SEASON'S GREETINGS on Dec 31, 2012To all our visitors, most especially to our followers and supporters, the Management and Staff of transmission-line.net and the MOSTECH Group would like to extend our greetings. Thank you for all the support and may you find our site informative and...
SELECTION OF SYSTEM VOLTAGE OF YOUR POWER INSTALLATION on Dec 17, 2012 in Transmission Lines Voltages The selection of the ac supply system voltage typically begins at the service entrance of the facility. In most commercial environments in the U. S., the utility supplies three-phase power at 480 Y/277 V (or 600 Y/347 V) or 208 Y/120 V. In indu...
WOODEN POLES FOR POWER LINES HOLE DIGING AND POLE SETTING on Dec 15, 2012 in Wood Poles Foundations The foundations for poles are just as important as the structure above ground. The pole backfill should be capable of withstanding structure reactions. Pole-setting equipment should be moved clear of the structure site prior to backfilli...
EFFECTS OF LOAD ON TRANSMISSION LINE RELAY APPLICATIONS AND SETTINGS on Dec 11, 2012 in protective relaying One of the principal influences on protective relay settings is load; hence, maximum load current level, in turn, may influence fault detection sensitivity. Phase overcurrent relays Phase overcurrent relays must be set to avoid operation on all...
HIGH VOLTAGE POWER CABLE SHIELDING PRACTICES BASIC INFORMATION on Dec 8, 2012 in Transmission Lines Voltages Power Cables shielding Cable shields and metallic sheath/armor should be solidly grounded at one or more points so that they operate at or near ground voltage at all times. For additional information see IEEE Std 575-1988. Accidental removal of the shield ground can cau...
GROUND POTENTIAL RISE BASIC INFORMATION AND TUTORIALS on Dec 6, 2012 in Fault grounding FACT ON GROUND POTENTIAL RISE What Is Ground Potential Rise? GPR When a ground fault occurs, the zero-sequence fault current returns to the power system ground sources through the earth and also through alternate paths such as neutral conductor...
GUIDE IN CREATING A SINGLE LINE DIAGRAM BASIC TUTORIALS on Nov 24, 2012 in single line diagram The following characteristics should help to ensure accuracy as well as ease of interpretation: a) Keep it simple. A fundamental single-line diagram should be made up of short, straight lines and components, similar to the manner in which a block...
CIRCUIT BREAKER SELECTION CRITERIA BASIC INFORMATION on Nov 17, 2012 in Circuit Breakers The selection of any circuit breaker, for any given duty, is ultimately based on an assessment of its ability to perform the following basic functions: a) To carry the required full-load current without overheating (i.e., it should have the correc...
PROTECTIVE RELAY COORDINATION BASICS on Nov 16, 2012 in protective relaying Insulation Coordination Coordination is a systematic application of current actuated devices in a power system, which in response to a fault or overload will remove only a minimum amount of equipment from service. The objective is to minimize the equipment damage. A coo...
DIFFERENTIAL RELAY PURPOSE AND FUNCTIONS BASIC INFORMATION on Nov 15, 2012 in protective relaying How Differential Relay Protect Your System? Differential relays provide high-speed (1 to 2 cycles), sensitive, and inherently selective protection. These will not provide protection for turn-to-turn winding faults in generators, motors, and transf...
