Power Plant Operator Training » Power Transmission

Control Performance Compliance

admin — Wed, 17 Jun 2009 19:23:41 +0000

This training module offers hands-on insight into the critical tasks of controlling, monitoring, and measuring system control performance.

Topics Covered

Control Performance Standards
Review of NERC Regions
Electricity System Control Review
Review of Dynamic Scheduling
ACE at NERC
ACE at WECC
WECC Inadvertent term
Electric System Control
Basic System Control
NERC Standards
CPS-CDS Control Highlights
CPS Review

High Voltage, Transmission, Safety, & Power System Ops

admin — Wed, 17 Jun 2009 19:16:20 +0000

This training module is great for the newcomer in system operations.

Topics Covered

Synchronizing Islands
Power Systems Operations
Safety Review
Basic Review of Power Systems Operations
EHV Operation
WECC ACE-PACE
AC EHV Terms
EHV and 500kV Basics
Single-Pole CB Tripping
Procedures and Communication

Synchronizing Islands

admin — Wed, 17 Jun 2009 19:13:03 +0000

This training module is great for the newcomer in system operations.

Topics Covered

Synchronizing Islands
Power Systems Operations
Safety Review
Basic Review of Power Systems Operations
EHV Operation
WECC ACE-PACE
AC EHV Terms
EHV and 500kV Basics
Single-Pole CB Tripping
Procedures and Communication

Undervoltage and Underfrequency

admin — Wed, 17 Jun 2009 19:06:17 +0000

This course is intended as an introduction to the concepts of underfrequency and undervoltage. During this lesson you will be asked to relate these concepts to NERC and WECC standards and to apply your knowledge of these relationships by answering a variety of questions. By the end of this lesson you should understand the different roles and relationships underfrequency and undervoltage maintain with many workplace practices.

Topics Covered

Frequency Control Terms
Dynamic Look at Underfrequency and Undervoltage
Frequency and Voltage Deficiency
Voltage Frequency Facts
Undervoltage and Underfrequency Facts

Voltage Control

admin — Wed, 17 Jun 2009 19:03:35 +0000

During this course, you will become familiar with both the NERC and WECC requirements concerning voltage control. Voltage control plays a substantial role in determining the success of electrical operations. As a result it is important to study voltage relationships and the impact of these relationships on various types of electrical systems handling various types of voltages.

Topics Covered

Voltage Relationships
Sine Wave Relationships
Capacitor Basics
Dynamic Worksheets
Review of NERC Terms

Monitoring and Control Communications

admin — Mon, 08 Jun 2009 19:20:04 +0000

The objective of this course is to look at different modes of communication that are employed in operation of the transmission system. Communication applications are demonstrated with particular emphasis upon the SCADA system as employed for system operation. After completion of this course and associated workbook, the participant should be able to understand the following concepts and apply them in day-to-day working activities.

At the end of this course you should be able to:

The need for communication as an integral part of transmission system operation
Techniques of communication employed in transmission system operation
Typical application of the different communication techniques
The function of the SCADA system
Collection of data by RTUs
Polling of RTUs throughout the system
Transfer of data across communication links
The need for carrier signals and modems
Factors affecting the rate of data transmission
Data transfer from RTUs to the CPU memory
Frequency of CPU update
Typical master station layout
CPU and peripheral computers and devices
Fail-over stand-by computer
Applications software
The operator interface
The operator display functions
Displaying equipment attributes
Alarm annunciation
Logging operating events
Features of SCADA installations

System Voltage Control

admin — Mon, 08 Jun 2009 19:16:54 +0000

This third course in the Transmission System Operation training program develops the principles of voltage control on the transmission network. The material builds upon discussions of power flow fundamentals and transmission line characteristics from the two previous courses.

We begin by describing the system’s need for reactive power (VARs) and how VARs are generated and/or absorbed by the various components of the power system. Next it is demonstrated that the flow of VARs has a profound effect on voltage level (much more so than the flow of Watts). Transmission line MW loading and its effect on VAR requirements and voltage are also examined, as well as the effect of contingencies.

Various real-life scenarios are described in which power systems have collapsed from significant off-nominal voltage. Finally, this course discusses a wide array of equipment and methods system operators can use to effectively control transmission voltages to comply with industry standards.

At the completion of this course, you should be able to:

Name the two distinct types of power produced at the generators when load is connected
Explain the basic difference in function between Watts and VARs, and why both types of power are necessary to make electrical equipment work
Sketch and compare curves for power in a purely inductive circuit and power in a purely capacitive circuit
Recognize the difference between positive VARs and negative VARs
Name 3 power system components that create a demand for VARs
Name 3 power system components that supply VARs to the system
Describe what it means for some components to “compensate” for others
Explain how MW and MVARs are produced in an electric generator
Recognize that a change in generator voltage or MVAR supply must come from a change in the unit’s DC excitation current
Discuss the function of an Automatic Voltage Regulator (AVR)
Predict the response of the AVR to an increase or decrease in MVAR demand on the system
Recognize that it takes a difference in voltage magnitude to drive MVARs through the system, and that the direction of MVAR flow is from high to low voltage
Discuss the function of a synchronous condenser and a static VAR compensator
Explain why a transmission line can be either a MVAR source or a MVAR load
Describe the effect of MVAR flow on voltage drop. Compare to the voltage drop resulting from the flow of MW
Name 3 events that can have a profound effect on MVAR flows and voltage level
Explain what happens to the MVARs required by a transmission line as MW loading is increased
State the significance of a line’s surge impedance loading (SIL)
Understand why it is important to have adequate MVAR sources located at intermediate points in the network, especially during contingencies
Sketch the voltage profile along a transmission line operating above SIL, with voltage at both ends fixed at 100%. Compare with the voltage profile below and at SIL
Explain why MVAR supply from a line’s capacitance drops off sharply at loadings above SIL
Name some typical loading levels for transmission lines in percent of SIL
Sketch a typical transfer limit curve (P vs. V) and explain the significance of the knee of the curve
Explain why line loadings must be restricted to well below the knee of the transfer limit curve
State the industry (NERC) limit for percent voltage change following any single contingency
Give examples of system conditions and events that may lead to voltage collapse.
Explain why it is important for system operators to prepare in advance for voltage emergencies
Describe how operators can adjust voltage/MVAR supply at the generating units
Understand why AVR set points must be raised/lowered in unison to effect a net change in voltage/MVAR supply
Sketch a typical generator capability curve and discuss the MW and lagging/leading MVAR limitations
Describe the function and operation of Maximum and Minimum Excitation Limiters on generating units
List some power system components that allow operators to adjust voltage/MVAR supply at locations other than generating plants
Discuss the reactive overload capability of generators, synchronous condensers, and static VAR compensators
Describe some typical applications for shunt reactor and capacitor banks on the transmission system
Explain how a series capacitor can be of assistance in voltage control
Understand the function and operation of Load Tap Changing Transformers (LTCs) in providing voltage correction on the transmission and distribution systems
Discuss the importance of operator actions in implementing voltage control: curtailing economy transfers, bringing on local generation, bringing on reactive sources ahead of the morning load rise, removing lines during light load, etc

Review of Fundamentals

admin — Mon, 08 Jun 2009 19:11:54 +0000

Review of Fundamentals The objective of this course, the first in the series on transmission system operation, is to review relevant fundamentals of electricity to provide a firm foundation on which to build an understanding of the more advanced concepts which will be presented as the program progresses.

On completion of this course, the participant should be able to understand the following concepts and apply them in day-to-day operation:

To provide unbiased control of system operation
The establishment of Independent System Operators (ISOs) or other similar entities
The tasks of the system operations group; controlling the transmission system
Frequency control of the power system through matching of power production and consumer demand plus losses
Load impedance and its effect on current flow through transmission lines
The effect of conductor resistance in a transmission line, i.e. voltage drop and energy loss due to heat dissipation
The effect of line voltage on system energy losses
The difference between power and energy, i.e. watts versus watt-hours
Typical power generator prime movers
Fundamentals of electric power generation
The sine wave and RMS values
Factors that determine frequency of generation
The effect of pure resistance in an AC circuit as shown by sine waves and vector diagrams
The effect of pure inductive reactance and capacitive reactance in an AC circuit
Power generated in resistive, inductive, and capacitive circuits
The flow of reactive power, positive and/or negative vars
The power triangle and power factor
Combined R, XL, and Xc circuits
The impedance triangle and voltage triangle
Power factor correction
The effect of transmission line inductance on voltage drop
The development of a power angle across a transmission line due to line inductance
Three phase power generation
The application of a common neutral conductor
A balanced three phase load with no neutral conductor
Voltage and current characteristics of the Wye and delta connections
The calculation of three-phase power
Current and voltage relationships between primary and secondary of a Delta/Wye connected transformer

Power Transmission

admin — Mon, 08 Jun 2009 19:08:32 +0000

The main objective of this course, the second in the series on transmission system operation, is to draw attention to the major features of transmission system equipment, and operation of transmission lines. Particular attention is paid to limitations resulting from the effects of resistance, inductance, and capacitance of the lines.

After completion of this cousre, the participant should understand the following concepts, and be able to apply them in day-to-day work activities.

Typical operating voltages for transmission lines and distribution lines
Different types of transmission towers
Conductor material and conductor layout on the towers
Insulators and the importance of conductor spacing
Features and limitations of transmission cables
The application of high voltage DC transmission
The effect of transmission line conductor resistance and inductance
Line voltage drop and power angle as shown by vectors
The effect of line loading on voltage drop and power angle
The effect of load power factor on voltage drop and power angle
The need to generate and provide megavars and megawatts to meet line losses
Charging current required due to the line shunt capacitance
Voltage rise due to line capacitance on an open-ended line, shown by vectors
Production of reactive power by line shunt capacitance
Line reactive compensation equipment, including: reactors, capacitors, synchronous condensers, and static VAR compensators
The function of transmission stations, and station equipment
Features of different bus arrangements
Types of circuit breaker
The principle of transformer operation
Transformer physical construction
Transformer cooling arrangements
Autotransformers
Instrument transformers

System Frequency and Tie-Line Control

admin — Mon, 08 Jun 2009 19:05:06 +0000

The fourth course in the Transmission System Operation training program shows how frequency and tie-line flows between control areas are controlled. We begin by developing the concepts of an AC interconnection and synchronizing forces. Frequency deviations come about when unbalances develop between generation and load and these deviations are controlled by the combined action of speed governors and Automatic Generation Control (AGC) aided by the natural change in load as frequency changes.

We describe how tie-line flows also change when generation to load imbalances occur. Finally, this course discusses Area Control Error (ACE), the fundamental input to AGC, and how it provides the intelligence required to restore generation to load unbalances.

At the completion of this course, the student should be able to:

Know what constitutes an AC interconnection
Identify the interconnection within which your facilities are located
Know at what frequency your interconnection operates
Explain why frequency is the same throughout an AC interconnection
Explain the role of transmission lines in maintaining synchronism
Know what causes frequency to deviate from nominal
Tell whether generation or load is changed to control frequency
Know what a speed governor is and what it does
Tell how the size of an interconnection affects frequency deviations
Know what limits are imposed on frequency excursions and why
Know why it is important to control tie-line flow
Know why the type of generating unit affects its speed of response to frequency changes
Explain the relationship between generation rotational speed and frequency
Understand that speed governors act as proportional controls
Describe what is meant by governor droop
Describe the units used for droop
Know that governors work to control both decreasing and increasing frequency
Understand why governor droop permits load sharing between generating units
Tell what are typical droop settings for various types of generating units
Understand why many classes of generating units do not participate in frequency control
Be able to describe the basic characteristics of the example system used
Total capacity, capacity under governor control and total load
Composite droop characteristic
Tell what happens to frequency under governor control only when an 800 MW unit trips off
Describe what is meant by the Load Effect
Describe what is meant by the Frequency Response Characteristic, Beta
Tell what happens to frequency under the influence of Beta when an 800 MW unit trips off
Be able to calculate how much generation is picked up and how much load is lost for a given drop in frequency
Understand why frequency does not drop instantly when a generation/load mismatch occurs
Be able to identify points A, B and C on a frequency chart taken while a generating unit tripped off line
Be able to compute the net tie-line flow following loss of generation within a control area
Understand how AGC assists system operators
Know how frequently AGC application software is run, typically
Be able to describe Area Control Error and how it is calculated
Know what is the Frequency Bias Coefficient, B, and how it relates to Beta
Be able to compute ACE given frequency deviation, net tie deviation and B
Know how to find the frequency stabilization point
Describe functions that AGC can perform other than responding to generation loss
Know why AGC is suspended when large frequency deviations occur