POWER LINE EFFICIENCY ANALYSIS

Presented by Wade ReynoldsJames Madison University – ISAT 493 Senior CapstoneSponsored by Shenandoah Valley Electric Cooperative

INTRODUCTION

In 2010, nearly 8 GWh were lost from transmission and distribution in Virginia alone

Equivalent to enough energy to power 1.3 million homes

ELECTRICITY SUPPLY CHAIN

eex.gov.au

IMPORTANT EQUATIONS

Power = Current x Voltage Power Loss = Current2 x Resistance

PURPOSE

Determine power loss across system and find technological solutions that can be implemented to improve efficiency and reduce loss

BACKGROUND

The Rural Electrification Act of 1936 provided federal assistance for rural electrification

RECs are private, non-profit utilities owned by the customers they serve

Two types of RECs: Generation and Distribution

SVEC is a Distribution cooperative that serves nearly 90,000 customers across western Virginia

RESEARCH QUESTIONS

What are the sources of loss in the system?

Are technologies currently available to replace SVEC’s current technology and improve efficiency?

Are these technologies cost-effective? What will improved efficiency mean to

SVEC and its customers?

METHODOLOGY

SCADA software was used to find the current and voltage at five strategic points across the system

Focus is on losses due to inefficiency in conductors and transformers

All formulas and methods used are consistent with industry standards and relative to the desired level of accuracy we wish to achieve

CLOVER HILL SYSTEM

Clover Hill Line extends 10.6 miles from the Dayton Substation

Conductor type = 1/0 Raven ACSR A single substation transformer and

1,415 distribution transformers located along the line Substation transformer rated at 100 MVA

capacity Each distribution transformer rated at ~10

kVA capacity

CONDUCTOR EFFICIENCY

Calculating Impedance Resistance Reactance

Calculating Loss Total Impedance per unit length Power Loss = Current2 x Resistance

Calculating Efficiency Power Loss/Power Supplied

FORMULAS

Conductor Impedance: Ra = Resistance Xa = Reactance Xd = Construction Reactance Factor

Construction Reactance Factor: Xf = Inductive Reactance Spacing Factor ƒ = Frequency GMD = Geometric Mean Distance

CONDUCTOR ANALYSIS

Conductor Type Raven ACSR Quail ACSR Linnet ACSR Azusa AAAC

Size 1/O 2/O 336.4 123.3

Resistance @25°C 0.1633 0.1301 0.0517 0.166

Reactance @25°C 0.104 0.1017 0.0854 0.102

Total Impedance (Ω) 12.7 11.2 7.8 12.8

Power Loss (kW) 115.5 101.7 70.8 115.9

Efficiency % 96.59 96.99 97.91 96.57

Inefficiency Cost Per Year $ 87,736.46 $ 77,265.83 $ 53,804.58 $ 88,052.18

Conductor Cost $ 20,737.26 $ 23,685.10 $ 67,833.78 $ 20,333.17

INEFFICIENCY COST VS. CONDUCTOR COST

Raven ACSR

Quail ACSR Linnet ACSR

Azusa AAAC

$0

$10,000

$20,000

$30,000

$40,000

$50,000

$60,000

$70,000

$80,000

$90,000

Inefficiency Cost Conductor Cost

TRANSFORMER EFFICIENCY

Transformers incur two types of losses No-Load Load

TRANSFORMER ANALYSIS

Type Standard NEMA Premium

Capacity (kVA) 10 15

Efficiency 96% 98%

Average Yearly Load (kWh) 6,000 6,000

Loss Incurred (kWh) 234 96

# of Transformers 1,415 1,415

Total Loss (kWh) 331,110 135,840

Inefficiency Cost Per Year $ 28,707 $ 11,777

RESULTS AND FINDINGS

Linnet conductor will have a payback period of less than 2 years

NEMA Premium transformers will save nearly $17,000 annually in power losses

TECHNOLOGY SOLUTIONS

High-Efficiency Conductors ACCC cut line loss by 30-40% under equal

load NEMA Premium Efficient Transformers

Meet or exceed DOEs efficiency requirements

Smart-Grid Devices Two-way communication provides real-time

information to ensure system is operating at optimal levels

BENEFITS

Lower customer electricity bills Improved reliability Greater response to power outages Lower maintenance costs Reduced need for generating capacity Lower greenhouse gas emissions

BARRIERS

Inventory Replacement Costs Construction Costs Customer Resistance Cash on-hand

STRATEGY

Short-term (2 to 10 years) Replace blown-out transformers with high-

efficiency transformers Mid-range (11 to 20 years)

Replace old conductors with either high-efficiency conductors or larger ACSR conductors

Long-range (beyond 20 years) Install smart-grid devices across

distribution system

QUESTIONS?