Patent application number | Description | Published |
20080239602 | FAST IMPEDANCE PROTECTION TECHNIQUE IMMUNE TO DYNAMIC ERRORS OF CAPACITIVE VOLTAGE TRANSFORMERS - The present invention relates to methods for providing impedance protection differentiating between in-zone and out-of-zone faults based on instantaneous, digitally derived operating and polarizing, distance comparator signals. The method uses a pair of fast orthogonal filters to derive D and Q components of the input voltages and currents. Two sets of operating and polarizing signals are derived for better speed of response under varying fault moment with respect to the peaks and zero crossings of power signals. Three stages of comparison between the operating and polarizing impedance terms are used. These comparator stages use half a cycle averaging windows, and three-quarters-of-a-cycle windows. The first stage of comparison is based on energy comparator responding to both magnitude and phase information in the signals. Stages 2 and 3 are of phase comparison type, responding mostly at the phase information and neglecting the magnitude information for better immunity to noise and signal distortions. | 10-02-2008 |
20080243413 | SELF-ADJUSTING VOLTAGE FILTERING TECHNIQUE COMPENSATING FOR DYNAMIC ERRORS OF CAPACITIVE VOLTAGE TRANSFORMERS - A method of digitally correcting the raw output voltage from a Capacitive Voltage Transformer (CVT) with the intent to remove transient components impacting on transient accuracy of protection function. A typical CVT is represented using three parameters in the linear CVT model. A digital filter designed based on the three parameters and incorporating a dedicated mechanism to ensure numerical stability of the former. A method of self-adjusting the said filter based on system events and performed after the method has been deployed in the field and supplied from a specific CVT. | 10-02-2008 |
20090312999 | SYSTEMS AND METHODS FOR PREDICTING MAINTENANCE OF INTELLIGENT ELECTRONIC DEVICES - Predictive maintenance systems and methods are described. A method includes measuring environmental conditions using a plurality of sensors within the IED, processing the environmental measurements to determine long-term exposure factors representing historical operating conditions of the IED, applying a reliability model to the long-term exposure factors, determining a numerical measure of IED life based on the long-term exposure factors and the reliability model, comparing the numerical measure of IED life to preselected boundary values, and signaling if the numerical measure of IED life is outside of the preselected boundary values. | 12-17-2009 |
20100194323 | ROBUST ON LINE STATOR TURN FAULT IDENTIFICATION SYSTEM - A system and method for identifying turn faults in a stator of a motor are provided. The method includes determining a normalized cross-coupled impedance from the symmetrical components of measured voltages and currents of the motor. Additionally, the normalized cross-coupled impedance may be normalized to a negative sequence impedance. The negative sequence impedance may be determined through a regression analysis using parameters of the motor, such as line-to-line voltage, horsepower, and number of poles. A system is provided that includes a device having a memory and processor configured to determine a normalized cross-coupled impedance, compare the normalized cross-coupled impedance to one or more thresholds, and trigger and alarm and/or trip the motor. | 08-05-2010 |
20100194324 | STATOR TURN FAULT DETECTION APPARATUS AND METHOD FOR INDUCTION MACHINE - A system and method are provided for correction of parameters used in determination of stator turn faults of an induction motor. An embodiment may include determining a residual impedance and/or a residual voltage of the motor, and correcting a normalized cross-coupled impedance based on the residual impedance and residual voltage. Additional embodiments may include measuring an operating temperature of the motor and determining a negative sequence impedance of the motor based on the temperature. Another embodiment may include measuring voltages and currents of the motor and determining phasors for the voltages and currents using compensation for variations from a nominal frequency of the motor. | 08-05-2010 |
20100195763 | APPARATUS, SYSTEM, AND METHOD FOR CREATING ONE OR MORE SLOW-SPEED COMMUNICATIONS CHANNELS UTILIZING A REAL-TIME COMMUNICATION CHANNEL - An intelligent electronic device creates one or more virtual communications channels using unused or dedicated bits from a primary real-time communications channel. The virtual communications channels are used to transport low-speed information, such as executable commands, or automatic functions not requiring high bandwidth. | 08-05-2010 |
20110063761 | Transformer Differential Protection - Transformer differential protection is provided by measuring a plurality of currents corresponding to a first set of windings and a second set of windings of a transformer, and compensating the currents based on their respective flows through either the first set of windings or the second set of windings. The compensated currents may be intentionally augmented to compensate for magnetizing inrush and/or stationary overexcitation conditions associated with the transformer. Augmentation based on stationary overexcitation, for example, may be based on either harmonic restraint or an addition of a V/Hz ratio to a restraining signal. A complex current ratio is calculated corresponding to the plurality of compensated currents. The complex current ratio may be based on a two-terminal equivalent power apparatus. Then, an alpha plane analysis is applied to the complex current ratio. Based on the alpha plane analysis, a power apparatus that includes the transformer is selectively tripped. | 03-17-2011 |
20110063766 | LINE CURRENT DIFFERENTIAL PROTECTION UPON LOSS OF AN EXTERNAL TIME REFERENCE - A line current differential protection system that uses an external time reference continues providing protection to a power apparatus upon the loss of the external time reference. An external time reference synchronization mode and a channel based synchronization mode may be selectively applied on a per channel basis such that only those channels in the system that are not guaranteed to stay symmetrical use external time reference synchronization. When the external time reference is lost, fallback strategies may be used such as disabling or de-sensitizing the line current differential protection function, switching from the external time reference synchronization mode to a channel based synchronization mode with appropriately selected protection settings, and/or marking the channel as unavailable to isolate the system from the consequences of synchronization errors over this channel and instead using a master-slave mode with other available channels to continue providing line protection with the current differential system. | 03-17-2011 |
20110063767 | CHARGING CURRENT COMPENSATION FOR LINE CURRENT DIFFERENTIAL PROTECTION - Current differential protection with charging current compensation is provided for a power apparatus, such as a power transmission line. Individual terminals dynamically determine their respective contributions, if any, to the charging current compensation value as availability of one or more voltage sources dynamically changes within the power apparatus. Respective terminals calculate local contributions to a charging current compensation value based on local voltage measurements. A loss of a voltage source is handled by adjusting multipliers for the remaining compensation points to reflect the total charging current. A local contribution is suppressed when the local voltage source is no longer available. After applying the local contributions, an alpha plane analysis may be used to determine when to trip the power apparatus. | 03-17-2011 |
20110063769 | EQUIVALENT ALPHA PLANE FAULT DETERMINATION FOR A MULTI-TERMINAL POWER APPARATUS - Current differential protection is provided for a multi-terminal power apparatus, such as a power transmission line. Currents measured at each of the multiple terminals are used to calculate a differential current and a restraining current, which are then converted into a first equivalent current and a second equivalent current of an equivalent two-terminal power apparatus. In the equivalent two-terminal power apparatus, a differential current derived from the first and second equivalent currents is substantially equal to the differential current of the original multi-terminal power apparatus. Similarly, a restraining current derived from the first and second equivalent currents is substantially equal to the restraining current of the original multi-terminal power apparatus. The first and second equivalent currents may be used in an alpha plane analysis to determine whether or not to trip the multi-terminal power apparatus. | 03-17-2011 |
20110310893 | SYSTEMS AND METHODS FOR DATA PACKET TRANSMISSION - The present disclosure relates to the transmission of data packets, and to systems and methods for improving the utilization of available bandwidth. In various embodiments, a transmitting device may calculate a first data integrity value based on the payload of a network packet and a static datum (e.g., sender identification information). The first data integrity value is transmitted with the network packet while the static datum is omitted. A receiving device may be configured to replace the omitted static datum upon receipt of the network packet. This static data is pre-configured in the receiving device or communicated using an alternative method. The receiving device may then calculate a second data integrity value based on the received network packet payload and the static datum. The second data integrity value may only match the first data integrity value if the transmitting device and receiving device use the same static datum. | 12-22-2011 |
20120057266 | SYSTEMS AND METHODS FOR INDEPENDENT SELF-MONITORING - An Intelligent Electronic Device (IED), such as a protective relay, may monitor and/or protect an electrical power system by detecting fault conditions using stimulus inputs from the electrical power system. The IED may operate (take protective actions) when fault conditions are detected. A monitoring device may supervise the IED. The monitoring device may detect power system disturbances independently of the IED, using the same stimulus inputs (or a subset thereof) used by the IED to implement its protection function(s). The monitoring device may supervise the IED using hard-coded supervision, soft-coded supervision, and/or user-configurable supervision. The IED may be prevented from operating outside of an operating window defined by the monitoring device. Components of the monitoring device may be separated and/or isolated from the IED, such that a failure in certain IED components may not cause a simultaneous failure or malfunction of the monitoring device. | 03-08-2012 |
20120134061 | APPARATUS, SYSTEM, AND METHOD FOR CREATING ONE OR MORE SLOW-SPEED COMMUNICATIONS CHANNELS UTILIZING A REAL-TIME COMMUNICATION CHANNEL - An intelligent electronic device having a slow speed communications link creates one or more virtual communications channels using unused or dedicated bits from a primary real-time communications channel. The virtual communications channels are used to transport low-speed information, such as fault location information, device configuration information, device revision information, and date/time information. | 05-31-2012 |
20120162843 | LINE CURRENT DIFFERENTIAL PROTECTION UPON LOSS OF AN EXTERNAL TIME REFERENCE - A line current differential protection system that uses an external time reference continues providing protection to a power apparatus upon the loss of the external time reference. An external time reference synchronization mode and a channel based synchronization mode may be selectively applied on a per channel basis such that only those channels in the system that are not guaranteed to stay symmetrical use external time reference synchronization. When the external time reference is lost, fallback strategies may be used such as disabling or de-sensitizing the line current differential protection function, switching from the external time reference synchronization mode to a channel based synchronization mode with appropriately selected protection settings, and/or marking the channel as unavailable to isolate the system from the consequences of synchronization errors over this channel and instead using a master-slave mode with other available channels to continue providing line protection with the current differential system. | 06-28-2012 |
20130250458 | LEVERAGING INHERENT REDUNDANCY IN A MULTIFUNCTION IED - Disclosed herein are systems and methods for leveraging the inherent redundancy of electrical measurement inputs available to microprocessor-based intelligent electronic devices (IEDs). Specifically, an IED may receive a plurality of electrical measurements associated with an electric power delivery system, such as measurements associated with a generator. A first protection module may be configured to detect a first type of electrical disturbance using a first subset of the plurality of electrical measurements. A second protection module may be configured to detect a second type of electrical disturbance using a second subset of the plurality of electrical measurements. A first redundant protection module may be configured to verify the detection of the first type of electrical disturbance using at least a portion of the second subset of the plurality of electrical measurements. | 09-26-2013 |
20140191591 | Preventing Out-of-Synchronism Reclosing Between Power Systems - The present disclosure provides apparatus, systems, and methods for preventing out-of-synchronism closing between power systems. An intelligent electronic device (IED) apparatus may include a control component and a delay component. The control component is configured to selectively control opening and closing of a breaker. The control component selectively outputs a close signal to cause the breaker to connect a first portion of a power delivery system to another portion of the power delivery system. The delay component is configured to delay output of the close signal to the breaker. The delay component includes circuitry independent from control by the control component and the delay component is inconfigurable from a remote location. | 07-10-2014 |
20140269736 | Transmission of Data Over a Low-Bandwidth Communication Channel - Disclosed herein are various systems and methods that may improve the transmission of data over low-bandwidth communication channels in an electric power delivery system. Devices communicating across a low-bandwidth communication channel may implement several approaches, according to various embodiments disclosed herein, to reduce the data transmitted across the low-bandwidth communication channel and to prioritize the transmission of time-sensitive and/or more important information with respect to other data. Various embodiments disclosed herein may inspect packets to be transmitted across a low-bandwidth communication channel in order to identify high priority data. High priority data may be time-sensitive information, and accordingly, transmission of such data may be prioritized over other data in order to reduce transmission latency of the higher priority data. | 09-18-2014 |
20150081234 | POWER LINE PARAMETER ADJUSTMENT AND FAULT LOCATION USING TRAVELING WAVES - Fault location using traveling waves in an electric power delivery system according to the embodiments herein uses line parameters that are adjusted using traveling wave reflections from known discontinuities in the electric power delivery system. The arrival times of a traveling wave and a reflection of the traveling wave from a known discontinuity may be used to adjust parameters of the electric power delivery system such as, for example, line length. The adjusted parameter can then be used to more accurately calculate the location of the fault using the traveling waves. | 03-19-2015 |
20150081235 | FAULT LOCATION USING TRAVELING WAVES BY CALCULATING TRAVELING WAVE ARRIVAL TIME - A location of a fault in an electric power delivery system may be detected using traveling waves instigated by the fault. The time of arrival of the traveling wave may be calculated using the peak of the traveling wave. To determine the time of arrival of the peak of the traveling wave, estimates may be made of the time of arrival, and a parabola may be fit to filtered measurements before and after the estimated peak. The maximum of the parabola may be the time of arrival of the traveling wave. Dispersion of the traveling wave may also be corrected using an initial location of the fault and a known rate of dispersion of the electric power delivery system. Time stamps may be corrected using the calculated dispersion of the traveling wave. | 03-19-2015 |
20150081236 | TRAVELING WAVE VALIDATION USING ESTIMATED FAULT LOCATION - Electric power delivery system fault location systems and methods as disclosed herein include validation of the received traveling wave fault measurements. Validation may include estimating a location of the fault using an impedance-based fault location calculation. Time windows of expected arrival times of traveling waves based on the estimated fault location and known parameters of the line may then be established. Arrival times of traveling waves may then be compared against the time windows. If the traveling waves arrive within a time window, then the traveling waves may be used to calculate the location of the fault. | 03-19-2015 |