China International Conference on Electricity Distribution 2014 (CICED2014) Shenzhen, China. September 23 26, 2014

Transcription

1 China International Conference on Electricity Distribution 2014 (CICED2014) Shenzhen, China September 23 26, 2014

2 American Electric Power (AEP) Overview Among the largest electric utilities in the United States Serving 5.3 M customers in 11 states Total Assets $ 56 B Generating Capacity 38 GW Electric Transmission Lines ~ 40,000 Mi. Electric Distribution Lines ~ 215,000 Mi. 2

3 American Electric Power (AEP) Overview $ 56 B ASSETS 5.3 M Customers In 11 states 40 K Line Miles OF Transmission 38 GW Generation 3

4 AEP Electric Transmission Infrastructure Owns and operates facilities in three RTO/ISOs through a variety of transmission companies Supplies approximately 10% of the demand in the Eastern Interconnection Owns, operates, and maintains highest capacity transmission in the USA ~2200 Mi. of 765 kv Pioneer in transmission technology and construction 4

5 Regional Transmission Organizations (RTO) 5

6 AEP Transmission History Introduction of 138 kv Introduction of 345 kv Introduction of 765 kv 36 Years 16 Years

7 Power Supply Considerations Safety Reliability Adequacy Cost effectiveness and consistency Resolve legacy issues Enhance operational flexibility Customer satisfaction Compliance with codes and standards 7

8 Transmission and Distribution Voltages Voltages 300 kv and above make up EHV Voltages 100 kv and above considered as bulk system and require adherence to NERC Standards/Criteria Voltages below 100 kv classified as subtransmission Voltages 34.5 kv and 12 kv are typically distribution radial network 8

9 Role of Transmission Analogous to the highway system Interstate Superhighways for electric power to move regionally and wide distances Provides the foundation for robust and reliable electric infrastructure Connects large and remotely located generation resources to the market Provides reliable exit points to serve load centers and distribution networks 9

10 Transmission Mission - AEP Assess the adequacy of AEP s transmission on a continuous basis and formulate plans to: Maximize asset value and utilization Meet reliability standards and compliance requirements Meet the electrical demands of customers including distribution 10

11 AEP In-Line Switching Considerations Switching arrangements at the tap point include: Group Operated Air Break (GOAB) switch and not part of the system automatic relaying scheme A GOAB switch equipped with automatic line sectionalizing capability is commonly referred as a Motor Operated Air Break (MOAB) switch A Circuit Breaker (CB) provides high-speed automatic sectionalizing capability to make or break circuits and interrupt fault currents 11

12 Transmission and Distribution Interface Challenges Transmission Station and Line Design Switching arrangements, relaying, exposure, interruptions, etc. Lightning and grounding Shunt capacitor switching surges and harmonics Voltage unbalance and reactive power supply Capacity/Adequacy 12

13 Transmission and Distribution Interface Challenges (cont d) Distribution System Design High side transformer switching Ground Switch/MOAB scheme CB, MOAB Switch, GOAB Switch, Fuses, etc. LTC vs Non-LTC Power Factor, Capacitors, etc. Distribution served from tertiary of Transmission transformers 13 12

14 Legacy Issues T&D Interface In-Line switching inadequacy in connecting Distribution Hard tap Manual switching Automatic switching without circuit breakers Limited installation of circuit breakers MOAB ground switch combination on the high side of step-down transformers Radial vs looped service Power Factor at the interface 14

15 Tap Station Definition and Functionality Any connection that results in only the associated load flowing through the connecting facilities under all conditions radial Radial line from an existing station or new station Radial line from an existing or new transmission line Establishment of in-line facilities to carry transmission power flows in addition to radial load 15

16 Transmission In-Line Switching Guidelines to Connect Load GOAB manual switching basic plan and minimum requirement MOAB automatic switching based on the calculation of Forced Outage Index (FOI) FOI =Load (L) X Miles of Exposure (M) X Permanent Forced Outage Rate (P) L = Peak load (in MW) that is directly jeopardized by the forced outage of the subject line M= Number of miles between two existing automatic sectionalizing devices (MOABs or CBs) plus new tap line length P = Permanent forced outage rate of the subject line (outages/year/mile) Install MOAB switches if FOI is equal to or greater than six (6) Note: Some exceptions are applicable on a case by case basis 16

17 Transmission In-Line Switching Guidelines to Connect Load (cont d) Circuit Breaker (CB) based on the calculation of Momentary Permanent Outage Index (MPOI) MPOI = Load (L) X Miles of Exposure X Forced Outage Rate (Permanent Forced Outage Rate (P) + Momentary Forced Outage Rate (M)) Install a CB if MPOI is equal to or greater than 200 Note: Some exceptions are applicable on a case by case basis including if power quality is a major concern due to forced momentary outages 17

18 T&D Interface Transformer Switching No MOAB ground switch combination on the high side of transformers Eliminate forced outage of the transmission line connected between CB terminals; avoid interruption of customers served from the intermediate tapped stations No high side fuses on transformers greater than 10 MVA served from 69 kv or below Above 69 kv, no fuses; high speed protection (CBs or similar devices) required 18

19 Looped Service vs Radial Service In general, looped service for Distribution load in excess of 30 MW Consistent with the typical large size Distribution transformer (30 MVA) Second transformer added when the load approaches MVA 19

20 T&D Interface Requirements No undue burden on the transmission system with respect to reactive power Close to unity PF AEP criteria is 99% PF Elimination of unacceptable transient voltages and harmonic resonance conditions due to capacitor switching comply with IEEE standards 20

21 Q & A? 21