concept of energy transmission and distribution

... all possible transmission levels or only a subset of them The P values are not dynamic and can be calculated beforehand for each of the transmission power level based on the chosen energy model ... Emitted energy Energy consumption Figure 16: Trade off between minimum energy consumption and energy emission power level to be chosen The effect is fewer packet losses, fewer retransmissions, and ... PDR-table and expected energy emission and consumption for IEEE 802.11 14 15 EURASIP Journal on Wireless Communications and Networking larger transmission power levels From Figures 2(c) and 3(c),...

Ngày tải lên: 21/06/2014, 11:20

... (> 45 Km) 32 Energy Transmission and Grid Integration of AC Offshore Wind Farms Opening year The new offshore wind farms and offshore wind farm projects are bigger and bigger and at longer distances ... penetration of wind power in electricity consumption are: Portugal (14.8%), Spain (14.4%) and Ireland (10.1%) Energy Transmission and Grid Integration of AC Offshore Wind Farms share % Finland Czech ... >30 m Countries with offshore wind Average turbine size Table 3.2 Evolution of the offshore wind energy and future trend Offshore Wind Farms 33 3.2 Offshore wind farms energy transmission system...

Ngày tải lên: 28/06/2014, 17:20

... Planning and Efficiency Initiatives Transmission and Distribution Planning Criteria Subtransmission GMP’s standard subtransmission voltages are 34.5 kV, 46 kV and 69 kV Using the subtransmission ... Planning and Efficiency Initiatives Transmission and Distribution Planning Criteria Subtransmission GMP’s standard subtransmission voltages are 34.5 kV, 46 kV and 69 kV Using the subtransmission ... Planning and Efficiency Initiatives Transmission and Distribution Planning Criteria Subtransmission GMP’s standard subtransmission voltages are 34.5 kV, 46 kV and 69 kV Using the subtransmission...

Ngày tải lên: 09/12/2015, 10:20

... 1886 by Professor Galileo Ferraris in Turin, opened the way for the adoption of alternating current and the rapid expansion of electrical transmission and distribution systems Transmission of electric ... transformer is not the sum of the maximum demands of each of the consumers connected to it, but a “new” maximum demand of the whole; this is because the maximum demands of each of the individual consumers ... group of consumers Here, the combined maximum demand of the group is compared to the total of the maximum demands of each of the members of the group, and this ratio is known as the diversity factor,...

Ngày tải lên: 18/02/2014, 22:20

... Strong drink and games of chance, and idols and divining arrows are only an infamy of Satan’s handiwork Leave it aside in order that ye may succeed” (Quran 5: 90) Blood, pork, and the meat of dead ... harmful and dirty creatures like flies, and lice are also prohibited as food Eggs and milk from permitted animals are also allowed “He hath forbidden you only carrion, and blood, and swine flesh, and ... Allah, and the strangled, and the dead through beating, and the dead through falling from a height, and that which hath been killed by (the goring of) horns, and the devoured of wild beasts saving...

Ngày tải lên: 13/03/2014, 22:08

... can be of the order of tens of amperes for tens of minutes, and flow into the neutrals of grounded transformers, biasing the core magnetization The effect is worst in single-phase units and negligible ... the rate -of- degradation, i.e., rate-ofloss -of- life of the insulation for overload assessment purposes Heating Due to Overexcitation: Transformer core flux density (B), induced voltage (V), and frequency ... maintenance and cost advantages found with power fuses Protection and control devices, circuit breakers, and station batteries are required The overcurrent relays are a small part of the total cost and...

Ngày tải lên: 21/03/2014, 12:08

... because of the machine’s inertia, the impedance ZR moves slowly The phenomenon can be taken advantage of and an out -of- step condition will very often be detected by the combination a mho relay and ... Implementation of an out -of- step protection will normally require some careful studies and eventually will require some stability simulations in order to determine the nature and the locus of the stable and ... regardless of the value of the frequency or the generator’s speed A software digital phase-locked loop allows implementation of such a scheme and will inherently provide a direct measurement of the...

Ngày tải lên: 21/03/2014, 12:08

... withstand an incorrect tripout (loss of security), whereas a failure to trip (loss of dependability) may be catastrophic in terms of system performance 3.1.2 Zones of Protection The property of ... amount of time to arrive at a decision with the necessary degree of certainty The relationship between the relay response time and its degree of certainty is an inverse one and is one of the ... at 138 kV and above, subtransmission lines are 34.5 kV to 138 kV, and distribution lines are below 34.5 kV These are not rigid definitions and are only used to generically identify a transmission...

Ngày tải lên: 21/03/2014, 12:08

... causes a higher frequency of oscillations, which enables faster calculation of the actual rate of change of frequency However, it causes faster rate of change of frequency and consequently, a larger ... characteristics of a particular system and the utility practices While the system frequency is a consequence of the power deficiency, the rate of change of frequency is an instantaneous indicator of power ... Adaptive settings of frequency and frequency derivative relays may enable implementation of a frequency derivative function more effectively and reliably 4.3 Transient Stability and Out -of- Step Protection...

Ngày tải lên: 21/03/2014, 12:08

... description of the state x, and recursively updates the estimate of state The initial assumption about the state is that it is a random vector independent of the processes wk and vk and with a ... finite energy and be a bandpass signal) For example, h(t) could be the output of a bandpass filter It is also true that it is only necessary to know the Wavelet Transform at discrete values of s and ... with the down arrow and a represents the process of taking every other sample For example, on the first line the output of the bandpass filter only has a bandwidth of B=2 Hz and the samples at TS...

Ngày tải lên: 21/03/2014, 12:08

... after the fault cleared and stayed ‘‘off ’’ all during the reclose ‘‘dead’’ time and after restoration of load current Both of these waveforms would be classified as ‘‘good’’ and would not need further ... A MAGNITUDE B D.C OFFSET RESTRIKE FIGURE 6.2 Use of oscillograms as a maintenance tool cycle fault and its corresponding carrier response A momentary burst of carrier is cut off quickly allowing ... CURRENT C A B C DEAD TIME LINE LOAD CURRENT CHARGING NEUTRAL CURRENT OFF RECEIVED CARRIER FIGURE 6.1 OFF OFF ON LINE OFF LINE Analysis of an oscillograph record signal on line was ‘‘on’’ all during...

Ngày tải lên: 21/03/2014, 12:08

... attention of the public and of regulatory agencies, as well as of engineers, on the problem of stability and importance of power system reliability Until recently, most industry effort and interest ... evolved and of the developments of methods for their analysis and mitigation is presented Requirements for consideration of stability in system design and operation are discussed 7.1 Basic Concepts ... Because of the high dimensionality and complexity of stability problems, it is essential to make simplifying assumptions and to analyze specific types of problems using the right degree of detail of...

Ngày tải lên: 21/03/2014, 12:08

... (kg Á m2) made up of the inertia of the generator and the prime mover and therefore J dvm ¼ Ta ¼ Tm À Te dt (8:2) where t is time in seconds and vm is the angular velocity of the machine rotor ... relationship and describes the transmitted power as a function of rotor angle It is clear from Eq (8.9) that the maximum power is a function of the voltages of the generator and infinite bus, and more ... duration) meaning that A1 > A2 and the rotor continues to advance and does not recover 8.3 Methods of Analysis of Transient Stability 8.3.1 Modeling The basic concepts of transient stability presented...

Ngày tải lên: 21/03/2014, 12:08

... advancing the understanding of power system dynamics Of particular interest is the study of modes and modal interactions that result from the combination of the individual system modes of the linearized ... an element of the matrix of right eigenvectors of the system state matrix (U), zj0, zk0, and zl0 are the initial conditions of transformed variables, and C j kl is the klth element of the matrix ... pressures of the continuing extension of electric networks and of increases in line loading have shown that the PSS alone is often not enough When we push to the limit that limit is more often than...

Ngày tải lên: 21/03/2014, 12:08

... Definition and classification of power system stability, IEEE Transactions on Power Systems, 19, 1387–1401, 2004 Lof, P.-A., Smed, T., Andersson, G., and Hill, D.J., Fast calculation of a voltage ... value decomposition and modal techniques should be of particular interest to the reader and are thoroughly described by Mansour (1993), Lof et al (1992, 1993), Gao et al ˜ (1992), and Canizares (2002) ... these Jacobians, and their sensitivities with respect to various system parameters Bus voltage profiles and their sensitivity to variations in active and reactive power of the load and generators,...

Ngày tải lên: 21/03/2014, 12:08

... Union Institute of Scientific and Technological Information and the Academy of Sciences of the USSR (in Russia) Criteria of Stability of Electric Power Systems Electric Technology and Electric Power ... Tavora and Smith obtained expressions for the total kinetic energy of the system and the transient kinetic energy, which the authors say determines stability This was followed by work of Gupta and ... mention of the applications of the technique and enhancements in terms of modeling detail and application to realistic power systems is provided Inclusion of detailed generator models and excitation...

Ngày tải lên: 21/03/2014, 12:08

... thousands of kilometers in very large power systems Thousands of generators must operate in synchronism during normal and disturbance conditions Loss of synchronism of a generator or group of generators ... consists of two 330-MW units and two 700-MW units The microprocessor-based controller measures rotor speed and generator power and computes acceleration and angle Tripping of 16–100% of plant ... stability and transfer capability problems must be solved by new controls and new substation equipment, rather than by new transmission lines Different ownership of generation, transmission, and distribution...

Ngày tải lên: 21/03/2014, 12:08

... equivalent circuit, and Ll represent the resistance and leakage inductance of the generator stator, Lad and Laq represent the mutual inductance between stator and rotor, and the remaining elements ... of the system For the DC and most of the AC excitation systems, the AVR controls the field of the exciter Therefore, the speed of response is limited by the exciter’s time constant The speed of ... starting time and is a function of the length of the penstock and other physical dimensions For high-head hydro plants with long penstocks and surge tanks, more detailed models of the hydraulic...

Ngày tải lên: 21/03/2014, 12:08

... validation and refinement of planning models – commissioning or recertification of major control systems – calibration and refinement of measurement facilities Refinement of planning, operation, and control ... They offer the promise of standardized measurements that greatly improve upon the quality of their analog predecessors, and of information networks that provide detailed real-time portraits of ... from = WECC staff This and related Web sites are routinely used for off-line exchange of data, working documents, and software associated with WAMS operation 14.2 Examples of Dynamic Information...

Ngày tải lên: 21/03/2014, 12:08

... tenths of seconds Milliseconds to seconds Hundredths of seconds to tens of seconds Tenths of seconds to hundreds of seconds Seconds to thousands of seconds dynamics ranging from hundredths of seconds ... transient One of the most basic concepts of system stability is the issue of maintaining synchronous operation of the AC generators This is usually referred to as ‘‘transient stability,’’ and is discussed ... states Very early power systems were often separate and isolated regions of generators and loads As systems became larger and more interconnected, the possibility of disturbances propagating long...

Ngày tải lên: 21/03/2014, 12:08