Increasing situational awareness of system operators by highly aggregated dynamic security results. Dr. Uros Kerin

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1 1 Increasing situational awareness of system operators by highly aggregated dynamic security results Dr. Uros Kerin

2 Introduction Renewables feeding all voltage levels Bulk wind farms onshore and offshore feeding transmission grid Smaller wind farms and large PV plants feeding distribution grid Small roof PV plants feeding LV grid Energy infeed is predictable, power infeed not Energy trade Energy market is deregulated Transmission system expansion Reduction of spinning reserve Power electronics equipments Reduction of system inertia High system dynamics Transmission grids with a clear Power Transmission task are transformed into Power Exchange platforms

Energy trade Energy market is deregulated Transmission system expansion Reduction of spinning reserve Power electronics equipments

3 Power system operator The power system operator s role is similar to one of the car driver or airplane pilot - a generation/ load schedule to follow; - operate under provision of grid code rules; - cope with planned/ unplanned outages and contingencies; - foresee and avoid dangerous situations.

follow; - operate under provision of grid code rules; - cope with

4 Power system operator The power system operator s role is similar to one of the car driver or airplane pilot - a generation/ load schedule to follow; - operate under provision of grid code rules; - cope with planned/ unplanned outages and contingencies; - foresee and avoid dangerous situations.

5 Control centers today Development of electric power systems Passive electric systems (transformers, generators transmission lines, mechanical breakers) Complex intelligent systems power electronics, fast digital and protecition systems IGBT based FACTS, MT- HVDC Distributed Generation Smart Grids Electric Vehicles Development of supervisory and control systems First SCADA systems SCADA/ EMS/ PMU + stability tools PMU SCADA / EMS systems for power systems

FACTS, MT- HVDC Distributed Generation Smart Grids Electric Vehicles Development of supervisory and control systems First

6 Dynamic security assessment limit t0 Time t1 Dynamic frequency excursions Dynamic loading of equipment Generator dynamic stability Low frequency oscillations Dynamic voltage excursions Protection settings and others

Generator dynamic stability Low frequency

7 Dynamic security assessment System State Dynamic Analysis Working point now forecasts time - Re-dispatch - tap-changer blocking - load shedding -... Measures Visualization

8 Security aspects Transformer loading Power line loading Node voltages Transformer Power Flow Index Line Power Flow Index Quasi-Stationary Voltage Index simulation and measurements simulation Max. loading of nodes and steady state voltage stability Generator synchronism Dynamic frequency excursions Dynamic voltage excursions Load shedding Transient Stability Voltage Stability Small Signal Stability Grid Code and Technical Limits Dynamic Security Indices Nodal loading index Thevenin Index Approximated Voltage Index Under-Over Voltage Index Angle Index Maximum Frequency Deviation Index Frequency Gradient Index Frequency Recovery Time Index Dynamic Voltage Index Voltage Ride through Index Load Shedding Index Energy Margin Index (relative distance to transient instability) Voltage Violation Index (Q-reserve, OLTC) Small Signal Security Index (mode frequency, damping)

Stability Grid Code and Technical Limits Dynamic Security Indices Nodal loading index Thevenin Index Approximated Voltage Index Under-Over Voltage Index Angle Index Maximum Frequency Deviation Index

9 Voltage ride through index é æ öù ê ç areaj D Vi dt ú ê ç ò ú tareaj VRTI = min ê1, max ç ú ê ç areaj A ú maxadm ê ç ú ê ç ú êë è øúû ì < areaj, if Vi Vmin adm areaj ï band areaj band i ív minadm i, if minadm< i Vminadm ï band 0,if Vi ³ Vminadm D V = - V V V< ïî A area j area j area j max adm = Vmin adm tmax adm Violation of Grid Code Limits

band areaj band i ív minadm i, if minadm< i Vminadm ï band 0,if Vi ³ Vminadm D V = -

10 Multi-stage soft-computing system Overall Power System Security 1.0 INSECURE c b a SECURE

11 Common platform SCADA Snapshot Steady-State Network Interface Energy Trade, Renewable and Load Forecast Dynamic Network Database SIGUARD PDP PMU Data Stream Dynamic PMU Interface Contingencies & Measures Scenarios Automatic Contingencies & Measures Protection Database SETUP, CONFIGURATION Margins & Criteria Index Selection U P Voltage Stability Computation Engine Small Signal Stability Margin Calculation Margin CalculationMargin Calculation Application Platform σ 5% Visualization & Reporting f Ranking d fault Transient Stability t PSS Suite Contingencies, Measures Interface Result Database SCADA SIGUARD PSA RDC SCADA SIGUARD PDP Monitoring

Selection U P Voltage Stability Computation Engine Small Signal Stability Margin Calculation Margin CalculationMargin Calculation Application Platform σ 5%

12 Interfacing and incorporation

13 Results post-contingency pre-contingency results distribution history current working point forecast

14 Summary and conclusion traditional operational concepts as such are becoming insufficient tools for increasing situational awareness of the operators are required real time DSA tools have to be adopted for the operators to prevent outages, (taskforce investigating 2003 US-Canada blackout, recommendation no. 22) conduct security assessment to assess contingency situations, (NERC, policy no. 9) key method for ensuring for reliable system operation is the use of online DSA tools, (CIGRE WG C4)...new tools for security assessment need to be developed, (ENTSO-E, R&D plan EUROGIRD 2020) in addition to, rather than instead of, well-established and proven concepts

22) conduct security assessment to assess contingency situations, (NERC, policy no.

Modern Power Systems for Smart Energy Society

Modern Power Systems for Smart Energy Society Zhe CHEN Professor, PhD Email: [email protected] Website: http://homes.et.aau.dk/zch http://www.et.aau.dk 1 Contents Energy background in Denmark Challenges to