AEP has been a leader in the development of transmission technology since the earliest
days of its history. AEP energized the first long-distance transmission line connecting
a mine-mouth power plant with a major load center in 1917.
Since that time, the company has continued the pursuit of new and better ways to
transmit electricity from its efficient fleet of power stations to the cities and
industries it serves.
| Year |
Event |
| 1917 |
First major mine-mouth power plant, Windsor Plant in West Virginia, and long-distance
transmission to load center, Canton, Ohio, 55 miles away |
| 1920 |
First application of carrier-current telephony to transmission lines for system
dispatching |
| 1926 |
Methods developed for transmission line lightning protection |
| 1929 |
First high-speed carrier-current relaying |
| 1929 |
First use of automatic frequency and tie-line load control |
| 1935 |
First ultra-high-speed (one cycle or 1/60th of a second), high-voltage reclosing
circuit breaker (138,000 volts) |
| 1937 |
First sleet melting of transmission line |
| 1947 |
First extra-high-voltage (EHV) line testing up to 500,000 volts, Tidd Project in Ohio |
| 1948 |
First aerial inspection of transmission line |
| 1951 |
First electronic line relay |
| 1953 |
First EHV transmission line (energized at 330,000 volts), between Sporn and Kanawha River stations in West Virginia |
| 1953 |
First hot-line maintenance of EHV line |
| 1958 |
First 345,000-volt interconnection, AEP System and Commonwealth Edison |
| 1960 |
First large-scale use of helicopters in transmission line construction |
| 1961 |
First two-cycle, high-voltage air-blast circuit breaker |
| 1961 |
First bare-hand maintenance of EHV line |
| 1961 |
First use of guyed-V aluminum tower for transmission line |
| 1961 |
First EHV transmission line testing up to 775,000 volts, Apple Grove Project in
West Virginia |
| 1962 |
First two-cycle, 345,000-volt air-blast circuit breaker |
| 1965 |
First field research in use of sodium as transmission conductor |
| 1966 |
First use of laser beam to monitor transmission line |
| 1969 |
First 765,000-volt transmission line, between Baker and Marquis stations in Kentucky
and Ohio, respectively |
| 1969 |
First two-cycle, 765,000-volt air blast circuit breaker |
| 1971 |
First 765,000-volt interconnection, AEP System and Commonwealth Edison |
| 1975 |
First 3,000 megavolt-ampere transformer bank, Marysville Station in Ohio |
| 1976 |
First sustained operation of ultra-high-voltage (UHV) line at 2,000,000 volts, AEP/ASEA
UHV Research Center at North Liberty, Indiana |
| 1978 |
First successful testing of transmission current-limiting device |
| 1978 |
First utility with 100 high-voltage or extra-high-voltage transmission interconnections |
| 1979 |
First operation of 765,000-volt station using sulfur hexafluoride (SF6) gas, rather
than air, as insulation< |
| 1979 |
First single-phase fault clearing and reclosing of untransposed 765,000-volt transmission
line |
| 1980 |
First application of Static Var System (SVS) to maintain voltage on transmission
grid, Beaver Creek Station in Kentucky |
| 1980 |
First use of microprocessors in substation protective relaying |
| 1984 |
First live-tank SF6 "puffer" type circuit breaker (765,000-volts), Jefferson
Station in Indiana |
| 1986 |
Nation's highest-capacity transmission network -- more than 2,000 miles of 765,000-volt
lines -- in commercial operation |
| 1991 |
Largest 345,000-volt series capacitor (788 megavolt-amperes) with thyristor control
east of Mississippi River, Kanawha River Station in West Virginia |
| 1994 |
First use of “open loop” shield wire design with gapped insulators on
EHV lines to reduce power losses |
| 1998 |
First Unified Power Flow Controller (UPFC) on transmission system, Inez Station
in Kentucky. |
| 1999 |
First transmission bridge capacitor, Leslie Station in Kentucky |
| 2000 |
First back-to-back asynchronous voltage-sourced converter, Eagle Pass Station in Texas |
| 2000 |
First use of 765,000-volt transmission surge arrestors instead of closing resistors
in circuit breakers |
| 2001 |
First dead-tank SF6 circuit breaker (765,000 volts), Orange Station in Ohio |
| 2006 |
First use of six-conductor phase bundles in U.S. for 765,000-volt line in AEP’s
Appalachian service area |
| 2006 |
First High Temperature Superconducting (HTS) triaxial cable demonstration, Bixby
Station in Ohio |
| 2007 |
First back-to-back HVDC with black start bypass breaker interconnecting AEP Texas
and Mexico transmission grids |
| 2007 |
First Variable Frequency Transformer (VFT) in US and on international border. Second
VFT in world. |
| 2010 |
First application of broadband over power line carrier (BPL) at 69 kV (2007) and 138 kV levels (2010). |
