System for regulating the active power transferred into and out of direct voltage network by multiple power stations
First Claim
1. A system for transmitting power comprising:
- a direct voltage network;
at least two alternating voltage networks;
a first power station connecting one of said alternating voltage networks to said direct voltage network including;
(i) a VSC converter for bi-directionally transferring power between said direct voltage network and one of said alternating voltage networks,(ii) control means for selectively controlling said VSC converter so that either a constant value of direct voltage is maintained on said direct voltage network, or a constant current is maintained between said alternating voltage network and said direct voltage network,(iii) means for comparing the voltage on said direct voltage network with a nominal value, and for controlling said VSC converter to maintain said voltage on said direct voltage network at said nominal value, and(iv) means for switching said means for controlling into a current controlling mode if said VSC converter fails to restore said direct voltage network to said nominal value of direct voltage,a second power station connecting said direct voltage network to a remaining of said alternating voltage networks including,(i) a VSC converter for bi-directionally transferring power between said direct voltage network and said remaining alternating voltage network,(ii) means for comparing said direct voltage on said direct voltage network to a nominal voltage value,(iii) control means for selectively controlling said second power station VSC converter so that either a constant value of direct voltage is maintained on said direct voltage network, or a constant current is maintained between said direct voltage network and said remaining alternating voltage network; and
(iv) switching means connected to said means for selectively controlling said second power station VSC converter for switching said VSC converter from a current controlling mode to a voltage controlling mode when said means for comparing indicates that said first power station has failed to maintain said direct voltage at said nominal voltage value.
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Accused Products
Abstract
A system for transmitting power over a direct voltage network. A first power station connects one alternating voltage network to the direct voltage network. The first power station includes a converter for bidirectionally transferring power between the direct voltage network and the alternating voltage network. The converter maintains constant value of voltage on the network, or operates in a second alternative mode of controlling constant current between the alternating voltage network and the direct voltage network. When the voltage on the direct voltage network drops below a reference value, a second power station connected to the direct voltage network and to a remaining alternating voltage network takes over the voltage regulation function. The second power station prior to taking over the voltage regulating friction was in a current regulating function. In this way, when the first station reaches its limits of voltage regulation, the second station is enabled to take over the voltage regulating function switching out of a current regulating function.
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Citations
13 Claims
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1. A system for transmitting power comprising:
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a direct voltage network; at least two alternating voltage networks; a first power station connecting one of said alternating voltage networks to said direct voltage network including; (i) a VSC converter for bi-directionally transferring power between said direct voltage network and one of said alternating voltage networks, (ii) control means for selectively controlling said VSC converter so that either a constant value of direct voltage is maintained on said direct voltage network, or a constant current is maintained between said alternating voltage network and said direct voltage network, (iii) means for comparing the voltage on said direct voltage network with a nominal value, and for controlling said VSC converter to maintain said voltage on said direct voltage network at said nominal value, and (iv) means for switching said means for controlling into a current controlling mode if said VSC converter fails to restore said direct voltage network to said nominal value of direct voltage, a second power station connecting said direct voltage network to a remaining of said alternating voltage networks including, (i) a VSC converter for bi-directionally transferring power between said direct voltage network and said remaining alternating voltage network, (ii) means for comparing said direct voltage on said direct voltage network to a nominal voltage value, (iii) control means for selectively controlling said second power station VSC converter so that either a constant value of direct voltage is maintained on said direct voltage network, or a constant current is maintained between said direct voltage network and said remaining alternating voltage network; and (iv) switching means connected to said means for selectively controlling said second power station VSC converter for switching said VSC converter from a current controlling mode to a voltage controlling mode when said means for comparing indicates that said first power station has failed to maintain said direct voltage at said nominal voltage value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification