Power distribution systems
First Claim
1. A power distribution system comprising:
- a first service distribution system including;
a first switchboard that includes protective switchgear with contacts, anda first dc distribution busbar connected to the first switchboard for carrying a distribution voltage and a distribution current;
a first power generation system including a first power source and a first power converter for supplying power to the first service distribution system, the first power source being connected to the first switchboard by the first power converter;
a zonal power distribution sub-system including;
a zonal power supply unit for supplying power to a first electrical load, anda zonal energy store connected to the first switchboard by a second power converter and to the zonal power supply unit, the zonal energy store supplying power to the zonal power supply unit; and
a second electrical load connected to the first switchboard by a third power converter;
wherein the first power converter of the first power generation system is regulated according to a power source foldback and stabilizing characteristic and a power source starting sequence, and wherein the third power converter that connects the second electrical load to the first switchboard is regulated according to a load shedding and stabilizing characteristic;
wherein the contacts of the protective switchgear are made to open only when the distribution voltage and the distribution current have been reduced to acceptable levels by the interaction of the power source foldback and stabilizing characteristic with one of (a) a fault that causes an excessively low impedance to be connected across the distribution voltage, (b) an overriding inter-tripping command that is automatically generated within the power distribution system, (c) an overriding inter-tripping command that is manually generated within the power distribution system, and (d) an overriding inter-tripping command that is generated remotely; and
wherein the contacts of the protective switchgear are made to close only when the polarity of the voltage across the contacts is such that any transient or inrush currents will be restricted by one of (a) the power source foldback and stabilizing characteristic and the power source starting sequence, and (b) the load shedding and stabilizing characteristic; and
wherein the power source foldback and stabilizing characteristic includes regulating the output voltage and the output current of the first power converter of the first power generation system such that;
(i) current flow is uni-directional;
(ii) a steady state output voltage is the sum of an off load bus voltage setpoint and a steady state droop component that is proportional to load current such that the steady state output voltage is in accordance with a steady state load line;
(iii) transient load current variations about a steady state loading point cause the output voltage to follow a transient load line whose gradient is less than the gradient of the steady state load line;
(iv) steady state current is limited to a particular level;
(v) if load current transiently exceeds the steady state current limit and approaches, but does not exceed, a particular transient current limit level, the output voltage will transiently reduce with respect to the steady state load line and will recover to the steady state load line when the steady state current reduces below the steady state current limit;
(vi) if load current continuously exceeds the steady state current limit, or exceeds the particular transient current limit level, foldback is applied such that the output voltage and the output current reduce to zero or approximately zero according to a regenerative process, and output voltage and output current remain at zero or approximately zero until load impedance has increased beyond a particular level; and
(vii) if load impedance increases beyond the particular level, then load voltage initially partially recovers and then is ramped up to a desired operating point.
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Accused Products
Abstract
A power distribution system that can be used in naval ships and submarines includes a first power generation system including at least one power source for supplying power to a first service distribution system that includes at least one dc distribution busbar for carrying a distribution voltage and a distribution current and at least one switchboard that includes protective switchgear with contacts. A zonal power distribution sub-system includes a zonal power supply unit for supplying power to at least one electrical load and a zonal energy store connected to the at least one switchboard of the first service distribution system for supplying power to the zonal power supply unit. The at least one power source is regulated according to a power source foldback and stabilizing characteristic and a power source starting characteristic. The at least one electrical load is regulated according to a load shedding and stabilizing characteristic.
18 Citations
30 Claims
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1. A power distribution system comprising:
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a first service distribution system including; a first switchboard that includes protective switchgear with contacts, and a first dc distribution busbar connected to the first switchboard for carrying a distribution voltage and a distribution current; a first power generation system including a first power source and a first power converter for supplying power to the first service distribution system, the first power source being connected to the first switchboard by the first power converter; a zonal power distribution sub-system including; a zonal power supply unit for supplying power to a first electrical load, and a zonal energy store connected to the first switchboard by a second power converter and to the zonal power supply unit, the zonal energy store supplying power to the zonal power supply unit; and a second electrical load connected to the first switchboard by a third power converter; wherein the first power converter of the first power generation system is regulated according to a power source foldback and stabilizing characteristic and a power source starting sequence, and wherein the third power converter that connects the second electrical load to the first switchboard is regulated according to a load shedding and stabilizing characteristic; wherein the contacts of the protective switchgear are made to open only when the distribution voltage and the distribution current have been reduced to acceptable levels by the interaction of the power source foldback and stabilizing characteristic with one of (a) a fault that causes an excessively low impedance to be connected across the distribution voltage, (b) an overriding inter-tripping command that is automatically generated within the power distribution system, (c) an overriding inter-tripping command that is manually generated within the power distribution system, and (d) an overriding inter-tripping command that is generated remotely; and wherein the contacts of the protective switchgear are made to close only when the polarity of the voltage across the contacts is such that any transient or inrush currents will be restricted by one of (a) the power source foldback and stabilizing characteristic and the power source starting sequence, and (b) the load shedding and stabilizing characteristic; and wherein the power source foldback and stabilizing characteristic includes regulating the output voltage and the output current of the first power converter of the first power generation system such that; (i) current flow is uni-directional; (ii) a steady state output voltage is the sum of an off load bus voltage setpoint and a steady state droop component that is proportional to load current such that the steady state output voltage is in accordance with a steady state load line; (iii) transient load current variations about a steady state loading point cause the output voltage to follow a transient load line whose gradient is less than the gradient of the steady state load line; (iv) steady state current is limited to a particular level; (v) if load current transiently exceeds the steady state current limit and approaches, but does not exceed, a particular transient current limit level, the output voltage will transiently reduce with respect to the steady state load line and will recover to the steady state load line when the steady state current reduces below the steady state current limit; (vi) if load current continuously exceeds the steady state current limit, or exceeds the particular transient current limit level, foldback is applied such that the output voltage and the output current reduce to zero or approximately zero according to a regenerative process, and output voltage and output current remain at zero or approximately zero until load impedance has increased beyond a particular level; and (vii) if load impedance increases beyond the particular level, then load voltage initially partially recovers and then is ramped up to a desired operating point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of controlling a power distribution system comprising:
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a first service distribution system including; a first switchboard that includes protective switchgear with contacts, and a first dc distribution busbar connected to the first switchboard for carrying a distribution voltage and a distribution current; a first power generation system including a first power source and a first power converter for supplying power to the first service distribution system, the first power source being connected to the first switchboard by the first power converter; a zonal power distribution sub-system including; a zonal power supply unit for supplying power to a first electrical load, and a zonal energy store connected to the first switchboard by a second power converter and to the zonal power supply unit, the zonal energy store supplying power to the zonal power supply unit; and a second electrical load connected to the first switchboard by a third power converter; the method comprising the steps of; regulating the first power converter of the first power generation system according to a power source foldback and stabilizing characteristic and a power source starting sequence; regulating the third power converter that connects the second electrical load to the first switchboard according to a load shedding and stabilizing characteristic; wherein the contacts of the protective switchgear are made to open only when the distribution voltage and the distribution current have been reduced to acceptable levels by the interaction of the power source foldback and stabilizing characteristic with one of (a) a fault that causes an excessively low impedance to be connected across the distribution voltage, (b) an overriding inter-tripping command that is automatically generated within the power distribution system, (c) an overriding inter-tripping command that is manually generated within the power distribution system, and (d) an overriding inter-tripping command that is generated remotely; and wherein the contacts of the protective switchgear are made to close only when the polarity of the voltage across the contacts is such that any transient or inrush currents will be restricted by one of (a) the power source foldback and stabilizing characteristic and the power source starting sequence, and (b) the load shedding and stabilizing characteristic; and wherein the power source foldback and stabilizing characteristic includes the steps of regulating the output voltage and the output current of the first power converter of the first power generation system such that; (i) current flow is uni-directional; (ii) a steady state output voltage is the sum of an off load bus voltage setpoint and a steady state droop component that is proportional to load current such that the steady state output voltage is in accordance with a steady state load line; (iii) transient load current variations about a steady state loading point cause the output voltage to follow a transient load line whose gradient is less than the gradient of the steady state load line; (iv) steady state current is limited to a particular level; (v) if load current transiently exceeds the steady state current limit and approaches, but does not exceed, a particular transient current limit level, the output voltage will transiently reduce with respect to the steady state load line and will recover to the steady state load line when the steady state current reduces below the steady state current limit; (vi) if load current continuously exceeds the steady state current limit, or exceeds the particular transient current limit level, foldback is applied such that the output voltage and the output current reduce to zero or approximately zero according to a regenerative process, and output voltage and output current remain at zero or approximately zero until load impedance has increased beyond a particular level; and (vii) if load impedance increases beyond the particular level, then load voltage initially partially recovers and then is ramped up to a desired operating point. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method of controlling a power distribution system comprising:
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a first service distribution system including; a first switchboard that includes protective switchgear with contacts, and a first dc distribution busbar connected to the first switchboard for carrying a distribution voltage and a distribution current; a first power generation system including a first power source and a first power converter for supplying power to the first service distribution system, the first power source being connected to the first switchboard by the first power converter; a zonal power distribution sub-system including; a zonal power supply unit for supplying power to a first electrical load, and a zonal energy store connected to the first switchboard by a second power converter and to the zonal power supply unit, the zonal energy store supplying power to the zonal power supply unit; and a second electrical load connected to the first switchboard by a third power converter; the method comprising the steps of; regulating the first power converter of the first power generation system according to a power source foldback and stabilizing characteristic and a power source starting sequence; regulating the third power converter that connects the second electrical load to the first switchboard according to a load shedding and stabilizing characteristic; wherein the contacts of the protective switchgear are made to open only when the distribution voltage and the distribution current have been reduced to acceptable levels by the interaction of the power source foldback and stabilizing characteristic with one of (a) a fault that causes an excessively low impedance to be connected across the distribution voltage, (b) an overriding inter-tripping command that is automatically generated within the power distribution system, (c) an overriding inter-tripping command that is manually generated within the power distribution system, and (d) an overriding inter-tripping command that is generated remotely; and wherein the contacts of the protective switchgear are made to close only when the polarity of the voltage across the contacts is such that any transient or inrush currents will be restricted by one of (a) the power source foldback and stabilizing characteristic and the power source starting sequence, and (b) the load shedding and stabilizing characteristic; and wherein the power source foldback and stabilizing characteristic includes the steps of regulating the output voltage and the output current of the first power converter of the first power generation system such that; (i) current flow is uni-directional; (ii) a steady state output voltage is the sum of an off load bus voltage setpoint and a steady state droop component that is proportional to load current such that the steady state output voltage is in accordance with a steady state load line; (iii) transient load current variations about a steady state loading point cause the output voltage to follow a transient load line whose gradient is less than the gradient of the steady state load line; (iv) steady state current is limited to a particular level; (v) if load current transiently exceeds the steady state current limit and approaches, but does not exceed, a particular transient current limit level, the output voltage will transiently reduce with respect to the steady state load line and will recover to the steady state load line when the steady state current reduces below the steady state current limit; (vi) if load current continuously exceeds the steady state current limit, or exceeds the particular transient current limit level, foldback is applied such that the output voltage and the output current reduce to zero or approximately zero according to a regenerative process, and output voltage and output current remain at zero or approximately zero until load impedance has increased beyond a particular level; and (vii) if load impedance increases beyond the particular level, then load voltage initially partially recovers and then is ramped up to a desired operating point; wherein the power source starting sequence includes the steps of; (i) initially setting the off load bus voltage setpoint of the power source foldback and stabilizing characteristic to zero; (ii) detecting a need for the first power source of the first power generation system to start supply power by sensing one of (a) the presence of distribution voltage resulting from the closure of the first switchboard, (b) an overriding start command that is automatically generated within the power distribution system, (c) an overriding start command that is manually generated within the power distribution system, and (d) an overriding start command that is generated remotely; (iii) upon detecting a need to start supplying power, starting the first power source of the first power generation system and ramping up the off load bus voltage setpoint of the power source foldback and stabilizing characteristic to a desired operating point; and wherein the load shedding and stabilizing characteristic includes the step of regulating the load current according to a current limit such that load current is permitted to attain any desired value but is always subject to overriding regulator functions that; (i) limit the rate of change of load current resulting from distribution voltage transients; and (ii) oppose any action that would otherwise cause load current to exceed the current limit; and where the current limit; (i) is adjustable up to and not exceeding a particular value of current limit; (ii) is held constant when supply voltage exceeds a load shed threshold; (iii) is progressively reduced as the supply voltage is reduced below the load shed threshold and at all levels of supply voltage above an absolute minimum loaded voltage; (iv) is set to zero when the supply voltage is less than the absolute minimum loaded voltage; (v) is set to zero when the supply voltage increases from a value less than the absolute minimum loaded voltage and up to a particular value; and (vi) is progressively increased as the supply voltage is increased.
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Specification