Abstract: A high voltage inverter cascades a plurality of multiple voltage level inverter modules each fed by an isolated dc energy unit to reduce the number of stages of the inverter required to generate a desired ac voltage. Thus, where the dc energy unit includes the secondary winding of an ac transformer, the number of each winding needed is reduced. By using active rectifiers operated in a boost mode to convert the transformer secondary voltage to dc for powering the inverter modules, regenerative operation can be achieved.
Type:
Grant
Filed:
October 23, 1998
Date of Patent:
June 6, 2000
Assignee:
Siemens Power Transmission & Distribution, Inc.
Abstract: An electrical utility meter includes measurement error diagnostic capabilities with intelligent communication capabilities. In an exemplary embodiment, the present invention includes an electrical utility meter for measuring energy consumption by a load. The electrical utility meter includes, sensor circuitry, a conversion circuit, a communication circuit, and a controller. The sensor circuitry connects to a meter socket. The meter socket connects to a plurality of power lines that, in turn, connect the load to a source of electrical power. The source of electrical power provides power to the load in a plurality of phases. The sensor circuitry generates voltage and current measurement signals representative of the voltage and current waveforms on the plurality of power lines.
Type:
Grant
Filed:
August 1, 1997
Date of Patent:
March 28, 2000
Assignee:
Siemens Power Transmission & Distribution, Inc.
Inventors:
Warren T. Martin, William James Watson, Gregory A. Grisham, Michael K. Anderson, Randal K. Bond
Abstract: A lockable circuit breaker racking mechanism is provided with a breaker type detection mechanism preventing locking and removal of the key unless the correct breaker type has been installed. The same locking mechanism can also be used to secure the racking mechanism in the trip-free position.
Type:
Grant
Filed:
May 2, 1997
Date of Patent:
February 22, 2000
Assignee:
Siemens Power Transmission & Distribution, Inc.
Abstract: An electrical utility meter includes a controller that determines a list of highest demands using event-triggered windows of time to ensure that only one of the entries on the list corresponds to any one high consumption event. The controller generates a demand value corresponding to the quantity of energy consumed within a demand interval, and then determines whether the demand value for the demand interval is greater than a smallest demand value on a list of highest demands in a memory location. If so, the controller opens a demand window, the demand window having a duration exceeding the demand interval. The controller then obtains a plurality of additional demand values for the duration of the demand window, each of the additional demand values corresponding to one of a plurality of additional demand intervals within the demand window. The controller records in the list of highest demands in the memory location a select one of the demand value and plurality of additional demand values.
Type:
Grant
Filed:
August 1, 1997
Date of Patent:
February 1, 2000
Assignee:
Siemens Power Transmission & Distribution, Inc.