Understanding Generator Stator Ground Faults
... As the machine rating increases above about 100 MW, the form-wound coils become so stiff that it is nearly impossible to insert them into the narrow stator slots without damaging the coils. Therefore, most large generator coils today are not constructed using multiturn coils but rather are construct ...
... As the machine rating increases above about 100 MW, the form-wound coils become so stiff that it is nearly impossible to insert them into the narrow stator slots without damaging the coils. Therefore, most large generator coils today are not constructed using multiturn coils but rather are construct ...
1 General - Eskom Board
... a. Voltage depressions of medium duration can be caused by the switching of load such as induction motors. b. The supply voltage can fall as low as 75% of nominal value and the duration of this depression can be up to 10 seconds. c. An alternative source of this abnormal condition is when power swin ...
... a. Voltage depressions of medium duration can be caused by the switching of load such as induction motors. b. The supply voltage can fall as low as 75% of nominal value and the duration of this depression can be up to 10 seconds. c. An alternative source of this abnormal condition is when power swin ...
Using Rogowski coils for transient current
... constant. For example, the transient shown in Fig. 8 had With some transient measurements, there is no an offset lasting for more than a second. Where necessary opportunity to test the measuring equipment a Rogowski coil system can be designed to accommobeforehand at full current and the ‘real thing ...
... constant. For example, the transient shown in Fig. 8 had With some transient measurements, there is no an offset lasting for more than a second. Where necessary opportunity to test the measuring equipment a Rogowski coil system can be designed to accommobeforehand at full current and the ‘real thing ...
Effect of Neutral Grounding Methods on the Earth Fault
... A fault on a power system is an abnormal condition that involves failure risks of power system equipment. Generally, two types of failures can occur. The first is an insulation failure that results in a short circuit fault. The second is a failure that results in an interruption of current flow. Sho ...
... A fault on a power system is an abnormal condition that involves failure risks of power system equipment. Generally, two types of failures can occur. The first is an insulation failure that results in a short circuit fault. The second is a failure that results in an interruption of current flow. Sho ...
Interface Between Process Equipment And Process Bus for Light
... over an Ethernet link called process bus. As this thesis is the Part-A and it is mainly based on the development of the conventional instrument transformers, analog to digital data converter and a multi-bus power system. The scope of this study contains the development of current and voltage transfo ...
... over an Ethernet link called process bus. As this thesis is the Part-A and it is mainly based on the development of the conventional instrument transformers, analog to digital data converter and a multi-bus power system. The scope of this study contains the development of current and voltage transfo ...
Design and evaluation of a low thermal electromotive
... measurements, and guarded scanners may improve the uncertainty of these measurements. Guarded scanners can be used in applications where shielded or guarded multiple standards or components are connected to a measurement sys-tem. Automated switching not only relieves an operator of tedious measureme ...
... measurements, and guarded scanners may improve the uncertainty of these measurements. Guarded scanners can be used in applications where shielded or guarded multiple standards or components are connected to a measurement sys-tem. Automated switching not only relieves an operator of tedious measureme ...
Neutral Switching Transients
... * As we examine each option, we must scrutinize the claim of some that 3-pole transfer switches with overlapping neutrals offer a benefit of lower neutral switching transients when compared to 4-pole switches. Are neutral switching transients a problem on a 4-pole system? As we will see, both labora ...
... * As we examine each option, we must scrutinize the claim of some that 3-pole transfer switches with overlapping neutrals offer a benefit of lower neutral switching transients when compared to 4-pole switches. Are neutral switching transients a problem on a 4-pole system? As we will see, both labora ...
Guide to Commercial Installations Distribution Boards
... Compliance with standards A fundamental principle of BS 7671 is that all equipment must comply with the appropriate British Standard. For distribution boards BS EN 60439-3 is applicable. If equipment has a foreign standard based on an IEC standard then the designer or specifier must confirm that any ...
... Compliance with standards A fundamental principle of BS 7671 is that all equipment must comply with the appropriate British Standard. For distribution boards BS EN 60439-3 is applicable. If equipment has a foreign standard based on an IEC standard then the designer or specifier must confirm that any ...
Smart grid implementation in power system Subtitle
... A feeder circuit will have a voltage drop related to the impedance of the line and the power factor ...
... A feeder circuit will have a voltage drop related to the impedance of the line and the power factor ...
Selecting cables and fuses Lesson Element
... with the maximum current drawn by the device. This is due to the limited range of fuses. In other applications, a wider range of fuse current ratings may be available allowing selection of a fuse current rating closer to the maximum permissible value. Alternatively equipment may be internally protec ...
... with the maximum current drawn by the device. This is due to the limited range of fuses. In other applications, a wider range of fuse current ratings may be available allowing selection of a fuse current rating closer to the maximum permissible value. Alternatively equipment may be internally protec ...
Surge Protection Portfolio
... Protect a home or business owner’s investments with surge protective devices that are backed with both product and connected equipment warranties. Intermatic’s Type 1 and 2 SPDs offer the industry's best ratings and state-of-the-art surge protection technology. ...
... Protect a home or business owner’s investments with surge protective devices that are backed with both product and connected equipment warranties. Intermatic’s Type 1 and 2 SPDs offer the industry's best ratings and state-of-the-art surge protection technology. ...
Uninterruptible Power Supplies (UPS)
... Adequate Secondary Surge Protection The advantages of installing a Surge Protective Device (SPD) on a facility's service entrance are well documented and acknowledged as being essential in protecting sensitive electronic equipment from outside sources of transient voltages such as lightning strikes ...
... Adequate Secondary Surge Protection The advantages of installing a Surge Protective Device (SPD) on a facility's service entrance are well documented and acknowledged as being essential in protecting sensitive electronic equipment from outside sources of transient voltages such as lightning strikes ...
26 18 39 simovac-ar™ arc-resistant, medium
... furnished differs from the configuration tested. The acceptance criteria for the certification of the equipment shall be based on the ability of the equipment to retain its functionality and be returned to service immediately after a seismic event as outlined in the above requirements without the ne ...
... furnished differs from the configuration tested. The acceptance criteria for the certification of the equipment shall be based on the ability of the equipment to retain its functionality and be returned to service immediately after a seismic event as outlined in the above requirements without the ne ...
101 basics series starters and contactors
... So, how exactly does the contactor open and close? The E-Frame, when energized by the coil, becomes an electromagnet. The armature, a companion to the Eframe, is connected to a set of contacts. The armature is moveable but is held by a spring. When the coil is energized, the moveable contacts are pu ...
... So, how exactly does the contactor open and close? The E-Frame, when energized by the coil, becomes an electromagnet. The armature, a companion to the Eframe, is connected to a set of contacts. The armature is moveable but is held by a spring. When the coil is energized, the moveable contacts are pu ...
Impacts of Shunt Reactors on Transmission Line Protection
... and zero-sequence impedances. Effectively, the mutual inductive susceptance between the phases does not exist, and there is no neutralization of capacitive current. The appendix includes the circuit diagram and details of a model power system implemented in a Real Time Digital Simulator (RTDS®). We ...
... and zero-sequence impedances. Effectively, the mutual inductive susceptance between the phases does not exist, and there is no neutralization of capacitive current. The appendix includes the circuit diagram and details of a model power system implemented in a Real Time Digital Simulator (RTDS®). We ...
Document
... A comprehensive range of types and sizes of Search Coils are available for use with this Detector. All the Coils are housed in a fiberglass housing which is robust as well as being light and relatively easy to keep clean. There are two basic types of Search Coils, these being the Standard Coil, prim ...
... A comprehensive range of types and sizes of Search Coils are available for use with this Detector. All the Coils are housed in a fiberglass housing which is robust as well as being light and relatively easy to keep clean. There are two basic types of Search Coils, these being the Standard Coil, prim ...
MV Circuit Breaker Switchgear 38 kV
... The relays shall have adjustable maximum voltage pickup setting by a jumper between 60 V and 240 V. Feeder protection – advanced overcurrent with communications. a. The relays shall be SIEMENS 7SJ61 or equivalent. The relays shall provide with the following protection functions: 50/51, 50N/51N, 49 a ...
... The relays shall have adjustable maximum voltage pickup setting by a jumper between 60 V and 240 V. Feeder protection – advanced overcurrent with communications. a. The relays shall be SIEMENS 7SJ61 or equivalent. The relays shall provide with the following protection functions: 50/51, 50N/51N, 49 a ...
Simulation of the Currents Involved in Rhythmic Oscillations in
... membrane potential at which activation is measured remains fixed (Hagiwara and Ohmori 1982; Regan 199 1). Therefore, if we assume that the equilibrium potential is constant, then the driving force (E - EEq) remains fixed, and normalized tail current amplitude can be used as a measure of the T-channe ...
... membrane potential at which activation is measured remains fixed (Hagiwara and Ohmori 1982; Regan 199 1). Therefore, if we assume that the equilibrium potential is constant, then the driving force (E - EEq) remains fixed, and normalized tail current amplitude can be used as a measure of the T-channe ...
Protective relay
In electrical engineering, a protective relay is a device designed to trip a circuit breaker when a fault is detected. The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current, over-voltage, reverse power flow, over- and under- frequency. Microprocessor-based digital protection relays now emulate the original devices, as well as providing types of protection and supervision impractical with electromechanical relays. In many cases a single microprocessor relay provides functions that would take two or more electromechanical devices. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays. However, due to their very long life span, tens of thousands of these ""silent sentinels"" are still protecting transmission lines and electrical apparatus all over the world. An important transmission line or generator unit will have cubicles dedicated to protection, with many individual electromechanical devices, or one or two microprocessor relays.The theory and application of these protective devices is an important part of the education of an electrical engineer who specializes in power systems. The need to act quickly to protect circuits and equipment as well as the general public often requires protective relays to respond and trip a breaker within a few thousandths of a second. In these cases it is critical that the protective relays are properly maintained and regularly tested.