that Utility initiated overrides have been successful or failed.
● Guarantee that any metered data sent to the NOC is packaged in such a way that the home energy practices of individuals within particular homes cannot be pin-pointed to any particular end user.
● Be able to provide demand forecasts to the NOC for their area by using scheduled information (input by householders using their IHD units).
2.3 Local Memory
The DCU shall:
● Clear internal memory allocated to a batch of metered data only (at least) 24 hours after a positive acknowledgement has been received from the NOC (as per §6.6.4.6).
● Have a non-volatile memory resource.
2.4 Time-Synchronization
The DCU shall:
● Possess an internal clock, synchronized with the AMI’s GPS-based, central timestamp.
2.5 Data Collection
The DCU shall:
● Handle the registration of all Smart Meters that connect to its associated NAN.
● Aggregate all metered data received from Smart Meters that connect to its associated NAN and which have registered with the DCU.
● Store all metered data (received from registered Smart Meters) locally (as per §6.6.2.1:C), prior to sending the data to the NOC.
● Facilitate data logging, via direct and secure access (as per §6.6.3 or alternative appropriate means) to locally stored meter data.
2.6 Data Privacy
● Metered in-home appliance data shall be retained at the NOC level so that the Utility can observe patterns in consumption patterns by device type.
● Data will be obfuscated by the intelligent element within the DCU so as to disassociate the identity of an end-user from user-sensitive data and/or device loading patterns (as per §6.6.2.2).
3. Interface with Hand-Held Units (HHUs)
See §6.5.6, replacing all instances of “Smart Meter” with “DCU”.
4. Interface with Neighborhood Area Network (NAN)
The typical layout of the Neighborhood Area Network (NAN) within a residential area is shown in Figure 6.
The requirements of the interface between a DCU and its associated NAN are as follows:
4.1 Connectivity
The Data Concentrator Unit DCU shall:
● Be equipped with a RS-485 interface, furnished with at least 2× RJ45 terminals.
● Be configured to transmit values to local Smart Meters to facilitate a near real time indication of energy consumption.
● Be capable of transmitting On/Off commands to NAN-enabled load switches/contactors, embedded within
Smart Meters for functions such as customer disconnection, load shedding or new customer connections.
● Configure a data table that facilitates switching in the NAN and allows for switching commands to be aligned with specified contractual periods of operation.
● Process last-gasps received from Smart Meters within its NAN and update its switch configuration table (mandated above).
4.2. A single, active interface shall exist between each DCU and its associated NAN layers.
4.3. The DCU shall manage and monitor the health of communications within its associated NAN.
4.4. Media and Protocol Conversion
The DCU shall:
● Translate messages relayed to it from the medium specified for the WAN (e.g., GSM/GPRS) to the medium specified for the NAN (e.g., PLC).
● Handle all protocol conversions (from messages between the WAN and NAN).
4.5 Distributed Control of Individual Homes
● Aggregated commands dispatched by the Utility shall be interpreted at the DCU Application Layer and relayed to Smart Meters located downstream at the End-Customer Application Layer.
● The following control shall be possible within the DCU Application Layer (these commands may be translated / disaggregated into commands for individual loads within the home at the End-Customer level, as per §6.5.7.3):
o Coarse On/Off Capability for End-Customer instances (Load Shedding)
o Disconnection/Connection of Micro-Generation Modules
o Sending load reduction targets to each End-Customer (translated by End-Customer Devices in the home, business, etc.)
4.6 Acknowledgement
The Data Concentrator Unit DCU shall:
● Confirm that data (metering data or Smart Appliances schedules) has been received successfully from Smart Meters in the NAN.
● Confirm that communications links between the DCU and Smart Meters are intact.
● Receive and interpret acknowledgements from its assigned Smart Meters in response to control messages having been dispatched.
4.7 Acceptable Protocols (between Domestic End-Customer and Data Concentrator)
● As per §6.5.8.3
4.8 Transport Layer
● As per §6.5.8.7
5. Interface with Wide Area Network (WAN)
5.1 Connectivity
● See §6.5.9.1, replacing all instances of “Smart Meter” with “DCU”
5.2 Acknowledgement
The Data Concentrator Unit shall:
● Send acknowledgement to the NOC that messages from the Utility have been received across the WAN successfully.
● Receive and interpret acknowledgements from the NOC upon having uploaded metering data from its NAN.
5.3 Transport Layer
For WAN communications, SAES-P-126 takes precedence over this document, where applicable. The following transport layer types are acceptable:
● Fiber-Optic (FO) cable
● GSM/GPRS
● VSAT
6. Robustness and Security
6.1 Electromagnetic Interference (EMI) Mitigation
● DCU operation shall be resilient to local magnetic fields and near-field EMI radiation from utility devices and local environmental sources.
● EMI immunity shall be tested as part of the installation process.
6.2 Tamper Proof Protection
The DCU shall:
● Have seals and a covering shall be applied such that the terminal and front covers cannot be opened, except by authorized maintenance personnel
● Possess different levels of password access. These should be provided within the AMI for electronic downloads of software/firmware updates, device resets, etc.
6.3 Environmental Exposure
The DCU shall:
● Be guaranteed for continuous operation within air temperatures of up to 70°C.
● Be guaranteed for continuous operation within humidity of up to 95%.
● Be designed with a minimum IP 54 Rating, as per IEC 60529 to protect against dust and water ingress. Please Be furnished with a Weatherproof Enclosure due to its outdoors location.
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