Large Disturbance and System Security Defense Schemes Dr. Herman Darnel Ibrahim Chairman of Indonesian National Committee of CIGRE Lecturer of Power System Operation and Control Post Graduate Program University Indonesia MKI and IDNC CIGRE Joint Workshop Jakarta, 18 September 2019 Large Disturbance and Blackout ▪ Large Disturbance: Large Disturbance do occur on the system . These include severe lightning strikes; loss of transmission carrying bulk power, due to overloading; loss of a generating station; or loss of major load. [Vijay Vittal, Iowa State University: pserc.wisc.edu] ▪ Large Disturbance: Large Disturbance in power systems are us ually triggered by some initial fault and then spread over the system due to combined effect of many reasons such as malfunction of equipment, lack of appropriate information and human faults. [Stojsavljevic, Energy Institute, Croatia: bib.irb.hr] ▪ Blackout: A blackout is the total loss of power to an area , and is the most severe form of power outage that can occur. Blackouts which result from power station tripping are particularly difficult to recover quickly. [en.m.wikipedia.org]. Possible Causes of Large Disturbance ▪ Large Disturbance usually happen following system’s component fault. Component faults may cause : • Generation trip and deficit of generation • System in-stability • Line or transformer overloading ▪ Large Disturbance happen when defense scheme does not work properly. Possible Causes of Large Disturbance: • Abnormal trip of generation unit [Frequency> 47.5 Hertz] • In-adequate response of generation [dF/dt >>] • In-sufficient and in-appropriate Load Shedding • In-adequate Protection Systems • Protection system malfunction Highly Interconnected Power Grid and Large Disturbances ▪ Interconnection provide greater flexibility and reliability, and increase system strength [MW/ Hertz]. ▪ Simple system has higher risk of power outage [black out]. As it is small the effect is not severe, and recovery is quick. ▪ Highly interconnected system has lower risk of power outage. As it is big, it may experience Large Disturbances, the effect is severe, and recovery may take much longer. ▪ Smaller system in outside Java has higher risk of blackout than it is in Java Bali system. ▪ In the first month of my duty as Manager of South Sumatera Control Centre [February 1988], blackout almost happen every day but recovery was very quick. Large Disturbance Defense Scheme: Security "N - 1" System Remain Stable without: Load Curtailment, Transmission Overloading and Exceeding Power Transfer Stability Limit. “N – 1” : System Experience Any one of Component Outage System Has Adequate Generation Spinning Reserve Non of the Lines and Transformers Experience Overloading System Stability: Limit of Power Transfer Is Not Exceeded Large Disturbance Defense Scheme: Security “N – 2” System Remain Stable with Load Curtailment. Load Shedding Scheme should alleviate Transmission Overloading and Over Power Transfer of Stability Limit “N – 2” : System Experience 2 Simultaneous Component Outage System Stable with Load Curtailment and No Other Plant Trip After Load Curtailment Non of the Lines Experience Overloading After Load Shedding: Limit of Power Transfer Is Not Exceeded Large Disturbance Defense Scheme: Prevent Plant Trip and Adequate Hot Reserve System Should Have Adequate and Appropriate Spinning Reserve when experience “N - 1”: ▪ Following a Disturbance all plant should stay in operation [maintain No Power Station Trip]. Grid Code: Frequency Set 47.5 Hertz. ▪ Adequate amount of Spinning Reserve: greater than Larges Unit capacity. ▪ Generation with spinning reserve should be set governor free or with AGC scheme ▪ Generation with spinning reserve has fast response; adequate ramping rate [dP/dt] to withstand high dF/dt. ▪ Appropriate distribution or location of spinning reserve, so it can be evacuated without causing line overloading or system instability Large Disturbance Defense Scheme: Appropriate Load Shedding Scheme System Should Have Adequate and Appropriate Load Shedding Scheme: ▪ Load Shedding Scheme should be set to secure “N – 2” condition. ▪ For Large system, Load Shedding scheme [to secure the large disturbance] is not simple : it is about amount, location, frequency setting and speed. ▪ Load Shedding scheme should be reviewed and be reset following each time system changes. ▪ Modern system apply Smart Load Shedding Scheme executed and updated on line. ▪ Securing Large Fault [high generation deficit] requires Fast Load Shedding using “dF/dt” Relay for Larger Load. Large Disturbance Defense Scheme: Modern Energy Smart Load Shedding Change in operation condition, feeder flow, generation local capacity, transformers and feeder loads List of Initiator of Load Shedding Monitoring and Prediction of System Behaviour Load Shedding Optimizer Knowledge Base Utilizes carefully selected inputs and outputs, based on off line studies and models. Based on prior defined system disturbance; Include topologic information of connections and electrical properties of the components of the system System Disturbances Grid Models *Source: www.dicsintertrade.com Programmable controllers quickly perform load shedding based on the detection of initiator Distributed Control Programmabl e Controller Tables of calculated optimal load shedding , corresponding to system changes; Features: 1. Considering system dynamic response. 2. Load to be shed is dynamic and optimal to suit the system condition change 3. Faster than UFR Load Shedding Large Disturbance Defense Scheme: Pre-Set Islanding Scheme For Large System, Islanding Scheme is set to protect system from Total Blackout: ▪ Islanding Scheme is usually pre-set by Operation Planning expert. ▪ An Islanding Scheme is a subsystem contains balanced amount of demand [load] and generation capacity [similar to Smartgrid microgrid concept] ▪ A special protection scheme is set to isolate and form the preset island when condition requiring [during disturbance]. ▪ Islanding Scheme should be reviewed and updated to accommodate changes and to ensure it will work properly. Large Disturbance Defense Scheme: Maintain Power Transfer Stability Limit ▪ Power Transfer Stability Limit is defined by following formula: Pmax = [V1* V2/ X] SIN ∂ X G 2X V1 4X G V2 ▪ Maximum transfer with 2 lines operation is 0.5 Pmax , and with 1 line is 0.25 Pmax . ▪ Power transfer must be adjusted if number of lines in operation change. ▪ A Special Protection must be in place to re-adjust the power transfer automatically, when number of lines reduced. Large Disturbance Defense Scheme: Routine Check of N – 1 Contingency Plan ▪ System condition is dynamic, so that “N – 1” contingency plan is also dynamic. ▪ “N – 1” Contingency Analyses should be run every time network topology changes. Change of: • Network Topology • Generation • Load Contingency “N – 1” Simulation [Analyses] Load Flow: No Line Overloading Stability Limit Not Exceeded ▪ “N – 1” Contingency plan should always be checked for significant change of load and generation Large Disturbance Defense Scheme: Knowledgeable and Skilled Operator Operator and Operator Supervisor Have A Good Knowledge of System Security and High Skill to Take Necessary Action in Maintaining All System Security Defense Scheme: ▪ Operator should have a sound understanding about all system security defense scheme. ▪ Operator should have high level of knowledge on how to maintain system security. ▪ Operators or their Supervisor should run Security Analyses every time system experience change of topology. ▪ Operator should have high skill in taking action to alleviate system in-security. Defense Scheme Check List No Defense Scheme Requirement Remarks 1. Contingency N -1 System remain stable without load shedding. Must be checked if system change. 2. Contingency N-2 System remain stable with load shedding Check for Adequate Load Shedding 3. Adequate Spinning Reserve: for N -1 Adequate amount, set governor free, appropriate location Fast Response: High Ramping Rate dP/dt 4. Appropriate Load Shedding Securing N – 2. Right amount, right distribution, right speed Dynamic Setting: Smart Load Shedding 5. Pre Set Islanding Scheme Successful islanding following large disturbance and system split Design and Setting of Scheme 6. Maintain Stability Limit Power transfer must be readjusted if number of lines reduced Need special protection 7. Running N – 1 Security Analyses Routine running to check and fix the N – 1 security from time to time Software and Skill of Staff [Operator] 8. Operator Knowledge High level of knowledge and skill to + Skill maintain power system security Education and Training Status of Operation Condition Normal Recovery ▪ All loads is normally served ▪ Contingency Plan “N – 1” is satisfied Changes Changes Alert ▪ All loads is still served [No load curtailment] ▪ "N - 1" Contingency Plan is not satisfied Recovery Recovery Changes Emergency ▪ Disturbance Causing Load Curtailment ▪ "N - 1" Contingency Plan is not satisfied Blackout ▪ Severe power outage occur following disturbance ▪ Total loss of power in an area Changes Operation and Disturbance Experience: Southern Sumatera System 1988 I was the First Manager of Southern Sumatera Grid Control Centre: ▪ Computer Based Control Centre for Southern Sumatera System was first introduced [completed] in February 1988. ▪ At that time a relatively large Coal Steam Power Plant Bukit Asam 2 x 65 MW has just been completed and start its first year operation. [and still perform various Plant Test and Less Reliable]. ▪ Before that Southern Sumatra Power System had 4 power station with total capacity of 95 MW [ Small SPP, GTPP and DPP], serving the system peak load of 85 MW [day time 65 MW] through 15 Substations. ▪ System experienced disturbance [mainly due to Power Station trips] almost every day. Blackout Experience: Southern Sumatera System 1988 In the first month of the operation [March 1988] system experience 26 blackouts. Subsystem Palembang City: Bukit Asam and Outer Palembang Subsystem: • Peak Demand ~ 15 MW [day time ~ 10 MW • New SPP 2 x 65 MW and DPP ~10 MW • 6 Substation 150 kV lines Up to 65 MW Operation Condition: • Largest Unit > Day Time Peak. • New Units were under testing • Minimum Defense Scheme [No UFR, Hot Reserve < Largest Unit] • Lack of SOP and Communication Facility • • • Peak Demand ~ 70 MW [day time 55 MW] Generation 85 MW [SPP, GTPP and DPP] 9 Substation Handling and Improvement: • Mostly we knew there will be blackout • Quick Recovery ~ 30 minutes maximum 45 minutes. • Installed UFR • Improve SOP and Communication Example of Large Disturbance: Java Bali Western-Eastern System Split West Java Jakarta and Banten System: ~11000 MW Load, Importing Power from East Mandirancan Substation Short after 11.45 both 500 kV lines TasikmalayaDepok Trip causing system split Western and Eastern Tasikmalaya Substation 500 kV North lines UngaranMandirancan [Cirebon] At 11 45 , line fault causing both line tripped. 2300 Megawatt 500 kV South Lines Pedan Tasikmalaya 1 line maintenance outage Central Eastern Java System: Exporting Power to the West Java Bali Large Disturbance: Western System, After System Split Other Island Scheme Jakarta Island Scheme Other Island Scheme Other Island Scheme Western System Emergency State: Load ~ 11.000 MW Generation ~ 10.000 MW Loss of Supply [from East] ~2.000 MW System Response: Load Shedding ~ 1000 MW Generation Response ~ 800 Eastern System Experience Over Supply, Frequency Increase Final State : System Stable Western System Strength ~ 500 MW/ Hertz, dF/dt ~ High, frequency may drop more then 3 Hertz Security Defense : Generation Response Load Shedding V V...? Islanding Scheme ? No Power Station Trip ? High Speed “dF/dt” ? BLACKOUT hardly occur in highly interconnected system. It can be prevented through Defense Schemes. Its risks of happening can be reduced but CAN NOT BE AVOIDED, as there is no 100% reliability. World Blackouts 2018 Blackouts 2019 Blackouts Year Blackouts 07 Mar Venezuela 10 Jan Sudan 25 Mar Venezuela 21 Jan Sudan 2000-2009 48 09 Jun Texas 27 Jan Sudan 2010 9 16 Jun Argentina 02 Mar US East Coast 2011 13 19 Jul Wisconsin 21 Mar Brazil 2012 6 19 Jul Michigan 12 Apr Puerto Rico 22 Jul New Jersey 03 Jul Azerbaijan 2013 10 04 Aug Indonesia 06 Sep Hokkaido 2014 9 09 Aug England 21 Sep Ottawa 2015 8 01 Sep Bahamas 10 Oct Florida 2016 4 15 Oct Venezuela 2017 11 15 Nov Sulawesi Past 10 years : 94 Blackouts 04 Dec Saskatchewan 2018 14 Blackouts 2018 14 20 Dec Vancouver 2019 §0 Blackouts 2019 10 *Source: List of Major Power Outages: en.wikipedia.org Blackout Happen Every Where India London UK Italy New York Jakarta London Underground Brazil Argentina Paraguay Japan Venezuela 2019.09.18 by HDI MKI CIGRE Workshop 21 Closing Remarks ▪ BLACKOUT hardly occur in highly interconnected system. It can be prevented through Defense Schemes. The risk of its happening can be reduced but CAN NOT BE AVOIDED, as there is no 100% reliability. ▪ SECURITY is the MOST IMPORTANT aspect of operation, it is not free, it has cost. Blackout costs us more than loss of electricity, it cost loss of income for customers, and costs reputation for the utility. ▪ To minimized the risks of blackout, UTILITY should INVEST in MODERN HARDWARE and SOFTWARE to put the required Defense Scheme and SCADATEL infrastructures in place. ▪ UTILITY should also INVEST for continuous improvement of BRAINWARE and SKILL of its Managers, Engineers and Operators. Recruit and retain Best and Smart personnel. ▪ It is a common practice in all utilities to do their BEST in preventing Large Disturbance. However it happen un-intentionally every where. Stakeholders and society should ACCEPT it as an ACCIDENT. Biography of Herman Darnel Ibrahim Chairman of CIGRE [International Council of Large Electric Systems] Indonesian National Committee Born in 1954. He is a Member of House of Regional Representative [Senator] and was Board Member of DEN, the National Energy Council of Indonesia 2009-2014 and Former Director of PLN the State Electricity Corporation [2003-2008]. Beside he serves as Freelance Consultant, Chair of ICEES [Indonesian Counterpart for Energy and Environmental Solutions], a GLG Group Council Member, a Lecturer at Faculty of Engineering of University Indonesia, and Advisor in energy companies. He also serves as Member of Board of Supervisors of Indonesian Renewable Energy Society [IRES], Vice Chair of Expert Board of Indonesian Energy Conservation and Energy Efficiency Society [MASKEEI], Member of Expert Board of Indonesian Power Society [MKI], Advisory Board Member of Indonesia Geothermal Association [INAGA], and Indonesia Ocean Energy Association [INOCEAN]. He is also active in International Organization, as Chairman of Indonesian National Committee of CIGRE [International Council of Large Electric Systems] since 2006, and as Vice President IGA, International Geothermal Association [2013-2016]. Herman got his First Degree in Electrical Engineering from Bandung Institute of Technology [ITB]; M.Sc. Degree in Electrical Power System Analysis from the University of Manchester, UK; and Doctor Degree in Technical Science from ITB Bandung with research topic the Energy Policy for Power System Development. For 30 years until 2008, he worked with PLN, the State Electricity Corporation of Indonesia. He achieved senior management position at the company as Director Transmission and Distribution [2003-2008], Director of PT. Indonesia Power, a subsidiary of PLN [1998-2003]. He wrote several papers, public media articles and a book titled Energi Selamatkan Negeri [Energy to Safe the Country]. In the past decade he contributed as the Speaker and Panelist at several national and international energy conferences. Vientiane 18.05.23 by HDI ASEAN Power Grid 23 Terima Kasih Thank You 2019.09.18 by HDI MKI CIGRE Workshop 24