Patent application number | Description | Published |
20110085273 | Circuit Breaker With Improved Re-Closing Functionality - A circuit breaker for protecting a power line. The circuit breaker includes a control unit and a circuit breaking element disconnecting the power line from a power source. The control unit detects a fault on the power line, opens the circuit breaking element, which opening starts a disconnection time interval, injects a test signal into the power line, measures a response, determines an impedance of the power line from the response, analyses the impedance during the time interval based on comparing the impedance with a reference threshold, determines a permanent or a temporary fault based on the analysed impedance, re-closes the circuit breaking element after the time interval if the fault is temporary and keeps the circuit breaking element open after the time interval if the fault is permanent. | 04-14-2011 |
20110188159 | METHOD AND DEVICE FOR SUPERVISING SECONDARY CIRCUIT OF INSTRUMENT TRANSFORMER IN POWER SYSTEM - A method and a protection IED for supervising a secondary circuit of an instrument transformer in a power system are disclosed. The instrument transformer is connected to a power system component. The method includes: detecting, by a protection IED which is connected to the secondary circuit of the instrument transformer and protects the power system component, disturbances in a signal from the instrument transformer; and determining whether a failure occurs in the secondary circuit of the instrument transformer, according to both a disturbance detection result from the protection IED and another disturbance detection result from at least one of other protection IEDs. The other protection IEDs include protection IEDs which are connected to other secondary circuits of the instrument transformer or to secondary circuits of another instrument transformer connected to the power system component, and protection IEDs which are connected to other instrument transformers connected to other power system components connected to the same busbar as the power system component is connected to. The secondary circuit supervision solutions provide more reliable and sensitive performance and need very small amount of information to be collected. | 08-04-2011 |
20120089262 | INTELLIGENT PROCESS INTERFACE AND SUBSTATION AUTOMATION SYSTEM - This specification discloses an intelligent and digitalized process level interface which is referred to herein as an Intelligent Process Interface (IPI). The input of the IPI includes both analog and digital channels and therefore the IPI can be used for substations in transition or retrofit stages with both conventional and non-conventional primary devices. The IPI acts not only as a digitalized interface, but also as an intelligent supervisory and control unit for switching functions. The architecture of the IPI is flexible and allows for the functionality to be distributed to several devices. | 04-12-2012 |
20130077204 | BREAKER FAILURE PROTECTION OF HVDC CIRCUIT BREAKERS - A breaker failure protection system for a high voltage direct current, HVDC, circuit breaker is provided. The circuit breaker is arranged for interrupting a DC circuit upon reception of a trip signal. The protection system includes a current sensor, at least one inductor, and a breaker failure detection unit. The current sensor is arranged for measuring a current I(t) through the DC circuit. The at least one inductor is connected in series with the DC circuit. The breaker failure detection unit is arranged for assessing, whether the circuit breaker has failed, and sending, if the circuit breaker has failed, a trip signal to an adjacent circuit breaker. The assessment is based on the measured current. The stability of HVDC grids may be improved by sending, in case of a breaker failure, a trip signal to adjacent circuit breakers. Further, a method of breaker failure protection for an HVDC circuit breaker is provided. | 03-28-2013 |
20130088802 | FAULT PROTECTION OF HVDC TRANSMISSION LINES - A protection system for high voltage direct current, HVDC, transmission lines is provided. The protection system includes a direct current, DC, bus, a device configured to connect an HVDC transmission line to the bus, at least one DC circuit breaker arranged for disconnecting the transmission line from the bus upon reception of a trip signal, current and voltage sensors, an inductor arranged such that the current through the transmission line passes the inductor, and a fault detection unit. The fault detection unit is arranged for assessing, on the basis of current and/or voltage measurements, whether a fault exists on the transmission line, and sending, if a fault is detected on the transmission line, a trip signal to the circuit breaker. The additional inductance limits the rise in fault current and facilitates a selective fault detection. Further, a method of fault protection for an HVDC transmission line is provided. | 04-11-2013 |
20130328569 | Method And Arrangement For An Internal Failure Detection In A Y-Y Connected Capacitor Bank - A method for detecting an internal failure in a capacitor bank connected to a power system, wherein the capacitor bank includes a plurality of capacitor units that are divided into two Y sections. Each phase in each of the Y sections define a leg and each leg includes series and/or parallel-connected capacitor units. The internal failure may occur in one or more capacitor elements or units or involve one or more legs. The method includes measuring the phase current in one of the phases, calculating the root mean square value, denoted by RMS, of the measured phase currents, measuring the unbalance current between the two sections, calculating the RMS value of the measured unbalance currents, and detecting the phase angle between the measured phase current and the measured unbalance current. | 12-12-2013 |
20130338946 | Method And Arrangement For Detecting An Internal Failure In H-Bridge Connected Capacitor Bank - A method for detecting an internal failure in a capacitor bank connected in one phase or more phases respectively to a power system. The capacitor bank includes a plurality of capacitor units. Each of the capacitor units includes a plurality of capacitor elements connected in parallel and/or series. The capacitor units are further divided into two strings and a current transformer is arranged in the midpoints of the two strings so that the capacitor units are further divided into four quadrants and the internal failure(s) may occur in one or more capacitor elements or units and involves one or more capacitor quadrants. The method includes initiating an alarm and/or a trip signal when the determined total number of internal elements failures exceeds a first or a second threshold value. | 12-19-2013 |
20140117912 | System For Detecting Internal Winding Faults Of A Synchronous Generator, Computer Program Product And Method - A system, method and computer program product for monitoring including detecting internal faults especially inter-turn faults of a synchronous generator and thus protecting the synchronous generator. The synchronous generator includes a winding for each phase of a power network, a terminal for each phase arranged on a terminal side of the synchronous generator, and connected to the respective winding, the terminals on the terminal side are connected to an electrical power network, and the synchronous generator is arranged to input power to the electrical power network by means of the terminals. | 05-01-2014 |
20140254053 | TRAVELLING-WAVE BASED FAULT PROTECTION OF HIGH-VOLTAGE TRANSMISSION LINES - An improved method of fault detection in a high-voltage direct current (HVDC) power transmission line is provided. The fault detection is based on fault-induced travelling waves. The method comprises estimating an amplitude of fault-induced travelling waves at the fault location, and calculating a fault resistance (R | 09-11-2014 |