摘要:
Control equipment (CE2) generates an ordered value (AOL) of a control angle (.alpha.) in dependence on a limiting signal (AMAXL), capable of being influenced, for a converter included in a series-compensated converter station. A calculating value (AMARG) of a control angle is calculated continuously according to a predetermined relationship (M0, M1, M2, M3) which at least approximately resembles a relationship according to which, at a commutating margin (.gamma..sub.m) equal to a preselected value (.gamma..sub.p), said control angle is a function (F0) of a current (Id2) and a voltage (Un2) in the converter station and the limiting signal is formed in dependence on the calculating value.
摘要:
An installation for transmission of electric power by means of high-voltage direct current has two converters (SRI, SRII), each of which is connected to an alternating-voltage network (NI, NII) and which are connected to each other through a dc connection (L). One converter (SRI) is controlled as a rectifier and another converter (SRII) is controlled as an inverter. One converter (SRI) is current-controlling and another converter (SRII) is voltage-controlling. The installation has means (VARC.sub.rect) adapted, at such a change of the control angle (.alpha..sub.rect) of the current-controlling converter (SRI) that the angle reaches a limit of a predetermined interval (.alpha..sub.max nom rect -.alpha..sub.min nom rect) to control, by means of the voltage-controlling converter (SRII), the direct voltage (Ud) of the transmission in such a way that said change is limited.
摘要翻译:通过高压直流电传输电力的设备有两个转换器(SRI,SRII),每个转换器连接到一个交流电压网络(NI,NII),并通过一个直流 连接(L)。 一个转换器(SRI)被控制为整流器,另一个转换器(SRII)被控制为逆变器。 一个转换器(SRI)是电流控制,另一个转换器(SRII)是电压控制的。 安装具有在电流控制转换器(SRI)的角度达到预定间隔的极限(αmax nom rect-αmin nom rect)的控制角(α1)的这种改变的情况下适用的装置(VARCrect) )通过电压控制转换器(SRII)来控制变速器的直流电压(Ud),使得所述变化受到限制。
摘要:
Control equipment (CE1) generates an ordered value (AOL) of a control angle (.alpha.) in dependence on a limiting signal (AMINL, AMAXL), capable of being influenced, for a converter included in a series-compensated converter station. A calculating value (AFIRL) of a control angle is calculated continuously according to a predetermined relationship (H'1, H'2) which at least approximately imitates a relationship according to which, at a firing voltage (Ufir) for the valves of the converter equal to a preselected value (Uvref), said control angle is a function (G'0) of a current (Id1) and a voltage (Un1) in the converter station and the limiting signal is formed in dependence on the calculating value. (FIG. 5 )
摘要:
An installation for transmission of high-voltage direct current comprises a first and a second converter (SR1, SR2, respectively), each one controlled by a separate piece of control equipment (CE1, CE2, respectively). Each one of the pieces of control equipment comprises a current controller (CC). The current controller of the second converter is supplied with a second current reference value (IOL2) and a current margin (IOM). The control equipment of the second converter comprises a function-forming member (11), which in dependence on an applied measured value (UD) of the direct voltage forms the current margin such that, when the direct voltage exceeds a first preselected voltage level (Udf), it assumes a first value (IOMf) and, when the direct voltage is lower than the first voltage level, it assumes a second value (IOMs), the magnitude of the second value being greater than the magnitude of the first value.
摘要:
A series-compensated converter station in an installation for transmission of high-voltage direct current is connected to an alternating-voltage network (N) with three phases (A, B, C, respectively). The converter station comprises at least two direct-voltage series-connected six-pulse converter bridges (SR1, SR2, respectively), a three-phase transformer coupling with two secondary windings (SW1, SW2, respectively), and a star-connected primary winding (PW) with a neutral point (NP) connected to ground as well as a series capacitor unit (CN) for each one of the three phases. Each one of the converter bridges is connected to a respective secondary winding and the primary winding is connected to the alternating-voltage network via the series-capacitor units. The transformer coupling exhibits a high impedance to zero-sequence currents through the primary winding of the transformer coupling.
摘要:
A series-compensated converter station included in an installation for transmission of high-voltage direct current comprises a converter (SR1, SR2) with at least one 6-pulse bridge (BR). Via series capacitors (SCR, SCS, SCT) the 6-pulse bridge is connected to a three-phase alternating-voltage network (N1, N2) with a fundamental frequency (f.sub.01, f.sub.02). Control equipment (CE1, CE2) generates an ordered value (AOL) of a control angle (.alpha.) for valves (V1-V6) included in the 6-pulse bridge in dependence on a limiting signal (AMAXL) capable of being influenced. An amplitude signal (AMPL) is formed which corresponds to the amplitude (C.sub.1) for a component (C.sub.1 cos(2.pi.f.sub.0 t+.phi..sub.1)) of the fundamental frequency in the direct voltage (Udb) of the 6-pulse bridge and a compensating signal (ACOMP) is continuously calculated in dependence on a sensed voltage (Un1, Un2) at the converter station and on the amplitude signal. The limiting signal is formed in dependence on the compensating signal for the purpose of maintaining the commutating margin (.gamma..sub.m) for the valves equal to at least the preselected value (.gamma..sub.p) in case of unbalance between the voltages (UCR, UCS, UCT) of the series capacitors. (FIG. 6)
摘要:
A method of controlling a magnitude of an electrical parameter in a power system via a high voltage electron tube. The method includes the steps of measuring the magnitude of the electrical parameter; generating a control signal based on the magnitude of the electrical parameter and on a reference magnitude of the electrical parameter; and switching the high voltage electron tube via the control signal such that the reference magnitude of the electrical parameter is essentially obtained. A control arrangement and a power system is also presented.
摘要:
A thyristor controlled series capacitor module including a capacitor connectable in series with a power line, a thyristor valve connected in parallel with the capacitor, a breaker connected in parallel with the thyristor valve, and an inductor. By providing a simplified breaker arrangement, the number of components is reduced.
摘要:
In a computer system the instruction decoding unit for translating program instructions to microcode instructions operates dynamically. Thus the unit receives state signals indicating the state of the computer, such as a trace enabling signal, influencing the translation process in the instruction decoding unit. These state signals are added to the operation code of the program instruction to be decoded, the operation code of the program instruction thus being extended and used as input to a translating table, the extended operation code of the program instruction being taken as an address of a field in the table. The addresses and thus the contents of the fields addressed for the same operation code of a program instruction can then be different for different values of the state signals. Thus generally, the state signals cause the instruction decoder to change its translating algorithm so that the decoder can decode an operation code differently depending on the state which the signals adopt. The dynamic decoding can for a trace enabling signal be used for switching on and off a trace function. In the normal case, when tracing is not desired, no microinstructions supporting the trace function have to executed and thereby the performance and in particular the speed of the computer system will be increased.
摘要:
A direct electrostatic printing device and method for printing an image to an information carrier with improved harmonization of the printed density from a plurality of rows of apertures. The harmonization of the printed density from apertures from different rows is accomplished by an improved method of controlling the amount of pigment particles transported through the apertures of each row. The method takes into account which row the aperture belongs to and how the rows are positioned in relationship to the pigment particle feed.