1

TRANSMISSION SYSTEM OVERVIEW TRANSMISSION SYSTEM OVERVIEW NETWORK OPERATING COMMITTEENETWORK OPERATING COMMITTEE

April 17, 2007April 17, 2007

New Mexico Transmission System New Mexico Transmission System OverviewOverview

2

Efficient Use of Existing Efficient Use of Existing Transmission SystemTransmission System

Long-term weather study (8 weather stations) Increased rating (18%) of transmission lines by using less

conservative wind speed assumptions

Real-time monitoring Installed monitoring equipment to allow for temporary

increase of emergency ratings based on actual (as opposed to worst-case) temperature and wind conditions

Traveling Wave Fault Recorders on all 230kV, 345kV line and key 115kV lines

Disturbance Monitors Bulk transformer online monitoring (oil, temperature, hot

spots)

Risk management (Video Sagometers) Several lines exposed to low-probability, short-duration

events have been rated for high-temperature operation

3

Efficient Use of Existing Efficient Use of Existing Transmission SystemTransmission System

4

Efficient Use of Existing Efficient Use of Existing Transmission SystemTransmission System

Reactive Compensation & Voltage Support Series compensation of 345 kV lines Shunt capacitors Albuquerque power factor control (RCCS)

Transmission Line Clearance Over 1500 miles of transmission lines have been phase-

raised to remove ground clearance limitations.

Emergency Procedures Automatic load shedding schemes, as safety net

measures, to handle deficiencies in transmission capability during peak usage during scheduled maintenance and forced repairs

Reactor contingency scheme

5

WECC/NERC CriteriaWECC/NERC Criteria

Planning and Operations CriteriaWECC/NERC Standards

Current System Capability with All Lines in Service (N-0)

    All facilities within normal rating limits   Voltage levels shall be within normal limits   Network stability shall be maintained   All customer demands shall be supplied and all firm transfers shall be maintained

Current System Capability with one line out of Service (N-1)

   All facilities within emergency ratings   No bus voltage drop greater than 5%   5% Real and Reactive Power Margins    Transient voltage dip should not exceed 20% for longer than 0.33 sec   Transient frequency dip should not exceed 59.6 Hz for longer than 0.1 sec

Current System Capability with two Lines out of Service (N-2)

   All Facilities within emergency ratings    No bus voltage drop greater than 10%   2.5% Real and Reactive Power Margins   Transient voltage dip should not exceed 20% for longer than 0.67 sec   Transient frequency dip should not exceed 59.0 Hz for longer than 0.1 sec

6

Generation InterconnectionsGeneration InterconnectionsA Few FactsA Few Facts

Received 50 generation interconnections since 2000 (42 direct interconnect and 8 are joint studies)

Signed 6 LGIA for a total of 768 MW 451 MW Wind 317 MW Gas and Bio Mass

Today’s Queue 5 Feasibility Studies 6 System Impacts Studies 4 Facility Studies

1562 MW Wind 1479 MW Gas and Combined Cycle

7

New Mexico Wind Energy New Mexico Wind Energy CenterCenter

Located in Eastern Located in Eastern New MexicoNew Mexico

204 MW capacity204 MW capacity Supplies up to 20% of Supplies up to 20% of

PNM’s total demand at PNM’s total demand at any given timeany given time

Supplies approximately Supplies approximately 3.5% on the average3.5% on the average

Installed in 2003, in Installed in 2003, in record time!record time!

Owned and operated Owned and operated by FPL Energy by FPL Energy

PNM purchases & PNM purchases & markets all the outputmarkets all the output

8

Technical SpecificationsTechnical Specifications

136 towers, each 210 feet tall Base circumference is > 40 feet! Wind Farm spread out over 15 miles

Three blades at top of each tower, each 110 feet in length

Facility feeds power onto nearby PNM high-voltage transmission line

9

How Wind Turbines Produce EnergyHow Wind Turbines Produce Energy

Blades rotate toward the wind Winds of 6 to 7 mph are enough to turn

blades Blades turn a shaft connected to the

rotor of an electric generator Mechanical components can withstand

winds of up to 55 mph

Person on top of rotor

10

NMWEC Power Output PatternNMWEC Power Output Pattern

PNM Load Pattern (08/03-PNM Load Pattern (08/03-08/04)08/04)

WinterPeak Load

Spring/FallLoad Valleys

Summer Peak Load

11

Questions?Questions?