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Voltage stabilisation system at extended power transmission line Voltage stabilisation system contains a transformer substation and an aerial transmission line with power supply branch lines, three independent voltage adders at each of the phase lines installed at the end of the last line, at that the voltage adder is made as a bridge circuit, two parallel interconnected branch lines, which consist of in-series accumulating LC delay line and bidirectional transistor-based commutator, in the bridge circuit diagonal there is an installed bidirectional triode thyristor, accumulating LC delay lines of the bridge circuit branches are connected to phase and zero wires respectively. |
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Device for control of three- and one-phase loads through power four-wire mains Invention is related to the field of electric engineering and, in particular, to control of pump units and can be used for alternate control of three- and one-phase loads through the power four-wire mains. The device contains at the power line input a protective device, a three-phase solenoid starter connected to the three-phase load connected at the line end and three wye-connected capacitors with an artificial earthing point are connected to the outputs of the starter; at the line beginning there is an ambient temperature sensor connected to a one-phase solenoid starter which contact is connected in parallel to one phase of the three-phase solenoid starter and at the line ending there is a heater switched on between a neutral wire and the artificial earthing point of three capacitors. |
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Device for detection of synchronous vibrations source Device includes a block of correlation devices for each generator, which includes the first and the second sensors that are connected to terminals of a synchronous generator, the first and the second correlation devices determining coefficients of mutual correlation of the effective value of voltage and reactive power, the first inputs of which are connected to the output of the first sensor, the second input of the first correlation device is connected to the output of the second sensor, a time delay unit the input of which is connected to the output of the second sensor as well, and the output is connected to the second input of the second correlation device, and an analysing device to the inputs of which there connected are outputs of the first and the second correlation devices of blocks of correlation devices of all the generators; besides, a signal at the output of the analysing device appears in case one of the synchronous generators is a source of synchronous vibrations in a power system or intercomputer vibrations in the group of generators of one thermal power plant. |
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Method for prevention of voltage collapse in power system Method consists in measurement of voltage, active and reactive power on buses of the station, control of available alarms from a stationary automatics of the generator "imitation of current overload of a rotor" and if they are available from all generators connected to buses of the station, then trip of load of the controlled power district is performed with accurate determination of unloading volume, which is calculated as per the following formula: Δ P 1 = B − B 2 − A C A , where A, B, C - design factors determined based on measurement of values of active power, reactive power and voltage on buses of the station. |
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Device for protection of equipment of power system Device to protect equipment of a power AC system comprises the first facility (15), configured with the possibility to measure frequency of current and voltage in at least one location (16) in the power system along an interconnection between two abstract electric machines of an equivalent two-machine system. The fourth facility (19) configured as capable of using the values of frequency of the measured current and voltage to determine whether there is power oscillation in the power system, and if the power oscillation has been determined, to determine whether the location (16) of measurement is at the side of the electric motor or the side of the generator of a potential electric centre of pole slipping along the interconnection. Besides, the electric centre is determined as the location, when the voltage becomes zero during pole slipping, and sending this information additionally into the third facility (20) for use in control for protection of equipment of the power system. |
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Device for power supply of long stator winding with several sections Device for power supply of a long stator winding (1) with several sections (2) contains a power supply source, a power line (6) connected to the power supply source, switches (3) of sections related to the power line (6) and having an output for connection with respective winding section used for compensation of reactive power notwithstanding power control and device for reactive power compensation in which impedance of the device can be set. |
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By way of preliminary analysis, a complex power pool grid is split into subsystems with minimum mutual impact. For each subsystem being controlled, based on the assumed splitting, one forms databases of sensibility factors and maximally allowed active power flows through links for different types of topology and accidental agitations. All the load lines and nodes of each subsystem being controlled are equipped with link agents and load agents. When any link is overloaded within the subsystem being controlled, such link agent, proceeding from information on the grid current topology and by way of linear optimisation tasks solution and by way of exchange of massages between link agents and load agents, calculates and implements the optimal control action vector. The algorithm keeps being executed until elimination of overloads with all the links within the subsystem being controlled or until any optimisation task being solved within the automation means operation cycle has a solution. |
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Damping of electro-magnetic oscillations in power supply systems Regulator for damping multiple electro-magnetic oscillations in power system (G) contains at least one electric value phasor measuring unit (PMU) receiving signals of these phasors including oscillation mode signals, at least, one regulator of power oscillation damper (POD) for receiving and attenuating signal of each oscillation mode, superposition device for receiving and summing attenuated signals and receiving control signal, feedback controller (H) for returning control signal to power flow control unit in power system (G), as well as device for separating oscillation modes in signals of these phasors, note that this means includes mode selection device and device for determination of deduction that has maximum norm in deduction matrix of selected mode. |
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Device to monitor efficiency of power usage in consumer power systems Device to monitor efficiency of power usage in consumer power systems comprising a set of current and voltage sensors connected to a switchboard, a permanent memory, outputs of metering converters are connected via the switchboard with a memory unit, the input-output of which is connected with a calculator, and its outputs are connected with an input of an electronic indicator, the inputs of which are connected also with outputs of the memory unit, the control device and the decision-making unit, inputs of the latter are connected with outputs of the memory unit, the calculator and the input-output of the control device, which with its inputs-outputs is also connected to the interface device, the memory unit and the sensor screen, at the same time the control device input is connected with the timer output. |
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Device consists of power direction control unit, starter unit of minimum frequency, first logic unit, first timer, first minimum voltage control unit, second logic unit, second timer, third logic unit, first actuator, second minimum voltage control unit, third timer and second actuator. First timer is minimum frequency protection output with control of power direction. Second timer is first stage output of minimum voltage protection with control of power direction. Third timer is second stage output of minimum voltage protection. First actuator switches off input section of switchgear that lost power supply and breaks field of synchronous motors at input section of switchgear that lost power supply. Second actuator switches off electric motors. |
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Method for fast-acting control of active-power flow During regulation of active-power flow between power system parts connected with power line (1), unbalance of active power on shaft (11) of generating unit is monitored, active-power flow over line (1) is changed by adjusting phase angle between voltage vectors in its end-points on buses (2) and (3) by means of controlled phase-slue device (12) included in line (1). Limited time interval is allocated, within which unbalance of active power is compensated by means of transferring electric energy accumulator (7) into discharging or charging mode when there is deficiency or excess of active power respectively, and power balance is restored by corresponding changing power generated by unit. |
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Thyristor-controlled series capacitor damping subsynchronous resonances Control unit (17) for a thyristor-controlled series capacitor connected to a electric power transmission line (12) comprises a control unit integrating a thyristor start control (18) and a generator of required voltage of the capacitor passing through zero depending on line current and voltage of the capacitor in response on a command signal, and a command control (19) which is used to generate the command signal for the thyristor start control, and accommodates a command damping control (24) comprising a damping unit at least on one discrete frequency. |
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Emergency control method of power of turbine generator of modular thermal power station (versions) As per the first version of the method there measured is output current and output voltage of turbine generator, active power is determined according to them, controlled and compared with reduction speed set points of active power and output voltage, and emergency imbalance of active power is calculated and compared to the set point. As per the second version of the method, the rotor speed is measured, rotor slip is determined relative to synchronous rotation speed and exceedance is controlled with the slide of the specified positive set point. As per the first and the second versions of the method, when set points are exceeded, there formed is pulse control impact on the turbine off-loading. As per the third version of the method, frequency of output voltage, rotor speed and flow of live steam before turbine is measured; negative rotor slip is determined relative to synchronous rotation speed, current power reserve of turbine is determined, exceedance is fixed with current turbine power reserve and with absolute value of rotor slip of the appropriate set points, and when frequency of output voltage is decreased to its set point, there formed is control impact on additional loading (forcing) of turbine, which is proportional to current reserve of its power. |
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Method and device for electrical transmission system Device is designed to reduce subsynchronous resonance in electrical transmission systems and includes facilities (16), (17) to define voltage components from the side of stator windings in generator (9) with one or more discrete frequencies and calculation means taking into account the results of the said calculations, voltage to be added to the specified voltage of stator windings to reduce subsyncronous resonance in electrical system and a circuit (20) configured so that calculated voltage can be added to the specified voltage of stator windings. |
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Invention is attributed to the field of electric engineering and can be used for improving dynamic stability of electric-power systems and for damping electromechanical vibrations of generator rotor. In the method for improving dynamic stability and vibrations damping, alternating current synchronous generator rotor speed is monitored and synchronous generator rotor speed is lowered after insertion disturbance into system up to the rotation rate of magnetic field by means of mechanical deceleration of mentioned generator rotor. Electromagnetic brake is mechanically linked with generator rotor and prime mover rotor via clutches, voltage on generator terminals and generator stator current is continuously measured by which parameters the generator electromagnetic power is determined. This power is compared with electromagnetic power value which existed before insertion of disturbance. When result of power comparison exceeds predefined value, control signal for electromagnetic brake switching on is generated. The value of decelerating torque is determined by difference between values of the measured electromagnetic power and the electromagnetic power which existed before disturbance insertion, and duration of decelerating torque application is determined by change in generator rotor speed. To do this the generator rotor speed after disturbance insertion is determined and compared with the value which existed before disturbance insertion. Electromagnetic brake is switched off when equality of current rotor speed and rotor speed in mode before disturbance is reached and when measured power is equal to the power which existed before disturbance insertion. |
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Method of revealing an asynchronous regime of electricity transmission The method allows calculate the coordinates of the end of the of impedance in vector in the system of coordinates received by turning in the complex plane of resistances on the calculated angle and transferring along the axes of real numbers on a prescribed value. Voltage in the electrical center of rocking is modeled and the diapason of the values of this voltage corresponding to the diapason of the angles of electric transmission substantially different from zero and including the value of 180o is controlled. The asynchronous regime is fixed at the output of the value of modeled voltage out of the set diapason if the symbol of voltage differs from the symbol of this voltage at the input into the prescribed diapason and the duration of passing through the established diapason prevails the prescribed value. The position of the electrical center of rocking is defined at the moment of changing of the symbol of the modeled voltage according to the outfit of the value of the coordinates of the end of the vector of impedance along the coordinate axis to one of the three prescribed diapasons. The number of cycles of the asynchronous mode is additionally calculated according to the moments of changing of the symbol of modeled voltage in the established diapason of values and operation of automatic equipment is formed at prevailing the number of the cycles of the prescribed setting. |
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Method of finding and liquidating of asynchronous mode in power system by automatic device Projection of total resistance onto axis is calculated, which projection is turned in complex plane of resistances for estimated angle relatively axis of coordinates. Projection of measured voltage to axis is calculated, which is turned in complex plane relatively current vector for the same estimated angle. First and second time derivatives are calculated from projection of voltage vector. Moment, when asynchronous mode origins, is registered on base of non-coincidence of sign of voltage vector with signs of its first and corrected second derivatives. Starting from that moment, time is measured and half-period of asynchronous mode is calculated through first derivative of projection of voltage vector. In case measured time exceeds time of half-period of async mode, reduced by preset value, availability of async mode is fixed to form effect of automatics for liquidation of the mode at favorable value of angle of electricity transmission. |
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Method of finding and liquidation of async mode in electric power by automatic control system Method can be used in aids of anti-alarm automatics of electric-power system. According to method, full resistance Z , calculated from local information (current and voltage in unit to be controlled) due to reduction its angle for correcting angle. Correcting angle is found during process through relation of increased reactive and active components of full resistance. Resistance is fixed till electric center of oscillations by using reactive component of transformed resistance Z. Active component of transformed resistance, which component is multiplied by electric transmission current, allows finding voltage Um in center. On base of voltage Um, angle δm of electric transmission is calculated on base trigonometric transform. From specified range of modeled voltage, range of angles of electric transmission is fixed beyond limits of working mode, in which mode the calculated angle more precisely corresponds to real one and async mode is revealed. By using angle of electric transmission and its derivatives and by defining location of center of oscillations in relation to unit to be controlled, threat, moment and fact of arise of async mode is fixed to form optimal action of automatic system. |
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Method for detecting asynchronous mode in power system Proposed method includes calculation of impedance vector as voltage-to-current vector ratio in point under check. Impedance vector projection onto axis turned in complex plane of impedances relative to imaginary axis through angle supplementing rated angle of equivalent power transmission impedance to 90 deg. is calculated. Resistance up to electrical center of oscillations is found by projection. Disposition of center of oscillations on line section under check is recorded when projection value occurs within specified range. Vector of voltage being measured onto axis turned in complex plane relative to power transmission current vector through same additional angle is calculated. Power transmission angle is calculated by voltage projection using simple trigonometric function. Asynchronous mode onset is detected by coincidence between signs of power transmission angle and those of its first and second time derivatives. Asynchronous mode hazard is recognized by excess of first derivative above admissible value calculated with aid of "angle-slip" boundary phase functions and parameters of original modes. |
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Method for increasing dynamic stability of synchronous electric machines Method for increasing dynamic stability of synchronous electric machines includes additional acceleration or braking of synchronous electric machines, performed by shifting of resulting magnetic flow of rotor simultaneously with mechanical turning of stator towards relative deviation of rotor in case of perturbation. |
Another patent 2513427.