Fault current limiting in an electrical power network
First Claim
Patent Images
1. An electrical generator arrangement for an electrical power network, comprising:
- the electrical generator including a field coil arrangement which, in use, creates magnetic flux within the electrical generator arrangement;
a field current supply means, operable, in use, to control the field current in the field coil arrangement;
and a monitor means operable to monitor electrical power network conditions to detect the onset of a fault current;
the field current supply means being responsive, in use, to the onset of a fault current to reduce the generated current to the electrical power network, by control of the field current, wherein said field current supply means is operable to reverse the polarity of the control voltage applied to the field coil arrangement.
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Accused Products
Abstract
Generators 12a are for a distributed generation system. A control system 32a receives information about network faults 14a. In normal conditions, the control system 32a controls the field current in the field coils of the generator 12a, to maintain generator output voltage at the rated value. At the onset of fault conditions, the control system 32a changes the manner in which field current is controlled, in order to reduce the fault current put onto the network.
18 Citations
24 Claims
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1. An electrical generator arrangement for an electrical power network, comprising:
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the electrical generator including a field coil arrangement which, in use, creates magnetic flux within the electrical generator arrangement; a field current supply means, operable, in use, to control the field current in the field coil arrangement; and a monitor means operable to monitor electrical power network conditions to detect the onset of a fault current; the field current supply means being responsive, in use, to the onset of a fault current to reduce the generated current to the electrical power network, by control of the field current, wherein said field current supply means is operable to reverse the polarity of the control voltage applied to the field coil arrangement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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- 13. A method of electrical generation for an electrical power network comprising an electrical generator arrangement, the electrical generator arrangement including a field coil arrangement, in which the field coil arrangement is used to create magnetic flux within the electrical generator arrangement, the method comprising monitoring the electrical power network conditions to detect the onset of a fault current, and the controlling field current in the field coil arrangement in response to the onset of a fault current to reduce the generated electrical current to the electrical power network, wherein the polarity of the control voltage applied to the field coil arrangement is reversed in response to the onset of a fault current.
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21. An electrical power network comprising a plurality of electrical generators connected at appropriate points around the electrical power network, switchgear provided at various locations around the electrical power network to isolate a fault, each electrical generator including a field coil arrangement which, in use, creates magnetic flux within the electrical generator, each electrical generator including a field current supply means, operable, in use, to control the field current in the field coil arrangement, at least one of the electrical generators having a monitor means operable to monitor the electrical power network conditions to detect the onset of a fault current, the field current supply means being responsive, in use, to the onset of a fault current to reduce the generated current to the electrical power network, by control of the field current, wherein the field current supply means is operable to reverse the polarity of the control voltage applied to the field coil arrangement.
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22. A method of electrical generation for an electrical power network comprising a plurality of electrical generators connected at appropriate points around the electrical power network, switchgear provided at various locations around the electrical power network to isolate a fault, each electrical generator including a field coil arrangement which is used to create magnetic flux within the electrical generator arrangement, the method comprising monitoring the electrical power network conditions to detect the onset of a fault current, controlling the field current in the field coil arrangement of at least one of the electrical power network, including reversing the plurality of the control voltage applied to the field coil arrangement.
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23. An electrical generator arrangement for an electrical power network, comprising:
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the electrical generator including a field coil arrangement which, in use, creates magnetic flux within the electrical generator arrangement; a field current supply means, operable, in use, to control the field current in the field coil arrangement; and a monitor means operable to monitor electrical power network conditions to detect the onset of a fault current; the field current supply means being responsive, in use, to the onset of a fault current to reduce the generated current to the electrical power network, by control of the field current wherein the field current supply means includes a power electronic converter operable to control the field current, and wherein the power electronic converter includes a first diode device connected in parallel with the field coil, to be reversed biased relative to the field current, and first switch means operable to disconnect a common terminal of the field coil and the diode device, from the field current supply, whereby the common terminal is disconnected from the field current supply by opening the switch, allowing field current to re-circulate to the field coil, through the diode device.
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24. An electrical generator arrangement for an electrical power network, comprising:
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the electrical generator including a field coil arrangement which, in use, creates magnetic flux within the electrical generator arrangement; a field current supply means, operable, in use, to control the field current in the field coil arrangement; and a monitor means operable to monitor electrical power network conditions to detect the onset of a fault current; the field current supply means being responsive, in use, to the onset of a fault current to reduce the generated current to the electrical power network, by control of the field current wherein the field current supply means includes a power electronic converter operable to control the field current, and wherein the power electronic converter includes first and second switch means connected between respective first and second terminals of the field coil arrangement, and respective sides of the field current supply means, and further include first and second diode devices connected, respectively, between the supply side of the first switch and the second terminal of the coil, and between the supply side of the second switch and the first terminal of the coil, whereby the control voltage applied to the field coil arrangement is reversed by opening both switch means.
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Specification