The IT Architecture and Applications for the TSO Back-up Control Center

M. Stojić, G. Jakupović, N. Čukalevski"Mihajlo Pupin Institute", Belgrade, Serbia

• First basic EMS system in Serbian NCC started in 2004 (developed in MPI)

• In 2007 Areva SCADA/EMS system started, MPI system kept as secondary started, MPI system kept as secondary working in parallel

• Decision to upgrade old MPI system for possible use in Serbian Backup NCC

Old MPI EMS Network Applications

• Application Data Base (ADB)• Network Topology Processor (NT)• State Estimator (SE)• State Estimator (SE)• Bus Load Forecast (BLF)

NEW MPI EMSNew Applications/Major Changes:

• Dispatcher Load Flow (DLF)• Contigency Analisys (CA)• Import/Export in standard format (UCTE.DEF orCIM/XML)

• Network Topology Processor (problems with maintenance and implementation of imp./exp.)

• Application Database• User Interface• Various interfaces etc.

Basic Organization of SCADA/EMS Network Applications

Software Modules 1

• SCADA• SCADA API (Application Programming Interface)• SCADA - ADB Data Exchanger retrieves SCADA data

(measurements and statuses) and writes them into ADB. It also writes estimated data into SCADA run-time segments for displaying purposes.segments for displaying purposes.

• Application for database format conversion (abp_import)• Application which prepares input data for topology

processor (abp2nt). This application is used in study mode only, on EMS workstation, on the user request.

• Application for UCTE.DEF and CIM/XML data import (ucte_import).

• Application that performs cyclic real-time operation (abp2nt_rt)

Software Modules 2

• Application database editor performs static topology modeling and power equipment parameters entry into ADB.

• EMS user interface (many components)• Network Topology Processor (NT)• Network Topology Processor (NT)• State Estimator (SE) • Bus Load Forecast (BLF) • Security Functions: Dispatcher Load Flow (DLF) & Contigency Analysis(CA)

NEW SOFTWARE MODULES

SCADA - ADB Data Exchanger

• In preset cycles reads necessary measurements and statuses from SCADA run-time segments and writes them into ADB. and writes them into ADB.

• Reads latest set of estimated values and writes them into SCADA shared segments for presentation on SCADA one-line diagrams and for use by other applications.

• Executes on SCADA servers.

NEW SOFTWARE MODULES

UCTE.DEF & CIM/XML Data Import

• Imported data are written into dynamically created and populated instance of ADB. Missing data (mainly in UCTE files) are Missing data (mainly in UCTE files) are replaced with default values.

• When ADB is populated from UCTE files, virtual circuit breakers are inserted in all branches for use in possible future study analyses.

NEW SOFTWARE MODULES

Database Format Conversion

• Application performs conversion from database format used by older versions of MPI EMS software into the new format.

• Difficulty in conversion due to the non • Difficulty in conversion due to the non existence of topological nodes in previous model.

• Automatically remodels topology and generates list of nodes.

NEW SOFTWARE MODULES

Database Editor

NEW SOFTWARE MODULES

EMS User Interface

NEW SOFTWARE MODULES

Network Topology Processor 1

• Determines network topology based on telemetered switching equipment statuses, static connectivities and model parameters. Creates bus branch network model with associated measurements.

• In previous OO design the whole system was described as connection of various equipment described ad multipolar objects but without explicit introduction of node entity. New design has without explicit introduction of node entity. New design has traditional bus-branch approach (more compatible with data exchange requirements).

• First phase In topology processing creates electrical buses by connecting nodes through processing of switching equipment statuses.

• In second topology processing stage bus-branch network equivalent model is created as an ordered set of buses connected with branches (lines or transformers). Electrical islands are identified in case of parttioned network.

NEW SOFTWARE MODULES

Network Topology Processor 2

• All equipment is modeled with Y equivalents allowing modeling of phase shifting transformers.

• Measurements allocation to bus-branch • Measurements allocation to bus-branch network equivalent model. Voltage measurements with large deviations are optionally removed.

• Determination of energized electrical islands

NEW SOFTWARE MODULES

Network Topology Processor 3

Gross errors detection in measurements and topology:

• Large deviations in voltage measurements at same bus. Outliers are optionally removed.

• Power flows on disconnected branches• Power flows on disconnected branches• Large disparity of power flows at different ends on a same branch

• Violation of First Kirchoff's law for power flows entering a bus

• Groundings in energized network portion• Power generations out of limits

NEW SOFTWARE MODULES

SECURITY FUNCTIONS

• Dispatcher Load Flow(DLF)– Standard full Newton-Raphson algorithm.– Security of control operations are assessed by AC Power Flow calculation performed on edited network model imported from base case. model imported from base case.

• Contingency Analysis(CA)– Calculates power flows for a list of contingencies applied to basecase. Every contingency is checked for voltage or current violations.

– Contingencies are defined in graphical user interface. May be any combination of transmission network equipment outage.

NEW SOFTWARE MODULES

SECURITY FUNCTIONS

• Basecase is stored as an instance in ADB. It is taken in real time or from historic archives. Consists of network model, bus voltages and power injections. GUI edited.

• Real time estimated voltages and power injections must be inserted back into ADB where treated as measurements. measurements.

• Prerequisite for both DLF and CA is whole system observability.

• Multiple electrical islands are allowed.• NT is always started before security functions taking into

account topological changes imposed by analyzed operator actions.

• NT determines load flow bus types (balance, PV, PQ…)

Reports Generation

CONCLUSION

System is upgraded for two reasons: • To enable new functionalities like security functions or import/export in standard data exchange formats (UCTE.DEF or exchange formats (UCTE.DEF or CIM/XML).

• Necessity of easier software and data maintenance.

Thank you for your attention!Thank you for your attention!

NOVI PROGRAMSKI MODULI

• Aplikacija koja ciklično izvršava „real-time“ sekvencu estimacije