Centralized Schemes

Utilizes a system wide Distribution Management Systems (DMS) that analyzes the entire network to identify the best way to reconfigure the feeders to restore power after a fault. 

Decentralized or Substation Based Schemes

Analyze smaller sections of the network and does not require information about the larger distribution network to reconfigure local sections of the grid that are experiencing outages due to faults.

Through implementing a D400-DA substation based FDIR scheme, communications needed for monitoring or reconfiguring the network only need to extend from the field recloser and switch controllers to the substation where the D400-DA is located. While communications can be sent back to a Control Center for SCADA management, the complete reconfiguration of the network can be done without a backhaul communications infrastructure. When large scale events occur that can cause multiple utility wide problems, the D400-DA substation based FDIR solution will continue to operate and reconfigure the network even if backhaul communications are lost.

The D400-DA substation based FDIR solution can automate both Looped and Multi-Ended feeder network configurations. The D400-DA can typically restore power to unfaulted sections less than 1 minute after a fault occurs, fast enough to prevent the outage affecting SAIDI and SAIFI indices.

This D400-DA solution provides a scalable solution for automating from as few as two and as many as twenty circuits or feeders with a single D400-DA. With this scalability, utilities have a cost effective solution that can be incrementally rolled out feeder by feeder or just installed on circuits that are causing the most reliability problems. One D400-DA can automate these twenty circuits whether or not they are emanating from one substation or from multiple substations, as long as the D400-DA can communicate to the controllers in the field.

Feeder Sectors

Each D400-DA can monitor and automate up to twenty feeder sectors. Each sector is defined as a feeder that begins at a breaker and ends at a normally open tie point. The D400-DA that is monitoring a particular sector will be responsible for isolating that sector in the event a fault has occurred on it. This same D400-DA will also be responsible for controlling the tie switches to other sectors in the event that more load will be added to it to restore adjoining dead sectors.

Devices Controlled

Each D400-DA can communicate with and control up to 100 devices found within the sectors it is monitoring. Devices interfaced with it may include protection relays, recloser controllers, switch controllers and fault circuit indicators.

The D400-DA has two main modes of operation for isolating and reconfiguring distribution networks: Automatic Reconfiguration and Operator Assisted Reconfiguration.

Automatic Reconfiguration

 – In Automatic Reconfiguration mode, the D400-DA will identify outages on its monitored sectors and take action to restore power to the maximum number of customers as possible. It performs the actions without any interaction required from system operators.

Operator Assisted Reconfiguration 

– In Operator Assisted Reconfiguration mode, the D400-DA will require confirmation that system operators agree with the recommended action before these actions are carried out. This mode of operation is often used by utilities for an initial trial period of time to have their operators get comfortable with the D400-DA recommendation before going into full Automatic Reconfiguration mode. 

Reconfiguration Triggers

While the D400-DA is monitoring its feeders, there are several sequences that will initiate a reconfiguration action: 

• Protection Lockout: The operation of a protection function on a protection relay or recloser controller
• Loss of Voltage: The voltage on a sector has dropped below the programmed voltage threshold for an extended period of time defined by the utility
• Loss of Voltage After Fault: An intermediate loss of voltage after a downstream overcurrent detection

The D400-DA system configuration software is an easy-to-use online tool that allows for system modeling and FDIR sector configuration. When being used in Operator Assisted Mode, this tool can be the operator interface for acknowledging or rejecting reconfiguration scenarios proposed by the D400-DA FDIR system.

When a reconfiguration action has been triggered, the first course of action the D400-DA will take is to isolate any faulted sections on the line. Isolation actions will attempt to minimize the number of customers falling within an isolated section. When the D400-DA is in Operator Assisted Mode, it will give a recommendation to the operators on the best course of action to take to isolate the fault. If the operator does not agree with the recommended action, the D400-DA will calculate the next optimal scenario and propose that to the operators.

Isolation on Sectors with Distributed Generation

When a fault occurs on a sector of the line, the D400-DA will open all of the available switches to completely isolate the fault. On radial feeders or laterals, if additional switches are located downstream of the fault, the D400-DA will also open those switches to prevent any other sources such as distributed generation that may back-feed the fault.

Once the D400-DA has ensured any faults are isolated, it will attempt reconfigure the network to restore power to as many customers as possible. When operating in Operator Assisted Mode, the D400-DA will first ask for confirmation from the operator before taking any action. If the operator does not agree with the recommended action, the D400-DA will calculate the next optimal scenario and propose that to the operator.

Historical Load Modeling

To ensure that the source being used to re-energize a sector of the feeder can support the additional load, the D400-DA calculates the short term power requirements based on a 15 minute sliding peak demand window with 1 minute resolution. The D400-DA also identifies the long term load requirements using a 30 days sliding window with a 1 day resolution and a 15 minute averaging period. 

Dead Line Verification

Before reconfiguring the network, the D400-DA will verify that the voltage on the dead sector has dropped below configurable thresholds to ensure that the line is still not energized due to any residual distributed generation sources. 

Alternate Protection Groups

Before reenergizing a line, the D400-DA will alter the setting groups on any recloser or switch controllers on the line so that the protection functions will be coordinated for the new loads and direction of power flow.

The D400-DA is built on a flexible, high performance, expandable disk-less and fan-less platform that is powered by a 1.0Ghz processor. 
Two Ethernet networks are supported with separate multiport switches. An IRIG-B format time protocol input/distribution module is also supported. Isolated serial port media is selected for each pair of ports.

The D.20 RIO Distributed I/O Controller is a small form factor stand-alone device that supports two D.20 link channels for communication with the D20 series of input / output modules.

• Interface with standard D20 I/O (status, analog input, control and combination input) peripheral modules
• Support for up to 30 I/O modules in a single D.20 RIO, or distributed over up to four D.20 RIO devices within the substation
• Small form factor with multiple mounting options for installation flexibility: 19" Rack, panel mount or DIN Rail

Use the D.20 RIO module to install input / output modules in the substation LAN. No substation LAN? No problem, connect the optional D.20 RIO device directly to the built-in D400 Ethernet switch.

Front Panel 

Back Panel

The Multilin D20MX supports a comprehensive set of security functions to allow a seamless integration with existing IT department policies. Built-in cyber security features, such as Remote Authentication Dial-In User Service (RADIUS), Role Based Access Control (RBAC), and user activity logging, provide a complete security toolkit required to enable simpler and more efficient compliance with NERC-CIP requirements, using open and trusted standards and protocols, that allow integration with modern cyber security systems and tools.

Backwards Compatibility with Earlier Vintages of Multilin D20 RTUs

The Multilin D20MX is an embedded single board computer powered by a 667 MHz PowerQUICC II Pro processor pin-for-pin compatible unit with existing D20 Processors and accessories, such as chassis, D20 remote I/O peripherals, modems.

Fully Equipped Out-of-the-Box

Previous generations of D20/D200 RTUs required add-on system components and software to support Ethernet communications and optional memory expansion. The new D20MX is equipped by default with integrated memory, 10/100/1000BASE-TX or 100BASE-FX IEEE 802.3 compliant communications and a core load firmware with a comprehensive set of key substation automation applications.

A complete family of substation hardened I/O modules makes the D20MX controller scalable to both large and small substations. A distributed architecture with both ring and star topologies allows for easy expandability and remote placement of I/O modules. The following I/O modules are available in a variety of models with I/O ranges up to 300VDC.

I/O with DNP Communication

The DNP I/O modules are data collection and control devices that combine the DNP 3.0 communications protocol with our existing industry proven and robust line of I/O modules. The DNP I/O modules implement the industry standard DNP 3.0 (Level 2) slave protocol over a single RS485 interface to provide expandable I/O functionality for the D400, D25 and iBox product lines, as well as third-party products.
The following DNP I/O modules are available: