Hitachi Energy Switzerland Ag

Abb Technology Ag

Hitachi Energy Ltd

Abb Schweiz Ag

Abb Power Grids Switzerland Ag

Michael Stanek

Anil Talluri

Urmil Parikh

Soumya Kanta

Lorenz Müller

Mehulbhai Ghanshyambhai Sonagra

A method to detect an electrical making instant for a coupled load is provided. A measured terminal voltage is obtained for each phase of one or more phases of an electrical equipment from a voltage measuring device, during an energization operation of the electrical equipment through a switching device. Further, circuit configuration parameters associated with the electrical equipment is obtained. A processed voltage is determined, for the one or more phases of the electrical equipment based on one or more of the measured terminal voltages of the electrical equipment and a mapping table, which comprises a mapping between the circuit configuration parameters and a computation to be performed on the measured terminal voltage(s). An electrical making instant of a pole of the switching device associated with a phase of the one or more phases is determined based on the processed voltage for monitoring the energization operation of the electrical equipment.

Determination of electrical making instants using load voltage for coupled loads

A power system comprises a power source, a transmission line coupled to the power source through a circuit breaker, a shunt reactor coupled to the transmission line, and a current transformer connected in series with the shunt reactor. A method for controlling the circuit breaker of the power system comprises processing an output signal of the current transformer to obtain the voltage on the transmission line by determining a time derivative of a current sensed by the current transformer. The method further comprises performing, by at least one control or protection device, a control or protection operation (e.g., auto-reclosing) based on the determined time derivative of the current sensed by the current transformer.

Method and device for controlling at least one circuit breaker of a power system

A method for controlled switching of a circuit breaker is described. The method includes initiating operation of the circuit breaker at an initiation time derivable from an initiation time function by calculating a value of the initiation time function with respect to a command instant. The initiation time function is a sum of the command instant and a command delay time. The initiation time function depends on a first parameter and a second parameter. At least one of: the partial derivative of the initiation time function with respect to the first parameter is dependent on the second parameter or the partial derivative of the initiation time function with respect to the second parameter is dependent on the first parameter. Further, a system for controlled switching according to the method and a circuit breaker including the system are described.

Controlled switching of a circuit breaker

The invention relates to monitoring operation of a switching device in a power system, where a load is connected to a power source through the switching device. The load has windings, with coupling between at least one of two or more phases of a winding, and two or more windings of the load. The method includes obtaining measurements of at least one of voltages and currents, at one or more of a source and load side. Further, the method determines an electrical parameter associated with electrical switching of one or more poles. The parameter for each pole is determined based on at least one of voltage measurements at the source and load side, and line measurements associated with at least one winding. The values of the electrical parameter are monitored to determine the switching instant of the pole, for determining mechanical operating time deviation for estimating future switching instants.

Method and device for monitoring operation of a switching device for controlled switching applications

A method for phase controlled energizing of a power transformer includes acquiring electrical voltage signal from a voltage sensing device connected to the power transformer. Determining a first characterizing data in the voltage signal within a pre-determined set of cycles at about an opening operation of a circuit breaker and determining a second characterizing data within the pre-determined set of cycles in the voltage signal subsequent to the opening operation of the circuit breaker. Estimating a level of magnetization of the core of the power transformer based on at least one of second characterizing data, and the first characterizing data and the second characterizing data. Operating the circuit breaker at a determined instant of switching based on the estimated level of magnetization for a phase controlled energizing of the power transformer by the circuit breaker.

Method for phase controlled energizing of power transformer

The method for mains-synchronous switching of circuit breakers comprises the following method steps: measurement of the current flowing through a circuit breaker () and measurement of a mains voltage on a first side of the circuit breaker (), additional voltage measurement on a second side of the circuit breaker (), feeding of all the measurement signals to a control device (), deciding in the control device (), on the basis of the characteristic data stored there, which measurement signal will be used as the reference value for the mains-synchronous tripping of the circuit breaker (), generating a switching command, which initiates the mains-synchronous switching of the circuit breaker () on the basis of this decision, and carrying out the switching command by the circuit breaker ().

Method for mains-synchronous switching of circuit breakers, and an apparatus for carrying out this method

A method and an apparatus are disclosed for disconnection of a fault current which has occurred in an AC power supply system. A disconnection command which is produced in a protective device is supplied to a synchronization controller in order to open a circuit breaker, in which synchronization controller a command is delayed until the circuit breaker can be opened in synchronism with the power supply system. The method includes monitoring of the disconnection command emitted from the protective device and monitoring a fault-current signal, or a status signal emitted from the circuit breaker, and formation of an emergency disconnection command if the fault-current signal or the status signal is still present following a delay time after emission of the disconnection command, which delay time is greater than a sum of a natural response time of the circuit breaker and a time for quenching of a switching arc produced on opening of the circuit breaker.

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Gebenstorf, Switzerland

Michael Stanek