maintenance for power generation and transmission

... assembling pieces of information on German and English discourse markers from grammars, dictionaries, and the linguistics research literature This information is classified and organized into a ... systematic lexical representations within a suitable formalism; and giving more attention to the requirements for text understanding in addition to those of generation References N Asher Reference to abstract ... goals of the generation process The generation task imposes a particular view of the information coded in DiMLex: the entry point to the lexicon is the discourse relation to be realized, and the lookup...

Ngày tải lên: 20/02/2014, 18:20

... Inequalities and Applications b If b h a t dg t ∈ I and either there exists an s ≤ t0 such that G t ≤ for t < s, G t ≥1 for s ≤ t ≤ t0 , G t ≤0 for t > t0 , 3.4 G t ≥1 for t0 < t < s, G t ≤0 for t ≥ ... Science and Engineering, Academic Press, Boston, Mass, USA, 1992 J Peˇ ari´ and A U Rehman, “On logarithmic convexity for power sums and related results,” Journal c c of Inequalities and Applications, ... continuous and convex for all x1 , x2 , x3 of an open interval I for which x1 < x2 < x3 , then x3 − x2 f x1 x1 − x3 f x2 x2 − x1 f x3 ≥ 2.4 Lemma 2.4 Let f be log-convex function and if, x1 ≤...

Ngày tải lên: 22/06/2014, 02:20

... continuous and convex for all x1 , x2 , x3 of an open interval I for which x1 < x2 < x3 , then x3 − x f x x1 − x f x x2 − x1 f x3 ≥ 2.4 Theorem 2.4 Let x and p be two positive n-tuples n ≥ and let ... r i p i xi − v, where r, t, u, v / 1, and f t ≤ u/s and v By raising power 1/s, we get 2.17 for r, t, u, v / s From Remark 2.8, we get 2.17 is also valid for r Corollary 2.10 Let Φs t ⎧ ⎪ ⎪ ⎪ ... Then ϕt x /x is a strictly increasing function for x > xt−2 > 0, for x > 0, therefore ϕt x /x is a strictly increasing function Proof Since ϕt x /x for x > Lemma 2.2 A positive function f is log...

Ngày tải lên: 22/06/2014, 02:20

... investigation and the economics (Smith and Rosa, 2007) As per the current statistics in GEO database, there are 130 high-throughput platforms for bovine, 89 platforms for porcine and 12 platforms for chicken ... enzmes involved in androstenone synthesis is given in Figure 2.6 3α-androstenol and 3β-androstenol are the final metabolites of androstenone in both testis and liver In liver, androstenone under ... discovery and data mining methods in livestock genomics for hypothesis generation and identification of biomarker candidates influencing meat quality traits in pigs Recent advancements in genomics and...

Ngày tải lên: 25/11/2015, 13:26

... collectors Performance 21 Concentrated solar power plant using parabolic trough design Concentrated solar power plant using parabolic trough design Central Receiver Power Plant Central Receiver Power ... Electric Generating System (SEGS) Central Receiver Power Plant Dish Sterling System Solar Chimney Power Plant Solar Pond Power Plant Temperature and concentration ratio of the various solar thermal ... capacity Pump Power requirement Efficiency 2.2 kW 1.6 kW 66.5% Pump between storage-tank and steam generator Water Pump    No of pump  Two pumps of 5.5 kW each are provided for feeding the...

Ngày tải lên: 27/01/2016, 13:10

... 40 and the total number of generations employed for converged solution is approximately 250 For both HAWT and VAWT wind farms, the size of the farm considered is 50D x 50D and a wind with uniform ... Journal of Energy and Environment (IJEE), Volume 3, Issue 6, 2012, pp.927-938 935 (a) Best, mean and median objective valuses for Case I (b) Standard deviations for Case I (c) Best, mean and median ... values for Case II (d) Standard deviations for Case II Figure Convergence history of the objective function (total power/ cost) for HAWT wind farm using GA with Werle’s wake model [5] for cases...

Ngày tải lên: 05/09/2013, 17:03

... Guide for Loading Mineral Oil-Immersed Transformers, ANSI=IEEE C57.91-1995 IEEE Guide for Protective Relay Applications to Power Transformers, ANSI=IEEE C37.91-1985 IEEE Guide for Transformer ... 1.3.1 Current Transformers Current transformer ratio selection and performance require special attention when applying transformer protection Unique factors associated with transformers, including ... Phase-Shift For transformers with standard delta-wye connections, the currents on the delta and wye sides will have a 308 phase shift relative to each other Current transformers used for traditional...

Ngày tải lên: 21/03/2014, 12:08

... shown in Eq (2.8) would be performed ANSI=IEEE standard limits are 1.05 pu for generators and 1.05 for transformers (on transformer secondary base, at rated load, 0.8 power factor or greater; 1.1 ... It is common practice for large generators to use two sets of voltage transformers for protection, voltage regulation, and measurement Therefore, the most common practice for loss of VT signals ... If above, the reverse power gets as low as 0.2 to 2% of the rated power and a sensitive reverse power relay is then needed With steam turbines operating at full vacuum and zero steam input, motoring...

Ngày tải lên: 21/03/2014, 12:08

... protection with transmission lines, buses, and transformers, each residing in its own zone Also shown are ‘‘closed zones’’ in which all power apparatus entering the zone is monitored, and ‘‘open’’ ... 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 ... distance between the relay location and the fault location As the power systems become more complex and the fault current varies with changes in generation and system configuration, directional...

Ngày tải lên: 21/03/2014, 12:08

... time, the process of power system cascading may start, leading to power system separation When a power system separates, islands with an imbalance between generation and load are formed One consequence ... the transmission lines, varying the operating conditions such as voltage profile and generation dispatch, coordinating relays and controls, and load shedding Most utilities rely on planning and ... PMUs, and performs data checks, records disturbances, and rebroadcasts the combined data stream to other monitor and control applications This type of unit fulfills the need for both hard and soft...

Ngày tải lên: 21/03/2014, 12:08

... 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 t ... voltages and currents For convenience in calculating the power in AC circuits from phasors, the phasor magnitude is set equal to the rms value of the sinusoidal waveform A sinusoidal quantity and ... frequency measurement, and wide area control 5.6 Algorithms 5.6.1 Parameter Estimation Most relaying algorithms extract information about the waveform from current and voltage waveforms in order to...

Ngày tải lên: 21/03/2014, 12:08

... response for permanent faults upon reclosure, and a ‘‘stuck’’ breaker In Fig 6.3 two waveforms are shown that depict adequate carrier response for internal and external faults The first waveform shows ... CTs are connected differentially around a transformer and the high side CTs not saturate (upper waveform) and the low side CTs saturate (lower waveform), the difference current will flow through ... bottom waveform depicts the response of carrier on an adjacent line for the same fault Note that carrier was ‘‘off ’’ initially and cut ‘‘on’’ shortly after fault initiation It stayed ‘‘on’’ for a...

Ngày tải lên: 21/03/2014, 12:08

... when active and reactive power flow through inductive reactances associated with the transmission network; this limits the capability of transmission network for power transfer The power transfer ... Design and Operation For reliable service, a power system must remain intact and be capable of withstanding a wide variety of disturbances Owing to economic and technical limitations, no power ... restore power consumption beyond the capability of the transmission system and the connected generation (Kundur, 1994; Taylor, 1994; Van Cutsem and Vournas, 1998) While the most common form of...

Ngày tải lên: 21/03/2014, 12:08

... Load and generation forecast: The design process must use forecast information about the amount, distribution, and characteristics of the connected loads as well as the location and amount ... the transmission system reactance; the larger the reactance (for example the longer or weaker the transmission circuits), the lower the maximum power Figure 8.3 shows that for a given input power ... acceleration and Area represents energy lost during deceleration Figures 8.6 and 8.7 show the rotor response (defined by the swing equation) superimposed on the power angle curve for a stable case and...

Ngày tải lên: 21/03/2014, 12:08

... J., and Fortin, S., A minimal realization approach to reduced-order modeling and modal analysis for power system response signals, IEEE Trans Power Systems, 8(3), 1020–1029, 1993 Kundur, P., Power ... of the system and therefore cannot be eliminated However, their damping and frequency can P be modified As power systems evolve, the frequency and damping of existing modes change and new E1E2 ... Definitions), Definition and classification of power system stability, IEEE Trans Power Systems, August 2004 Larsen, E.V and Chow, J.H., SVC control design concepts for system dynamic performance, Application...

Ngày tải lên: 21/03/2014, 12:08

... reactive power load levels) for this system For example, Fig 10.2 depicts the PV curves at the load bus obtained from these equations for k ¼ 0.25 and V1 ¼ pu when generator limits are neglected, and ... Bus voltage profiles and their sensitivity to variations in active and reactive power of the load and generators, or other reactive power sources Availability of reactive power supplied by generators, ... Pozzi, M., and Corsi, S., Comparing secondary voltage regulation and shunt compensation for improving voltage stability and transfer capability in the Italian power system, Electric Power Systems...

Ngày tải lên: 21/03/2014, 12:08

... area criterion (Kimbark, 1948; Anderson and Fouad, 1994) which is a direct method for determining transient stability for the one-machine-infinite-bus power system For a more detailed discussion ... of first swing transients For more details regarding the model, the reader is referred to Anderson and Fouad (1994), Fouad and Vittal (1992), Kundur (1994), and Sauer and Pai (1998) The assumptions ... satisfies kx(t)k < e for all t ! t0 The symbol k Á k stands for a norm Several norms can be defined on an n-dimensional vector space Refer to Miller and Michel (1983) and Vidyasagar (1978) for more details...

Ngày tải lên: 21/03/2014, 12:08

... portions of a power system 12.2 Concepts of Power System Stability Controls Figure 12.5 shows the general structure for analysis of power system stability and for development of power system stability ... power pool transient stability and load shedding controls for generation load imbalances, IEEE Transactions on Power Apparatus and Systems, PAS-100(7), 3486–3495, July 1981 48 Samuelsson, O and ... generator current is very high for the short circuit, the power factor, and active current and active power are close to zero.) Other switching (discrete) events for stabilization such as line...

Ngày tải lên: 21/03/2014, 12:08

... Engineering for Power) , 105(1), October 1983, 865–869 Standard load models for power flow and dynamic performance simulation, IEEE Transactions, PWRS10, August 1995, Static Var compensator models for power ... (OEL) Power transformer Terminal voltage and current Voltage sensing and compensation Underexcitation limiter (UEL) Generator flux (Volts/Hertz) limiter Power system stabilizer FIGURE 13.4 Power, ... that constant current be used for the real power and constant impedance for the reactive power, with frequency ß 2006 by Taylor & Francis Group, LLC factors of and 2, respectively This is based...

Ngày tải lên: 21/03/2014, 12:08

... performance must consider both its network performance, and its performance as an RMS transducer for steady stand and dynamic information on the power system All of these are major issues, and ... PMU for California–Oregon transmission project tests of March 1993, IEEE Transactions on Power Delivery, 11, July 1996, pp 1224–1231 37 PC37.118=D7.3 Draft Standards for Synchrophasors for Power ... the data And, expanding upon Rule #2, for any large power system we have Rule #4 Procedures and toolsets for analysis of the WAMS database must permit integrated analysis of – Measured power system...

Ngày tải lên: 21/03/2014, 12:08