Method and device for control of a series-compensated converter station
First Claim
1. A method for control in rectifier operation of a series-compensated converter station included in an installation for transmission of high-voltage direct current, said converter station comprising a converter (SR1) which is controlled by control equipment (CE1) and which is connected to a three-phase alternating-voltage network (N1) by means of series connected capacitors, the control equipment generating an ordered value (AOL) of a control angle (α
- ) for valves (V1-V6) included in the converter, said ordered value being limited to a lower limiting value, wherein a first control angle calculating value (AFIRL) is continuously calculated according to a predetermined relationship (H'"'"'1, H'"'"'2), which at least approximately expresses a relationship according to which the control angle, at a firing voltage (Ufir) for the valves equal to a preselected value (Uvref), is a function (G'"'"'0) of a current (Id1) and of a voltage (Unl) in the converter station, and that the lower limiting value is formed in dependence on said first control angle calculating value.
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Accused Products
Abstract
Control equipment (CE1) generates an ordered value (AOL) of a control angle (α) 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 )
9 Citations
20 Claims
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1. A method for control in rectifier operation of a series-compensated converter station included in an installation for transmission of high-voltage direct current, said converter station comprising a converter (SR1) which is controlled by control equipment (CE1) and which is connected to a three-phase alternating-voltage network (N1) by means of series connected capacitors, the control equipment generating an ordered value (AOL) of a control angle (α
- ) for valves (V1-V6) included in the converter, said ordered value being limited to a lower limiting value, wherein a first control angle calculating value (AFIRL) is continuously calculated according to a predetermined relationship (H'"'"'1, H'"'"'2), which at least approximately expresses a relationship according to which the control angle, at a firing voltage (Ufir) for the valves equal to a preselected value (Uvref), is a function (G'"'"'0) of a current (Id1) and of a voltage (Unl) in the converter station, and that the lower limiting value is formed in dependence on said first control angle calculating value.
- View Dependent Claims (2, 3, 4, 5, 12)
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6. A device for control in rectifier operation of a series-compensated converter station included in an installation for transmission of high-voltage direct current, said converter station comprising a converter (SR1) which is controlled by control equipment (CE1) and which is connected to a three-phase alternating-voltage network (N1) by means of series connected capacitors, the control equipment comprising a control-angle unit (CAC) for generating an ordered value (AOL) of a control angle (α
- ) for valves (V1-V6) included in the converter, said ordered value being limited to a lower limiting value in dependence on a first limiting signal (AMINL), wherein the control equipment comprises a first calculating unit (AFCAL) which is supplied with a measured value (ID1) of a current (Id1) continuously sensed in the converter and a voltage value (UDI01), formed in dependence on a measured value (UN1) of a voltage (Un1) continuously sensed in the converter station, and which continuously, in dependence on the measured value of said sensed current and said voltage value, calculates a first control angle calculating value (AFIRL) according to a relationship (H'"'"'1, H'"'"'2), which at least approximately expresses a relationship according to which the control angle, at a firing voltage (Ufir) for the valves equal to a preselected value (Uvref), is a function (G'"'"'0) of said sensed current (Id1) and said sensed voltage (Un1), and that the first calculating unit forms the first limiting signal in dependence on said first control angle calculating value.
- View Dependent Claims (7, 8, 9, 10)
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11. A method for controlling rectifier operation of a series-compensated converter station in an installation for transmission of high-voltage direct current, said converter sation includes a converter (SR1) having valves with a firing voltage (Ufir) equal to a preselected reference voltage (UVref), said converter being connected to a three-phase alternating-voltage network (N1) by means of series connected capacitors, and control equipment for controlling the converter, the control equipment generating an ordered value (AOL) of a control angle (α
- ) for the valves (V1-V6), said ordered value being limited to a lower limiting value comprising the steps of;
continuously calculating a first control angle calculating value (AFIRL) according to a predetermined relationship (H'"'"'1, H'"'"'2), approximately expressing a relationship wherein the control angle is a function (G'"'"'0) of a current (Id1) and of a voltage (Un1) in the converter station when the firing voltage (Ufir) equals the preselected value (Uvref); and forming the lower limiting value in dependence on said first control angle calculating value. - View Dependent Claims (13, 14, 15)
- ) for the valves (V1-V6), said ordered value being limited to a lower limiting value comprising the steps of;
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16. Apparatus for controlling rectifier operation of a series-compensated converter station adapted to be connected to a three-phase alternating-voltage network (N1) in an installation for transmission of high-voltage direct current, said converter station including:
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a converter (SR1) having values operable at a firing voltage (Ufir) equal to a preselected reference value (Uvref); series connected capacitors for connecting the converter to the network; control equipment for controlling the converter including; a control-angle unit (CAC) for generating an ordered value (AOL) of a control angle (α
) for the valves (V1-V6), said ordered value being limited to a lower limiting value in dependence on a first limiting signal (AMINL);means for continuously sensing a current (Id1) and a voltage (Un1); means for measuring a value (ID1) of said current, and a corresponding voltage value (UN1); means for producing a voltage (UDI01) as a function of the voltage value (UN1); a first calculating unit (AFCAL) responsive to the measured value (UDI01) and the voltage (UDI01) for continuously calculating a control angle calculating value (AFIRL) according to a predetermined relationship (H'"'"'1, H'"'"'2), approximately expressing a relationship wherein the control angle is a function (G'"'"'0) of said sensed current (Id1) and said sensed voltage (Un1), when the firing voltage (Ufir) for the valves equals the preselected value (Uvref), said calculating unit producing the first limiting signal in dependence on said first control angle calculating value. - View Dependent Claims (17, 18, 19, 20)
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Specification