Distribution Operations - Overview of Advanced Distribution Automation

Introduction to Advanced Distribution Automation (ADA)

Objective: The objective of Advanced Distribution Automation Function is to enhance the reliability of power system service, power quality, and power system efficiency, by automating the following three processes of distribution operation control: data preparation in near-real-time; optimal decision-making; and the control of distribution operations in coordination with transmission and generation systems operations.

Scope: The ADA Function performs a) data gathering, along with data consistency checking and correcting; b) integrity checking of the distribution power system model; c) periodic and event-driven system modeling and analysis; d) current and predictive alarming; e) contingency analysis; f) coordinated volt/var optimization: g) fault location, isolation, and service restoration; h) multi-level feeder reconfiguration; i) pre-arming of RAS and coordination of emergency actions in distribution; j) pre-arming of restoration schemes and coordination of restorative actions in distribution, and k) logging and reporting. These processes are performed through direct interfaces with different databases and systems, (EMS, OMS, CIS, MOS, SCADA, AM/FM/GIS, AMS and WMS), comprehensive near real-time simulations of operating conditions, near real-time predictive optimization, and actual real-time control of distribution operations.

Rationale: By meeting its objectives in near-real time, the Function makes a significant contribution to improving the power system operations through automation, which cannot be achieved using existing operational methods.

Status: The methodology and specification of the Function for current power system conditions have been developed, and prototype (pilot) and system-wide project in several North-American utilities have been implemented by Utility Consulting International and its client utilities prior to IntelliGrid Architecture project.

Figure 1: Coordination of ADA applications is accomplished through internal interfaces within the ADA function and through the feedback from the power system

Figure 2: Real-Time Distribution Operations showing Interactions and Information Flows

Figure 3: What Do We Need to Know to Optimally Control Distribution?

Figure 4: Information Flows within Advanced Distribution Automation (ADA)

Additional Information

Contractual Relationships

*Contract/Regulation*	*Impact of Contract/Regulation on Function*
Contract between DISCO and TRANSCO	Operational boundaries. If the boundaries are at the circuit breaker level, then ADA has no direct access to substation capacitors and voltage regulators within the substation fence. In order to execute coordinated Volt/Var control, feeder reconfiguration, service restoration, ADA needs information about the substation connectivity, substation transformer loading, state of voltage regulators and capacitors, and their controllers. Furthermore, ADA should have capabilities for controlling these devices in a closed-loop mode. If the boundaries are at the high-voltage side of the substation transformer, then ADA has access to the substation devices and corresponding information. Volt/Var Agreement. Defines the voltage limits at the transmission side and reactive power requirements for distribution side. If the contractual parameters are not respected, the Volt/Var application may not meet its objectives, and the voltage limits at the customer side may be violated.
Contracts between DISCO and DER owners	Schedules. Defines amount of kW generated by DER at different times and constraints for power flow at Point of Common Coupling (PCC). Deviation from schedules must be timely detected and compensated by other reserve capabilities of the distribution system. Volt/Var control agreement. Defines modes of DER operation and setting for Volt/Var control. Defines rules for changes of modes of operation and setting (local/remote, DER/EPS). Deviation from agreement must be timely detected and compensated by other reserve capabilities of the distribution system. Standard 1547. Defines rules for interconnection between DER and DISCO (EPS). Deviation from the rules may result in violation of power quality limits, delays in service restoration, damage of DER equipment. Deviation from the standard must be timely detected and remedial actions must be implemented.
Contracts between Disco and Customers	Standard 519. Defines power quality requirements at customer terminals. ADA functions are designed to respect these requirements. ADA must be capable of monitoring or accurately estimating the power quality parameters at the customer terminals, report and eliminate (or significantly reduce) the violations. Performance based rates. Defines the target level of service reliability. The distribution system and the ADA function should be design to meet the target. Reliability guarantees. ADA function should distinguish the customers with reliability guarantees from those without and focus the service restoration solution on meeting the guarantees, while providing other customers with target service reliability. Load management agreements. Defines the conditions, amount, and frequency of direct load control, load curtailment, interruption, and shedding.

Actor (Stakeholder) Roles

*Grouping (Community)*		*Group Description*
*Actor Name*	*Actor Type*	*Actor Description*
DisCos Operator		Person in charge of distribution operations during the shift
Distribution SCADA System		Distribution System Supervisory Control and Data Acquisition
Conversion Validation Function		The C&V function uses standard interface between AM_FM_GIS Database and converts and validates information about incremental changes implemented in the field.
ADA Data Checker		The ADA Data Checker monitors data entered into SCADA database and detects changes. When pre-defined changes are detected, the data checker triggers the ADA Dispatching System.
ADA Dispatching System		The ADA Dispatching System starts corresponding ADA functions based on pre-defined periodicity and events detected by the ADA Data Checker.
ADA Topology Update System		The ADA Topology Update System updates the ADA topology model based on status changes detected by the data checker
ADA Distribution Operation Model and Analysis (DOMA)		Calculation and Analysis of power flow/state estimation results
ADA VVC Controller (VVC)		ADA Voltage and Var Controller: Coordinated optimal control of voltage and var in distribution for different system-wide objectives
ADA: Fault location function		Fault detection and location in distribution
ADA: Fault Isolation and Service Restoration (FLIR)		Isolation of faulted portions of distribution feeders and restoration of services to healthy portions
ADA: Feeder Reconfiguration (FR)		Optimal selection of feeder connectivity for different objectives
ADA: Relay protection coordination		Adjustment of relay protection settings and operational modes of switches to provide a coordinated relay protection under real-time configuration
ADA: Prearming of Remedial Action Schemes (RAS)		Change of RAS settings in anticipation of a probable emergency
ADA Emergency Coordination System		Change of action priorities during the emergency state of the system
ADA Restoration Coordination System		Controlling the priorities of actions during the restorative state of the system
ADA: Intelligent Alarm Processing		Summarizing multiple alarms into one descriptive message.
Load Management Device		Controlling cycles of cyclic electric appliances (direct load control-DLC), interruptible and curtailable loads
UFLS: Under-Frequency Load Shedding Schemes		Shedding load based on frequency conditions
UVLS: Under-Voltage Load Shedding Schemes		Shedding load based on voltage conditions
SLS: Special Load Shedding Schemes		Shedding load based on specific operating conditions
Outage Management System		Trouble call processing, troubleshoot crew dispatch
Work Management System		Maintenance management in distribution
Field Personnel		Manual operations of field devices, repair and construction work
Field Device		Local intelligence for monitoring and control of automated devices in distribution, communicates with SCADA
Distributed Intelligence Schemes		Distributed Intelligence Schemes (DIS) - Performs operations in a localized distribution area based on local information and on data exchange between members of the group. Can communicate with SCADA.
IEDs of DIS members		IEDs grouped in a Distributed Intelligence Scheme
DER Owner		Maintenance and operations of DERs
TransCos		Transmission of energy from generation to distribution within distribution-defined constraints/contracts
Energy Management System		Transmission and generation management system providing ADA with transmission/generation-related objectives, constraints, and input data
RTO/ISO		Wide-area power system control center providing high-level load management and other signals for DisCos
Market Operation System		Wide-area energy market management system providing high-level market signals for DisCos
Major customers		Major users of DisCo’s services according to regulatory and contract rules
Customer Service Representative		Intermediary entity between DisCos and group of customers
AM_FM_GIS Database		Repository of distribution system assets, their relationships (connectivity), ownerships, and activities
Customer Information System		Repository of customer information related to DisCos services
Automated Meter Reading Device		Automated Meter Reading interfaced with CIS and AM_FM_GIS Databases
Asset Management System		Asset Management Systems interfaced with AM/FM/GIS
Remedial Action Scheme		Remedial Action Scheme performs local emergency operations based on local information, pre-armed settings and external signals. Can adapt to the changing local operating conditions.
ADA Database		ADA Database contains information on the current connectivity, operational parameters, electrical, economic and other relevant characteristics of the distribution power system
ADA Historic Database
ADA Test Database
Environmental daily data collector
IT Personnel
Load Forecaster
DMS SCADA Database
System Operator
Prearming of RAS schemes function
Fault isolation and service restoration subfunction
ADA load management functions		Including ADA VVC Controller

Information exchanged

*Information Object Name*	*Information Object Description*
See individual steps
AM_FM_GIS Databases	Nominal connectivity, electrical parameters, and geographic locations of distribution and transmission facilities
CIS database	Customer information including billing data, customer types, links to distribution circuits
Outage management system	Trouble call information, crew activity information.
DMS/SCADA database	Real-time data from field IEDs and output of ADA applications
Energy Management System/SCADA	Real-time data from transmission field IEDs, output from Energy Management System applications, information support from ADA applications
Engineering databases	Planning and design data for future facilities

Activities/Services

*Activity/Service Name*	*Activities/Services Provided*
DOMA: ADA updates power system model and analyzes distribution operations	· Update of a) topology model b) facilities model c) load model d) relevant transmission model · Analysis of real-time operating conditions using distribution power flow/state estimation · Evaluation of system transfer capacity based on real-time measurements · Issue of alarming/warning messages to the operator · Generation of distribution operation reports and logs
FLIR: ADA performs fault location, fault isolation, and service restoration	· ADA indicates faults cleared by controllable protective devices by distinguishing between: a) faults cleared by fuses b) momentary outages c) inrush/cold load current · ADA determines the faulted sections based on SCADA fault indications and protection lockout signals · ADA estimates the probable fault locations based on SCADA fault current measurements and real-time fault analysis · ADA determines the fault-clearing non-monitored protective device based on trouble call inputs and dynamic connectivity model · ADA generates switching orders for fault isolation, service restoration, and return to normal (taking into account the availability of remotely controlled switching devices, feeder paralleling, and cold-load pickup): a) SystemOperator executes switching orders by using SCADA b) SystemOperator authorizes ADA application to execute switching orders in closed-loop mode · ADA isolates the fault and restores service automatically by-passing the operator based on operator’s authorization in advance · ADA pre-arms Distributed Intelligence schemes · ADA considers creation of islands supported by distributed resources for service restoration
MFR: ADA performs multi-level feeder reconfiguration for different objectives	Service restoration Overload elimination Loss minimization Voltage balancing Reliability improvement
RPR: ADA performs relay protection re-coordination	· ADA changes relay protection settings and modes of operation of switching devices after feeder reconfiguration · ADA changes relay protection setting in case of changed conditions for fuse saving
VVC: ADA optimally controls volt/var by changing the states of voltage controllers, shunts, and distributed resources in a coordinated manner for different objectives under normal and emergency conditions	· Power quality improvement · Overload elimination/reduction · Load management · Transmission operation support in accordance with T&D contracts · Loss minimization in distribution and transmission
CEA: Protection equipment performs system protection actions under emergency conditions	Based on real-time distribution system connectivity, current composition of customers, and signals from an upper level of control, ADA provides protection system with information needed for properly performing under-frequency and under-voltage load shedding.
IAP: Intelligent alarm processing	Alarms, measurements, and messages produced by SCADA and ADA are processed by IAP to determine the root cause of the problem and deliver the summary message to the appropriate recipients of this information.
SCADA: system performs disturbance monitoring	· Fault current recording · Fault location · Event recording · Disturbance analysis
Op Dispatch