Motor protection example

Assume you have a motor rated 500 HP, .95 power factor & 90 % efficiency energized from a 4.16 Kv source, using a microprocessor motor protection relay, provide the typical settings.

The full load current can be taken from the motor nameplate as well as the service factor. The motor full load current can be calculated from the following: I = 500 (.746)/1.732 (4.16)(.85)(.9) =60 amps.

To read more, click here.

Fault calculations & protective relays co-ordination studies:

Fault classifications: faults can be classified into symmetrical short circuit currents producing faults and unsymmetrical ones, another method of classification is whether it is of the shunt or series types. Shunt types faults can be further classified into: single line to ground, line to line, double line to ground, three phase grounded or ungrounded. The series types can be an open phase on one line or 2 open phases. These faults can be bolted or faulty through a resistance (impedance).

To read more, click here.

How-to use off-the-shelf software packages to perform power systems analysis

Chapter 1: Spread sheets fundamentals.
Chapter 2: Basic operation and fundamental calculations of power systems analysis.
Chapter 3: Fault calculations.
Chapter 4: Load flow studies.
Appendix A: Using Quickbasis to perform power systems studies.
Appendix B:Using HTML and Javascript to perform power systems studies.
Note: This on-line version of this book does not include the sketches and illustrations.

Computer Programming For Power Systems Analysts.

Chapter 1
INTRODUCTION TO COMPUTER PROGRAMMING:
Chapter 2
OVERVIEW OF THE ELECTRICAL POWER SYSTEM AND BASIC VALUES CALCULATIONS:
Chapter 3 FAULTS IN POWER SYSTEMS:
Chapter 4
LOAD FLOW STUDIES:
Chapter 5
TRANSIENTS IN POWER SYSTEMS:
Chapter 6
RELIABILITY STUDIES:
Chapter 7
STABILITY CALCULATION:
Chapter 8
ELECTRICAL POWER DISTRIBUTION MANAGEMENT INFORMATION SYSTEMS:
Chapter 9 (not available as an on-line version).
ENGINEERING ECONOMICS FOR POWER SYSTEMS ANALYSTS: (not available as an on-line version).

EPDMIS

Distribution systems data: constants of the Electrical Power System, circuit breakers and switchgear data plus other distribution system info, click here.

Power systems analysis tool (on-line)

It calculates (on the client side) the following: The equivalent of  parallel or series branches, Y to delta or vice-versa transformation, matrix manipulation & simultaneous equation solution, per unit calculation, Z-bus & Y-bus calculations; 3-phase, 2-line, 2-line-to- ground and line-to-ground fault currents for radial and network (grid) models; power flow (active & reactive) with motor starting effects & the effects of applying capacitors for radial & grid systems (with limited number of buses/configurations); reliability studies for utilities as well as industrial/ commercial/ institutional plants (for certain configuration; induced overvoltages due to lightning strokes, overvoltages due to direct lightning hits, overvoltages due to L.A. lead length & TRV (using the short method). To go to the on-line tool, click here.
Note: for stability analysis program, click here