Aclara Technologies, LLC

Distribution Control Systems, Inc.

Aclara Power-line Systems Inc.

John B Hessling, Jr

David W Rieken

Benjamin A Hammond

Quentin H Spencer

Dennis L Kelley

William J Davis

Michael R Walker, Ii

Krister Lagerstrom

An improvement in a Two Way Automated Communications System (TWACS) requires only three of six previously required vectors to communicate with remote communication equipment (RCE) devices installed in the three phases of a utility's low voltage distribution network for concurrent outbound signal communications over the TWACS. The reduction in vectors allows an outbound injection silicon-controlled rectifier (SCR) array used for such purposes to be greatly simplified and further allows the SCRs in the array to be operated independently, and therefore concurrently.

Concurrent outbound communications in a TWACS

As disclosed, a two-way automatic communications system (TWACS) and method are used by an electrical utility in which outbound messages are sent from the utility to a consumer and inbound messages are sent from the consumer to the utility. The respective outbound and inbound messages are sent and received over the utility's power distribution system. A receiver including an analog filter component, an A/D converter and a digital processor detects the outbound messages. A substation transceiver is configured for sending analog outbound messages from the utility to a consumer. A transponder is configured for sending inbound messages to the transceiver from the consumer to the utility, the respective outbound and inbound messages being modulated on a mains signal of the utility's power distribution system. The receiver in another form includes an analog filter component, a detecting circuit and a demodulator.

TWACS transmitter and receiver

Improvements in the detection of TWACS outbound message signals. A first improvement involves matching some (or all) of the intermediate points in an outbound preamble occurring between bits of the preamble currently being detected. This reduces the possibility of a false synchronization and therefore decreases the probability of missing outbound message signals. A second improvement is to require some or all of the known preamble bits to exceed a predetermined threshold where both the thresh-old and which bits are adjustable. An additional approach is using 4-8 additional buffers in a transponder to detect preamble patterns in the outbound message. Each half cycle of the outbound message waveform requires entering a bit only into the buffers active for the particular frame of reference in which the message is being transmitted, since only buffers for that frame of reference are employed. The process continues until all bits specified to be sent, based on the length of the outbound message, are extracted. A CRC is then performed for the message. Using this method eliminates the problem of inbound messages being detected as outbound messages, and the resulting 'blindness' of the transponder. It further makes the transponders less sensitive to noise which currently causes the transponder to detect a preamble when there is none, resulting in a valid outbound message being missed.

Detection of outbound message signals in a power line two-way communications system

A method for concurrently communicating over each phase of an electrical power distribution network (N). A first outbound signal (SO) is transmitted over one phase (AN-A) of a bus (S) by an outbound modulation unit. The unit is released as soon as the first outbound signal (SO) is transmitted so the unit can transmit a second outbound signal (SO) over a second phase (BN-B or CN-C) of the bus. The second outbound signal is transmitted concurrently with an inbound signal (IB) sent in response to the first outbound signal (SO). The unit is again released, as soon as the second outbound signal (SO) is transmitted, so the unit can transmit a third outbound signal (SO) over the third phase (BN-B or CN-C) of the bus. This third outbound signal is transmitted concurrently with a second inbound signal (IB) sent in response to the second outbound signal (SO). The method allows concurrent communications over all three phases of the network (N).

Concurrent phase communication in TWACS

In a communication system in which outbound information in the form of multi-bit messages is carried by cyclic waveforms over an electric power distribution network, the signal is detected independently at any of a plurality of locations remote from the source by obtaining signal data by sampling the cyclic waveform over a predetermined portion of successive cycles. The predetermined portion is divided into a plurality of predetermined ranges. From a predetermined number of bits at the start of each message, the particular predetermined range which contains the greatest signal strength is selected. For the remaining bits of the message, only those samples in the selected range are analyzed to detect the outbound message. To reject cross-talk, preselected ranges in which cross-talk signals are likely to appear are monitored, and the in-phase messages are rejected when theh signal strength in the in-phase range is less than the signal strength in at least one of the cross-talk ranges.

Growing community of inventors

Maryland Heights, MO, United States of America

John B Hessling, Jr