high voltage power electronic substations

... to find out the costs of basic methods of forest land maintenance in protective zones of high- voltage power lines (HVPL) 400 kV in the protective zone of 70–80 m in width, and 220 kV in the protective ... results for making a decision which method of forest land maintenance in the zones under high- voltage power lines is economically effective and acceptable Calculations of costs to maintain the ... Hand cutting (using mechanical devices) is not used because of high manpower requirements and also because of its low productivity and high cost This option could be considered only if the stand...

Ngày tải lên: 07/08/2014, 10:21

... that the highest overvoltage will occur at system resonance, where the magnitude of the two reactances are equal At resonance, overvoltages of 20 times normal can be reached Substantial overvoltages ... power center, which steps down the 13.8-kV distribution voltage to the 4160-V utilization voltage and to the 480-V auxiliary voltage The power center feeds the 4160-V motor-starting unit, which ... expected, approximately equal to the line-to-line voltage of the system NOVAK: ANALYSIS OF VERY -HIGH- RESISTANCE GROUNDING IV CONCLUSIONS With high- voltage (greater than 1000 V) longwall mining systems,...

Ngày tải lên: 26/11/2015, 09:40

... supply voltage Figure 1.20: Torque–speed curves of an induction motor with reduced supply voltage V1 = Low level of supply voltage V4 = High level of supply voltage V5 = Full rated supply voltage ... constant power, reduced torque  Practical Variable Speed Drives and Power Electronics • The output power is zero at zero speed In the normal speed range and at constant torque, the output power ... (rev/min) 9550  Practical Variable Speed Drives and Power Electronics Torque (Nm) = 9550 × Power (kW) Speed (rev / min) • Energy Energy is the product of power and time and represents the rate at which...

Ngày tải lên: 08/09/2013, 21:03

... Supply Voltage Quiescent Circuit Current SYMBOL TEST CONDITIONS VCC ICC VIN=0 Stereo Closed Loop Voltage Gain Bridge Channel Balance DIP-8 SOP-8 Output Power( Stereo) DIP-8 SOP-8 Output Power (Bridge) ... CIRCUIT ABSOLUTE MAXIMUM RATINGS (Ta=25°C) PARAMETER Supply Voltage Output Peak Current SYMBOL VCC IO(peak) RATINGS UNIT 15 V A DIP-8 1.0 Power Dissipation PD W SOP-8 0.5 Operating Temperature TOPR ... www.unisonic.com.tw -1 0.4 0.28 VCC=3V,RL=4Ω, THD=10% DIP-8 SOP-8 DIP-8 SOP-8 Ripple Rejection Output Noise Voltage Cross Talk Input Resistance MIN 1.8 24 100 TYP 40 40 0.65 0.45 0.11 0.07 1.35 0.94 0.35...

Ngày tải lên: 12/09/2013, 10:00

... loop arrangement [1] However, most power electronics converters are circuits with controllable voltage output To achieve current control, the voltage of the power electronics converter can be controlled ... output voltage, while maintaining the desired ripple voltage Initial voltage overshoots during start-ups can sometimes damage loads that are sensitive to high voltages or they may trigger the overvoltage ... their high efficiency, compact size, and low cost, switching power supplies continue to gain popularity Switching power supplies could be as high as three times more efficient than linear power...

Ngày tải lên: 17/10/2013, 11:15

... armature voltage regulators With the SCR came increased efficiency, the ability to regenerate power, and high power capability DC drives and motors from a few horsepower to hundreds of horsepower ... (PWM) voltage regulators, the armature voltage for small motors could be controlled Systems up to several horsepower were successfully applied to DC motors using permanent magnet fields The power ... at the controlled voltage The speed of the connected motor is a function of the voltage supplied by the generator and the field current of the motor When the same DC generator powers several DC...

Ngày tải lên: 19/10/2013, 18:15

... that inductor current and capacitor voltage references are difficult to evaluate, because they generally depend on load power demand, supply voltage, and load voltage This is true for all basic ... voltage errors are chosen as state variables, i.e., ∗  x1 = i – I  ∗  x2 = uo – Uo (8.30) ∗ where the current reference I depends on the converter operating point (output power and input voltage) ... Trans Power Electron., 10(3), 302–309, 1995 10 P Mattavelli, L Rossetto, G Spiazzi, and P Tenti, General-purpose sliding-mode controller for DC/DC converter applications, in Proc of IEEE Power Electronics...

Ngày tải lên: 19/10/2013, 18:15

... The inverter DClink voltage is obtained through rectification of the AC line voltage The drive uses a simple pulse-widthmodulated (PWM) inverter whose time-average output voltages follow a reference-balanced ... between the input voltage magnitude and frequency takes the form V in = k f w e + V offset (11.6) where Voffset is a constant The purpose of this offset voltage is to overcome the voltage drop created ... torque–slip curves with varying input voltage magnitudes for a typical induction for developing rated torque throughout the entire speed range given a constant stator voltage magnitude An inverter is...

Ngày tải lên: 23/10/2013, 16:15

... drives Their high power density makes them ideal candidates for applications such as robotic actuators, computer disk drives, and office equipment With their high efficiency, high power factor, ... length in the direction of magnetization and a high coercivity A high power density also requires the largest possible magnet volume Exposure to high temperatures tends to deteriorate the remanent ... of the magnet [2] For maximum power density, the product of the electric and magnetic loadings of the motor © 2002 by CRC Press LLC must be as high as possible A high electric loading necessitates...

Ngày tải lên: 23/10/2013, 16:15

... rotor temperature is higher, since there are no permanent magnets • There is a low rotor inertia and a high torque/inertia ratio • Extremely high speeds with a wide constant power region are possible ... is the requirement of two switches per phase This converter is especially suitable for highvoltage, high- power drives The split-capacitor converter shown in Fig 13.9b has only one switch per phase ... the motor must have an even number of phases Also, the power devices must be rated to withstand the full DC supply voltage The high cost of power semiconductor devices and the need to reduce the...

Ngày tải lên: 27/10/2013, 23:15

... than it is for induction motor drives The capital cost can be high, but the high efficiency can at least partially offset this in high- power applications For these reasons, the PMSM drive is expected ... many ways to use power converters to fix the voltage or current in a PMSM drive to desired set points Chapter details the modulation methods for inverter control Among them are voltage control ... omitted in this chapter In this section, the appropriate voltage and current commands are discussed These commands become the inputs to the power electronics converter with the given modulation strategy...

Ngày tải lên: 27/10/2013, 23:15

... OUTPUT VOLTAGE INPUT VOLTAGE -3 TIME IN MILLISECONDS FROM TRIGGER FIGURE 16.6 Standby power supply response to power disturbance Top trace: AC input; bottom trace: AC output (Courtesy of National Power ... installing a “minimum” battery, most short-term power outages can be supported For the long duration power outages, DC power generation can be used DC power generation generally requires only a connection ... power factor induced by many UPS installations With a DC generator, the induced power factor problem is not possible DC power generation has even grown into the lighting arena By using a DC power...

Ngày tải lên: 06/11/2013, 08:15

... transformer since high- voltage motors are available If the AC phase voltage is VN (rms value), then the DC link voltage will be V dc ≅ 3/ π 6V N and the maximum possible motor phase voltage will be ... motor voltage is positive and if α is between 0.5 and 1.0 the motor voltage becomes negative as illustrated in Fig 15.3 A very important advantage of this control scheme is that the motor voltage ... turn-on T4 turn-on T2 turn-on Motor voltage Vdc t Motor voltage t -Vdc (a) α < 0.5 FIGURE 15.3 (b) α > 0.5 DC chopper transistor control As a result of the high- frequency control, the motor current...

Ngày tải lên: 06/11/2013, 08:15

... into the supply The voltage across the winding when both switches are on is the supply voltage (neglecting the voltage drop across the switches) When the switches are off, the voltage across the ... circuited When Q1 is on, the phase voltage is +Vs (neglecting the voltage drop across the switch) When Q1 is off, the phase voltage is −Vs (neglecting the voltage drop across the diode) until ... the decay current is provided through the diode The voltage across the winding when the switch is on is the supply voltage, Vs (neglecting the voltage drop across the switch) The current in the...

Ngày tải lên: 06/11/2013, 08:15

... a voltage- controlled voltage source It takes the output of the soft limiter, which is a voltage with respect to ground, and creates a voltage with a floating reference potential for driving high- side ... cadence.com/ Rashid, M H., Power Electronics: Circuits, Devices, and Applications, Prentice-Hall, Englewood Cliffs, NJ, 1993 10 Rashid, M H., SPICE for Power Electronics and Electric Power, Prentice-Hall, ... that both the output voltage (10 V) and the average output current (10 V/15 Ω) are represented correctly in Fig 23.6 Since the input voltage is twice as high as the output voltage and the losses...

Ngày tải lên: 13/12/2013, 00:15

... was powered from a battery, he noticed that a transient voltage developed on the second coil and, later, this led him to develop a transformer Faraday concluded from his observations that voltage ... the magnetic flux changes at a rate of Wb/s in a single turn coil, the induced voltage is V 22.8 Inductance The induced voltage in a coil is proportional to the magnetic flux change that is shown ... surface bounded by a closed path induces a voltage inside a conductor loop This fundamental principle has important consequences for parasitic coupling in electronic hardware, such as a noisy circuit...

Ngày tải lên: 13/12/2013, 00:15

... unregulated DC voltage Then, a DC voltage regulator is used to provide power for the regulated high- voltage 270-V DC system A DC-DC converter and a DC-AC inverter connected to this system provide power ... will need highly reliable, fault-tolerant, autonomously controlled electrical power systems to deliver high- quality power from the sources to the loads The voltage level and form in which power is ... bidirectional power converter providing high- voltage DC to the main bus Moreover, in the motoring mode, i.e., cranking the engine, the high- voltage DC system via the bidirectional power converter...

Ngày tải lên: 13/12/2013, 00:15

... that both voltage magnitudes and line reactance will affect the reactive power If both voltage magnitudes are the same, i.e., flat voltage profile, each bus will send half of the reactive power absorbed ... shunt voltage source The second source, the series voltage source, is placed between the sending and the receiving buses Both voltage sources are modeled to inject voltages of fundamental power ... bus voltage magnitude The angle between the sending bus voltage and the injected shunt voltage, ϕSH (Eq 20.19), affects the real power flow in the shunt branch It can be used to control the power...

Ngày tải lên: 13/12/2013, 00:15

... multiple power lines and can be supplied with commodity quality power from several substations The connection of many QCCs will lead to the development of a new type of high- voltage power distribution ... among many kinds of power qualities, power interruption or power supply reliability is the most important function of unbundled power quality services A concept for real-time voltage regulation ... switches to reduce distribution losses, voltage sags, swells, flickers, interruptions, three-phase voltage unbalance, and voltage harmonics, by using advanced power electronics devices such as DSTATCOM,...

Ngày tải lên: 13/12/2013, 00:15

... as shown in Fig 18.3 If the voltage of a module drops below the voltage of other modules connected in parallel, it is possible for the current produced by the higher -voltage modules to flow in the ... terminal voltage becomes greater than the cell voltage as a result of the additional voltage drop across the internal battery resistance between the terminals and the cells Hence, if the terminal voltage ... output power vs cell temperature © 2002 by CRC Press LLC FIGURE 18.3 PV array showing modules with bypass and blocking diodes constant current up to the maximum cell voltage, and then constant voltage...

Ngày tải lên: 13/12/2013, 00:15