re-futures study

8/10/2019 re-futures study

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A. POWER SYSTEM OPERATIONS


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This section discusses several elements of power system operations, including

forecasting and the day-ahead schedule or unit commitment, within-a-day

economic dispatch, frequency response and control , and operating reserves.


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A1. SECURITY-CONSTRAINED UNIT

COMMITMENT


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If a large thermal generator is suddenly lost, the instantaneous impact of

such a loss to the surrounding power system and system operatingreserves requirements is depicted in Figure above. Turbine speed

governors and the systems automatic generation control (AGC) sense a

drop in system frequency and initiate corrective action to increase

power from generators that are still operating.


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Unit commitment is a process of determining which generating units that

will be needed for the next day, and ensuring that any large thermalunits started and synchronized to the grid. This process is based on the

day-ahead load forecast, an estimated 2-3% of the peak load. The aim

of this process is for the solution of every economic problem.

in this process, many of the risks faced, either too much or too little

capacity is committed. operating reserves appeared to be the solution

of these problem.


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A2. ECONOMIC DISPATCH AND LOAD

FOLLOWING


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Economic dispatch is the short-term determination of the optimal output

of a number of electricity generation facilities, to meet the system load,at the lowest possible cost, subject to transmission and operational

constraints. In order to serve load at minimum total cost, the set of

generators with the lowest marginal costs must be used first, with the

marginal cost of the final generator needed to meet load setting the

system marginal cost.


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A3. FREQUENCY RESPONSE AND

CONTROL


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The value of Frequency Control is 60 Hz. If there is deviation from 60 Hz,

its indicates that there is a problem in the power system, the larger thedeviation, the bigger the problem. Abnormal frequency will damage the

power system, especially large steam turbines. While Frequency

response from generators actually helps protect the turbines from

abnormal frequencies by limiting the magnitude of the frequency

change during events.


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B. TRANSMISSION TECHNOLOGY AND

INSTITUTIONAL ISSUES


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This chapter provides a brief overview of transmission technology and then

an introduction to the basic institutional issues.


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Worldwide, the transmission technologies in use and functioning today,

either broadly or in initial installations, for transmitting bulk electricalpower are high, extra-high, and ultra-high-voltage AC transmission

systems up to 1,000 kV (Global Transmission 2009); high and ultra-

high-voltage DC transmission systems; and underground cables. The

current motivation for pursuing new higher capacity transmission

technology is the growth of large regional markets and the opportunity

for greater economic exchange.


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AC&HVDC TRANSMISSION SYSTEMS


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HIGHER VOLTAGES

AND SUPERCONDUCTING CABLES


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3. Higher Voltages

The advantage of using higher voltages is the decline in per unitcosts; the disadvantage is the risk of losing a larger portion oftransmission capacity in a single contingency failure.

4. Superconducting Cables

These cables use high-temperature superconductor materialsinstead of copper or aluminum and have substantially higherpower handling capabilities at lower voltages than conventionalcables. however, there are parasitic refrigeration losses. Thecommercial competitiveness remains to be fully demonstrated inthe market. As this technology is not commercial, it was notincluded in RE Futures transmission modeling.


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B.2 TRANSMISSION AND INSTITUTIONAL

ISSUES


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1. State and Federal Jurisdictions

the regulatory and economic drivers affecting transmission planning aresplit among the federal government and the states.

2. Siting, Permitting, and Right-of-Way Acquisition

Currently, the siting and permitting of transmission lines is the

responsibility of individual states.

3. Transmission Cost Allocation

Transmission cost allocation is controversial and one of the most important

issues to resolve if significant transmission system expansion is to be

realized.

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