Early Detection of Faults in Power Transmission Lines
AssigneeSmart Wires Inc.
InventorsHaroon Inam, Hamed Khalilinia
Life of this patent
Estimating the term…
Abstract
A modular power flow control system having early detection and reporting of transmission line faults is described. The response time for closing a bypass switch and reporting the fault is less than 200 microseconds for hard faults, longer for soft faults. Reprogramming of distance relays is not required. Transmission line faults are characterized using a fault detection sensor suite, normally including at least a current sensor such as a current transformer and a rate of current change sensor such as a Rogowski coil, and in some embodiments, a temperature sensor. Other embodiments are disclosed.
Claims28
A power flow control system for a power transmission line comprising:
- at least one impedance injection module coupled to the power transmission line, each impedance injection module including a current transformer, a Rogowski coil, a microprocessor and a memory;
- a bypass switch coupled around the at least one impedance injection module;
- wherein the memory contains instructions executable by the processor to process outputs from the current transformer and from the Rogowski coil to determine current and rate of change of current in the power transmission line;
- and,
- to use a mathematical equation comprising the variables of current and rate of change of current in the power transmission line to compare a calculated value against a pre-determined threshold value to characterize a fault that may have occurred, and to close the bypass switch if a fault has occurred.
A method for early detection and reporting of transmission line faults comprising:
- providing at least one impedance injection module;
- providing a bypass switch;
- providing at least one current sensor;
- providing a microprocessor;
- providing a memory containing instructions executable by the processor to process output from the at least one current sensor to determine current and rate of change of current in the transmission line during a fault;
- applying a mathematical equation comprising the variables current and rate of change of current in the transmission line to characterize a fault that may have occurred by comparing a calculated value against a pre-determined threshold value;
- deciding whether to close the bypass switch based on the comparison;
- deciding whether to report the fault based on the comparison;
- closing the bypass switch when decided to do so;
- and,
- reporting the fault to a support system when desired.
A method for detecting and responding to a fault current in a phase of a power transmission line comprising:
- providing a fault detection sensor suite having a plurality of detection instruments including at least a current transformer, a Rogowski coil and a temperature sensor;
- detecting at least one current characteristic by at least a first of the plurality of fault detection instruments;
- comparing the at least one current characteristic against a predetermined threshold value;
- closing a bypass switch when the at least one current characteristic exceeds the predetermined threshold value.
The method of claim 21 wherein when the bypass switch is closed, wirelessly reporting the occurrence of the fault current to a support system.
A method for detecting and reporting a fault in a phase of a power transmission line comprising:
- providing a fault detection sensor suite having a plurality of fault detection instruments including at least a current transformer detecting current in the power transmission line, a Rogowski coil detecting a rate of change of current in the power transmission line, and a temperature sensor;
- combining parameters detected by the plurality of fault detection instruments according to a mathematical equation;
- comparing the result of combining parameters detected by the plurality of fault detection instruments to a predetermined threshold value;
- when the result of combining parameters detected by the plurality of fault detection instruments exceeds the predetermined threshold value, providing a bypass switch closure signal that will cause a bypass switch to close, and causing the reporting of the detection of a fault in the phase of a power transmission line.
A power flow control system for attaching to a power transmission line comprising:
- at least one impedance injection module for connecting to the power transmission line;
- a bypass switch for connecting to the power transmission line to bypass the at least one impedance module when the bypass switch is closed;
- a current transformer for sensing current in the power transmission line;
- a Rogowski coil for sensing the rate of change of current in the power transmission line;
- a microprocessor;
- a memory;
- wherein the memory contains instructions executable by the processor to combine outputs from the current transformer and from the Rogowski coil in a predetermined manner and to compare the combination with a pre-determined threshold value to characterize a fault that may have occurred, and to close the bypass switch if the comparison is indicative of a fault current.
A method for detecting and responding to a fault current in a power transmission line comprising:
- providing a Rogowski coil around the power transmission line for sensing at least one characteristic of current in the power line;
- comparing the at least one characteristic of current in the power line with a predetermined threshold value;
- closing a bypass switch when the at least one characteristic of current in the power line exceeds the predetermined threshold value.
Dependencies are inferred from the claim text.