Matches 1 - 43 out of 43
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7622886 Method for determination of the risk to disturbance-free operation of a frequency converter  
The invention relates to a method for determining the chance of a disturbance-free operation of a frequency converter ( 2 ) connected to a feeding network ( 18 ). According to the invention, during...
7603203 Method for voltage instability load shedding using local measurements  
A method of voltage instability load shedding, that includes the steps of measuring current and voltage waveforms of an electrical system at a local bus estimating the Thevenin equivalent...
7532955 Distributed protection system for power distribution systems  
There is disclosed a protection system for a power distribution system having a plurality of breakers arranged in a hierarchy. The protection system has a network and a breaker coupled to the power...
7519454 Location determination of power system disturbances based on frequency responses of the system  
A system for detecting and locating a disturbance event within a power grid includes a series of frequency disturbance recorders (FDRs) taking measurements in the power grid at dispersed points of...
7447567 Electric power system suppressing corona discharge from viewpoint of environment  
The present invention provides an electric power system for stably supplying power while suppressing corona discharge generating ultraviolet radiation which may cause health problems in human...
6985800 Protection of an electric power transmission network  
For the control of an electric power transmission network, where local protection functions are implemented by a plurality of local protection devices ( 3,3 a, 3 b, 3 b′ ,3 c ) located at a...
6871225 Synthetic corn hybrid P67  
A revision to a Power Management Control System includes an improved waveform client/waveform server communication interface based on a first inter-process communication protocol, preferably DCOM....
6718213 Variable base load energy management system and method  
The present invention is a system and method for variable base load demand-side energy management. The system of the present invention includes a power reduction device receiving electrical power...
6675071 Power quality utility metering system having waveform capture  
A method of monitoring variations is carried out within an electrical energy meter containing means therein for metering a quantity of electrical energy generated by a supplier and transferred via...
6473723 Mimic high pass filter in a protective relay  
A mimic filter which can be implemented in analog or digital circuitry, and which removes dc offset or other noise from an input signal using a pseudo-differentiation technique. The input signal is...
6459998 Sensing downed power lines  
In systems embodying the invention, a “downed” power line is detected by sensing whether there is an open circuit along the power line and producing an indication that an open circuit condition...
6459997 Method for event analysis at an intelligent electronic device  
A method of event analysis in an intelligent electronic device is presented. The intelligent electronic device includes a microprocessor and associated memories. An algorithm (program) stored in a...
6459960 Distance relay equipment  
A short-circuit distance relay has a short-circuit distance relay element that calculates a fault impedance from voltage and current which are introduced from a power system and that compares the...
6185482 System and method for rms overcurrent backup function  
A method and apparatus for over current backup protection is provided. The method generates a set of root mean square (rms) values from samples that are taken from the system current. Several rms...
6173216 Protective relay with improved, sub-window cosine filter  
As a variation of the non-orthogonal filter, a phasor estimate is computed by using an N-point window. An aspect of the sub-window cosine filter is to repeat the basic cosine filter for only...
6154687 Modified cosine filters  
A high sample rate cosine filter eliminates DC components by summing them such that they sum to zero. A non-orthogonal cosine filter is also provided. When the cosine filter is applied for N=4...
6141634 AC power line network simulator  
In an illustrative embodiment, the AC power line network simulator includes an enclosure for containing elements of the system. An AC coupling network coupled to the network simulator implements...
6112136 Software management of an intelligent power conditioner with backup system option employing trend analysis for early prediction of ac power line failure  
A software management system of an intelligent power conditioner with backup system option employing trend analysis for early prediction of AC power line failure. An AC line power conditioner...
6104967 Fault-tolerant battery system employing intra-battery network architecture  
A distributed energy storing system employing a communications network is disclosed. A distributed battery system includes a number of energy storing modules, each of which includes a processor and...
6081768 Digital peak detector  
A method and system for detecting the peak of respective half-cycles of a sinusoidal waveform. The sinusoidal waveform is rectified and only sample points above a first threshold are analyzed. The...
5839093 System for locating faults and estimating fault resistance in distribution networks with tapped loads  
Both fault location and fault resistance of a fault are calculated by the present method and system. The method and system takes into account the effects of fault resistance and load flow, thereby...
5768079 Adaptive ground and phase fault detection for a power distribution system  
An adaptive method and apparatus for detecting fault conditions in a power distribution system that services both single phase loads and three phase loads. The present invention accomplishes this...
5724247 Method of generating a signal indicating the direction of a short-circuit  
A process for generating a direction signal indicating the direction of a short-circuit current in a power transmission line to be monitored. To reliably produce a direction signal even in the...
5608327 Methods and apparatus for identifying faulted phases on an electric power transmission line  
The invention provides method and apparatus for identifying the faulted phases on the occurrence of a single phase fault simultaneously on both circuits of a double circuit electric power...
5426590 Device for numerical computation of a symmetrical component of an electtical quantity of a three-phase power system and relay incorporating it  
The computing device comprises non-recursive, digital filters, with finite impulse response, computing, from samples taken over a period of the power system, for at least two distinct phases, two...
5170360 Computer-based metering arrangement including a circuit interrupter  
A circuit breaker system uses a microprocessor for calculating at least one function of a measured current flow. The microprocessor provides other functions such as serial data stream...
5164876 Static trip device comprising an earth protection desensitization system  
The differential tripping threshold of the trip device is a polynomial function of an order greater than or equal to two of the highest phase current flowing in the power system protected by the...
5058031 Multilevel phase unbalance compressor motor protection system  
A method of protecting the compressor motor of a refrigeration system using a multiphase AC power source. The method comprises the steps of monitoring each phase of the power supply to the...
4879624 Power controller  
A system is disclosed for sequentially disconnecting multiple phases of a first power source (12) from an electrical load (14) requiring a minimum of interruption and connecting a second power...
4878142 High resistance ground fault protection  
A protection device for high resistance ground faults in a power network according to the invention has a fault detection principle which is based on an indirect study of non-harmonic frequency...
4864453 Protective relay with selective phase selection for double lines  
The invention comprises a protective relay with selective phase selection in electric power distribution systems when there are double transmission lines (M1-P1,M2-P2) between two stations (TM, TP)...
4855861 Longitudinal differential protection  
The present invention comprises a longitudinal differential protective relay for protection and supervision of power line zones in a distribution system. The protective relays are located at each...
4835706 Centralized control system for controlling loads such as an electric motor  
A centralized control system for controlling loads includes local or slave control stations, the number of which corresponds with the number of electric motors as loads, the local control stations...
4731689 Directional detection in connection with faults in a power supply network  
A method and a device for directional detection of a fault on a power transmission line extending between two stations (P, Q). In one of the stations (P) there is a travelling wave model which, by...
4694373 Circuit breaker with digital solid-state trip unit with optional functions  
Digital solid-state trip unit designed to provide protection against phase faults, notably overloads and short-circuits and optional functions, in this case ground fault protection and load...
4663539 Local power switching control subsystem  
Each digital module in a network is provided with a local power switching control subsystem wherein the local module uses a local power switching control logic card which controls main power and...
4557686 Control of the flow of fuel to multiple burners  
The flow of offgas from a common source as a fuel for multiple boilers is controlled so as to maintain a desired minimum pressure for the offgas supply unless the maintenance of such a desired...
4541058 Protective relay system  
A protective relay system for protecting a power system includes a selection circuit, a comparing circuit, and a data processing unit. The selection circuit time-sequentially switches a plurality...
4455612 Recursive estimation in digital distance relaying system  
Digital distance relaying of a three-phase electric power transmission line depends on accurate estimation of the postfault voltage and current phasors during the first postfault electrical cycle,...
4445183 Electrical switch  
An electrical switch or power controller is provided controlling the application of a source voltage to a load under the control of an electrical command signal, resulting in the development of a...
4443854 Current sensor responsive to symmetrical and asymmetrical currents and current limiting protector utilizing same  
A current limiting protector for use in electric power transmission lines includes a conductive strip of material and a chemical charge for physically interrupting the conductive strip in response...
4398255 Polyphase angle estimator  
A high speed relay for detecting multiphase faults using operating and polarizing signals from static transmission line protective relays provides an instantaneous estimate of the relative phase...
4276605 Method and apparatus for supervising a digital protective relaying system  
In a method and apparatus for supervising a digital protective relaying system, a first type of electrical quantities in an electric power system, each having a certain magnitude, are detected,...
Matches 1 - 43 out of 43