TEPCO's operational technologies to prevent cascading outage

Transcription

1 1 CIGRE TNC Technical Seminar Future Renewable Energy and Smart Grid Technologies TEPCO's operational technologies to prevent cascading outage Shinichi Imai, P.E. THE Power Grid Solution, Inc. June 20, 2014

2 Preface 2 1. THE Power Grid Solution, Who We Are? 2. TEPCO s Actions against Traditional Stability Problems Voltage & Reactive Management Observations and Recommendations on 2003 US Blackout Adaptive UFLS operation in 311 earthquake 3. Renewable Integrations 4. Summary

3 Challenge Transition & Future Expectation 3 Challenge From Traditional Instability To Renewable Integration and Uncertainty From Post Actions To Preventive Actions Corrective Action Response Based P&C Scheme System Wide Optimization

4 Preface 4 1. THE Power Grid Solution, Who We Are? TEPCO Overview Japanese Power Industry Reform THE Approach 2. TEPCO s Actions against Traditional Stability Problems Voltage & Reactive Management Observations and Recommendations on 2003 US Blackout Adaptive UFLS operation in 311 earthquake 3. Renewable Integrations

5 Overview of Tokyo Electric Power Co. One of 10 vertically integrated utility Electricity sales; 269B kwh, 53.7B USD (100 JPY=1 USD) Area; 39,512 km2, Population; 44.8 M, Contracts; 28.9 M Generation Asset Hydro; 9.5GW/164 plants, Thermal; 41.6GW/25 plants, Nuclear; 14GW/3 plants, Renewable; 34MW/5 plants Transmission Asset OH; 14,751km circuit length, 51.2K towers UG; 6,387km circuit length Substation; 1,582 (74 over 275kV) 5

6 EHV Network Surrounding Metropolitan Tokyo 6 500kV UG 275kV UG 500kV OH Tokyo 23wards 275kV OH

7 Japanese power industry reform 7 Purpose Energy Security Promote energy exchange between utilities Diversify power resources by utilizing RES, DER Energy saving Affordability Competition among energy providers Opportunity Consumer can select any providers, which promote business chances and innovation Schedule Independent organization for wide area NW operation from 2015 Full liberalization of retail market from 2016 Legal structural separation of T&D from 2018 to 2020

8 Future industry organization 8 Now since 2003 Now since 2016 Gen Gen Gen Co T&D Utility T&D T&D Co Retail Retail Energy Service Provider All consumers Regulated Customer Non Regulated Customer

9 Mission and goal as T&D service provider of future Utility management reform in progress in TEPCO since April 2013 Fuel and Power Company, Power Grid Company, Customer Service Company Fairness, Neutrality, Transparency 9

10 THE, Who We Are? 10 Hitachi IT System Integration System Solution Technologies Utility Planning Knowledge Based O&M A new company of consulting and engineering in transmission & distribution, heat supply, and energy efficiency solutions Integrate Hitachi's system solutions technology with TEPCO s expertise

11 THE Approach 11 Hitachi - Technologies - Equipment - Solutions & Services TEPCO - O & M Experience - Knowledge/ Education Investment / Resource Investment / Resource THE - Develop Strategy - Marketing - Hands on/go2 market Partners - Utilities - Technologies - Service Providers Applied Locally Utilities Adaptions & enhancements to meet local operational constraints & challenges Government - Regulations - Rules - Economics Investment / Resource Support Feedback For Japanese Market (e.g. utility, regulation)

12 Preface THE Power Grid Solution, Who We Are? 2. TEPCO s Actions against Traditional Stability Problems Voltage & Reactive Management Observations and Recommendations on 2003 US Blackout Adaptive UFLS operation in 311 earthquake 3. Renewable Integrations 4. Summary

13 1987 Tokyo Voltage Collapse 13 July 23, 1987 Interrupted Power; 8.17 GW (Total Demand; 39.3GW) Duration; 3.35 hours Interrupted Customer; 2.8 million TX Line Tripped; 500kV- 3 circuits, 275kV- 4 circuits Transfomer Tripped; 4 Banks (275/66kV) Major Generator Emergency Stopped; 1.78 GW

14 Total Load Load Curve during Voltage Collapse 14 [GW] 39.3GW (13:10) 39 July 23, MW/min Voltage Collapse(13:19) MW/min Sept. 4, 1986 (The day of the maximum load in the previous year) 8,170MW Load Lost 35 12:50 13:00 13:10 13:20 13:30

15 Affected Area by Voltage Collapse 15 Kashiwazaki-Kariwa Nuclear Power Plant Fukushima Nuclear Power Plant 7GW 60Hz 50Hz FC Shin-Tama Shin-Hadano Shin-Fuji 60Hz FC 50Hz 500kV Overhead 275kV Overhead 275kV Underground Substation Affected Area

16 Reactance [ohm] Voltage Collapse Caused Zone 4 Distance Relay Operation Zone 4 Impedance Relay Setting at Shin-Tama :19 13:15 13: Resistance [ohm]

17 Frequency Excursion during Voltage Collapse 17 14:00 13: Hz 13:00 12: Frequency [Hz] System wide voltage decay caused over frequency due to voltage sensitive load characteristics Unintentional loss of load by distance relay operation forced voltage & frequency back to normal

18 500-kV Bus Voltage [kv] P-V Analysis :00 13:02 13:03 13: More Shunt Capacitors in Service 0.4GW Moving on the lower side of the P-V curves : System Demand [GW]

19 Shunt Capacitors [Gvar] Corrective Actions Setting to Keep a High Voltage Profile Shunt Capacitors Dynamic Reactive Reserves(SVC, Synchronous Condenser) Undervoltage Load Shedding Online Voltage Security Monitoring System For 5 years, 11.9 GVar 18.2G Var Year

20 Reactive Power Supply after Contingency 20 AVR AVR AVR AVR PSVR PSVR PSVR PSVR Increase Var Output in response to Voltage drop caused by Line Outage OFF OFF In a few seconds Reduce Var Output following automatic shunt capacitor switching OFF OFF VQC VQC Caps. Caps. Caps. Caps. ON ON Caps. Caps. Caps. Caps.

21 Undervoltage Load Shedding Microprocessor-based relaying scheme Voltage collapse is detected by central units located in the 500kV network, because 275kV or lower voltage are regulated by tap changing based on 3 out of 4 decision making logic to avoid unwanted operation CU 27kV,154kV radial network 500kV Main Grid Communication; Measured 500kV voltages CU CU Communication; Voltage collapse detection result RTU CU Sub-Station 275,154/66 21 Central units detect Voltage Drop (Under Voltage) Rate of Voltage drop (dv/dt) Unit) RTU Sub-Station 275,154/66 (CU: Central

22 Preface THE Power Grid Solution, Who We Are? 2. TEPCO s Actions against Traditional Stability Problems Voltage & Reactive Management Observations and Recommendations on 2003 US Canada Power Outage Adaptive UFLS operation in 311 earthquake 3. Renewable Integrations 4. Summary

23 What Happened in Initial Stage of Cascading 23

24 Eastlake Unit 5 Tripped by Overloaded MVAr Output 24

25 Zone-3 Distance Relay Caused Unwanted Tripping of Critical 345kV Line 25

26 n-8 Contingency Caused Voltage Collapse 26

27 Difficult to Stop Cascading 27

28 Recommendations improved voltage & reactive management 28 The situation of insufficient reactive power reserves causing poor power factor at generators should be improved by addition of shunt capacitor banks to transmission level. Dynamic reactive power reserves can be kept at generators. Voltage profile should be kept flat to the extent possible, in combination with sending end with generators and receiving end with shunt capacitor/reactor banks. Switched shunts rather than SVC/STATCOM could be reasonable solution.

29 29 Main Grid Power flow more than SIL Load center with sufficient generators Load center w/o sufficient generators Generators as dynamic reactive resources Shunt caps for load pf correction in distribution level Shunt caps to keep reactive reserves at generators in transmission level Poor Generations IM High percentage of motor loads Shunt caps to keep reactive reserves at generators in transmission level Fast shunt switching required for short-term instability. SVC/STATCOM might be, but justification using dynamic simulation would be necessary.

30 Preface THE Power Grid Solution, Who We Are? 2. TEPCO s Actions against Traditional Stability Problems Voltage & Reactive Management Observations and Recommendations on 2003 US Blackout Adaptive UFLS operation in 311 earthquake 3. Renewable Integrations 4. Summary

31 2-1. 3/11 Earthquake and Tsunami Mar/11/2011, massive quake and tsunami damaged lots of power plants (total 25GW+) and transmission/distribution systems, which caused wide range blackout in Tohoku and Kanto area. 3/11 quake: Center point and intensity of each area Tsunami Damaged transmission tower Damaged substation Damaged distribution line Source: METI website. 31 Copy Right Hitachi, Ltd All rights reserved.

32 32

33 7.1 GW Gen Loss Caused Severe Frequency Drop 5.7 GW Load Shed by UFLS saved Blackout 33

34 Adaptive UFLS 34 Level with Timer Settings Time Delay Shed loads 0.2s 8% 0.3s 4% s 4% (58.2) 0.7s 4% 56% 1.1s 4% Hz 48.0 (57.6) Hz 10.0s 4% 0.2s 8% 0.3s 8% 0.4s 8% 0.6s 8% 0.8s 8% 1.6s 8% 3.2s 8% 56% ROCOF ROCOF settings 49.0 (58.8) Hz 48.5 (58.2) Hz 49.0 (58.8) Hz 48.0 (57.6) Hz Shed loads 2.0s 12% 1.6s 16% 1.2s 20% 0.9s 24% 0.6s 28% 0.5s 32% 1.3s 4% 0.9s 8% 0.6s 12% 0.5s 16% 0.4s 20% 0.3s 24% 56% Combination of U/F with Timer and Rate Of Change Of Frequency Faster Frequency Decay Initiate More Load Shedding

35 2-2. Resiliency and Robustness Despite of the severe damages on power system, power outage recovered rapidly from right after the quake thanks to power utilities hard work. It showed how resilient and robust Japan s power system is. Exact and detailed outage information was available on real time basis, which helped the rescue and disaster recovery activity. 10,000,000 9,000,000 8,000,000 7,000,000 6,000,000 5,000,000 4,000,000 3,000,000 2,000,000 1,000,000 0 Mar/11 8,685,918 2,598,738 Mar/13 Number of houses / consumers of blackout in Tohoku and Kanto area 1,525, , , ,920 Mar/15 Mar/17 Mar/19 Mar/21 220, , , , , ,650 Mar/23 Mar/25 Mar/27 Source: Tohoku Electric Power Company s website and Tokyo Electric Power Company s website Mar/29 Mar/31 Apr/02 Apr/04 Apr/06 Apr/08 Apr/10 Apr/12 Apr/14 Apr/16 Apr/18 Apr/20 Apr/22 Apr/24 Shizuoka Yamanashi Ibaraki Gunma Saitama Chiba Tochigi Kanagawa Tokyo Yamagata Akita Aomori Miyagi Iwate Fukushima Tohoku Total Total 35 Copy Right Hitachi, Ltd All rights reserved.

36 Preface THE Power Grid Solution, Who We Are? 2. TEPCO s Actions against Traditional Stability Problems Voltage & Reactive Management Observations and Recommendations on 2003 US Blackout Adaptive UFLS operation in 311 earthquake 3. Renewable Integration 4. Summary

37 Grid Code; Gen Capacity, Reverse Power 37 Connected to Generator Capacity/Provider Reverse Power Low Voltage Inverter < 50 kw OK AC Gen Prohibited Medium Voltage Inverter or AC < 2,000 kw OK Spot Network Gen < 10,000 kw Prohibited High Voltage < 2,000 kw OK

38 Fault Ride Through Requirements for PV 38 Single Phase Continue to Operate Three Phase Voltage Voltage Operate OR Before March 2017 Gate Block Between April 2014 and March % 20% 1 sec After April sec Duration Duration Voltage Voltage 30% 20% 0.3 sec After April sec Duration Duration Due to cost and land constraints for Inverter, FRT requirements for large PV are eased.

39 Fault Ride Through Requirements for Wind 39 Three Phase PV Continue to Operate Wind, Three Phase, Over 20kW Between April 2014 and March 2017 Voltage Voltage 0.3 sec 30% Duration After April sec 20% Duration Operate OR Gate Block Voltage 90% 0% 0.15 sec 1.5 sec Duration PV (20%,0.3 秒 ) Wind Requirements Determined by Referring to German Requirements

40 Interconnected Capacity Limit for Wind Generator 40 Utility Limit (MW) Existing(MW) (Ratio of Limit) Dec, 07 Oct, 10 July, 12 Hokkaido (80.3%) Tohoku 850 1,180 1, (43.1%) Including 30MW with Energy Storage Tokyo No Limit No Limit No Limit 349 Ex. Of Analysis for Tohoku {Short Term(5 min) Regulation Limit= 880MW} OR {Long Term(20 min) Regulation Limit=850MW} = 850MW Energy Storage with Regulation Boost 330MW for Limit Total Limit = 850MW+330MW=1180

41 Preface THE Power Grid Solution, Who We Are? 2. TEPCO s Actions against Traditional Stability Problems Voltage & Reactive Management Observations and Recommendations on 2003 US Blackout Adaptive UFLS operation in 311 earthquake 3. Renewable Integrations 4. Summary

42 Summary 42 Experience of Voltage Collapse Has Enhanced TEPCO s expertise for Voltage & Reactive Management and Response Based P&C Scheme Has Secured Power System Stability Contributed to 2003 US-Canada Outage UFLS Saved Power System during 311 Earthquake from Blackout To Avoid Future Outage System Integrity Protection Scheme as System Wide Optimization

43 Top Down Approach; Start from Problems 43

44 Hierarchical Architecture for SIPS 44 Communication Network Control Center Phasor, Event Reports System wide Decision/EMS Coordination Coordination Phasor, Event Reports Phasor, SV, Status, Command Substation Phasor, SV, Status Monitor & Detect Local Decision Command Mitigate Phasor, Event Reports Coordination Phasor, SV, Status, Command Substation Phasor, SV, Status Monitor & Detect Local Decision Command Mitigate

45 Narrative of Functions 45 Combination of Fast and local control in substatons as lower layer Slow but wider view in control center EMS as higher layer Functions distributed in substations Monitor & Detect, Local Decision, Mitigation Response based controls which can react within one second after events and can revise control automatically based on measured system conditions Robust to unforeseeable power system dynamic performance in case of more renewables interconnections Functions in control center EMS State Estimation, Screening Engine, Optimal Power Flow, Dynamic Security Assessment Decision making from system wide of view based on information collected from substations Coordination signal sent to substations every several seconds Communication Network

46 Nerve systems metaphar 46 Higher layer in control system EMS Lower layer in substatons