Abstract: A set of irregular LDPC (Low Density Parity Check) codes having a pseudo-random structure and low encoding complexity. A block-cyclic LDPC code has an irregular row or an irregular column weight and includes a parity check matrix and an encoding matrix each of which has a pseudo-random structure. This allows the code to have the irregular row weight or irregular column weight together with an overall randomness to the code structure. Blocks within the code can be shortened, adjacent blocks of code can be overlapped, and adjacent columns within a block can be arbitrarily permuted so to change the weighting of rows and columns. The LDPC codes are particularly useful in two-way communications system for an electrical distribution system (1) to restore data lost or corrupted during its transmission.

Abstract: A quick response system incorporated in a TWACS for mapping an outage in an electrical distribution system without having to continuously poll the electrical meters connected to the system. In a primary embodiment of the invention when a fault is sensed to have occurred, the amplitude of the fault is measured to determine if the fault is a medium voltage fault, or a low voltage fault. The pattern of the fault signature and change in load, both before and after the fault, are examined to determine what protective device was triggered by the fault. Using this information, and knowledge of the number and location of electrical meters connected in the distribution system, a population of meters to be polled is determined. By polling the identified population, a map of the extent of the outage is readily determined, and the time to respond to the fault and restore service is reduced.

Abstract: Tamper detection apparatus for an electric meter (M) installed at a facility supplied power through an electrical distribution system, the meter being connected to the facility using a receptacle (K) and monitoring electricity usage at the facility for electricity delivered to the facility flowing through the meter. A sensor (RR) senses movement of the meter more than a predetermined amount with respect to the receptacle, whether or not electricity is flowing through the meter, and produces a tampering signal when this occurs. A second and optional sensor (Z) senses the proximity of the meter to its receptacle with removal of meter from its receptacle producing a tampering signal representative thereof. Generation of a tampering signal results in a tamper alert signal being transmitted to the system through a two-way communications path established between the facility and the system.

Abstract: An automatic meter reader (AMR) used in an electrical distribution system has a communications module (26, 28) housed within an enclosure (12) for two-way message communications with a utility (U) to report information to the utility concerning electricity usage at the AMR site. The communications module includes at least one resistive element (RR) which may have an associated heat sink (H) and to which current is supplied during communications. A heat flow control (30) used with the resistive element controls the release of heat generated thereby during a message. This includes applying at least one layer (L) of a phase change material (PCM) to the resistive element, or its heat sink, to control the increase in temperature of ambient air inside the AMR enclosure during two-way communications to a temperature below a critical temperature (Tmax). This allows a message of greater length to be used for communications between the utility and AMR than was previously possible.

Abstract: A quick response system incorporated in a TWACS for mapping an outage in an electrical distribution system without having to continuously poll the electrical meters connected to the system. In a primary embodiment of the invention when a fault is sensed to have occurred, the amplitude of the fault is measured to determine if the fault is a medium voltage fault, or a low voltage fault. The pattern of the fault signature and change in load, both before and after the fault, are examined to determine what protective device was triggered by the fault. Using this information, and knowledge of the number and location of electrical meters connected in the distribution system, a population of meters to be polled is determined. By polling the identified population, a map of the extent of the outage is readily determined, and the time to respond to the fault and restore service is reduced.

Abstract: A method of providing a graphic display (SD) of an electrical distribution network (N) to provide network personnel insight as to network operation comprising. A segment of the network is monitored to obtain information about predetermined types of incidents which occur. The information is then processed to ascertain where the incidents occurred and the number of incidents which occur over a predetermined period of time. The results are presented in a graphical display which includes the number of incidents occurring at each location within the network segment, and the number of incidents which occurred at each location during previous period of time at the respective locations.

Abstract: Apparatus (10) for controlling supply of electricity through an electrical distribution network to a customer. An electrical meter (12) is plugged into an electrical socket (14) at a customer's premises. Electricity flows from a power line through the socket into the premises, the amount of electricity used being measured by the meter. The apparatus is interposed between the meter and the socket and includes a switch (18) to interrupt flow of electricity into the premises. The switch is controlled by the utility, preferably through programming of the apparatus or through a TWACS® communication system. This enables the utility to selectively control supply of electricity to the premises apart from the flow of electricity to any other premises connected to the same power line (L).

Abstract: A method for concurrently communicating over each phase of an electrical power distribution network (N). A first outbound signal (SO1) 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 (SO1) is transmitted so the unit can transmit a second outbound signal (SO2) over a second phase (BN-B or CN-C) of the bus. The second outbound signal is transmitted concurrently with an inbound signal (IB1) sent in response to the first outbound signal (SO1). The unit is again released, as soon as the second outbound signal (SO2) is transmitted, so the unit can transmit a third outbound signal (SO3) over the third phase (BN-B or CN-C) of the bus. This third outbound signal is transmitted concurrently with a second inbound signal (IB2) sent in response to the second outbound signal (SO2). The method allows concurrent communications over all three phases of the network (N).

Abstract: A method of controlling the current level of an inbound signal (Si) used in a TWACS (two-way communication system) for an electrical distribution system. The inbound signal conveys operational information and data on the performance of the system. The method includes first measuring the current (I) of the inbound signal. This current measurement is performed for each of a predetermined number of successive inbound signals. The root mean square (RMS) value of the measured currents is then determined. Operation of a solid state device (SCR) used to generate the inbound signal is now controlled as a function of the root mean square value. A line current propagating through the electrical distribution system is now modulated with the inbound signal. The inbound signal occurs at a predetermined range of angles (X) within a line voltage cycle regardless of variations in the line voltage characteristics. This enables the inbound signal to be readily detected.

Abstract: An interface circuit (10) for use with electronic metering equipment (E) to provide a linear output response to an AC or analog input. An air core transformer (12) has a first coil or winding (12a) connected to a load (L). An AC current I.sub.LOAD is produced by the load and is coupled to a secondary coil or winding (12b) of the transformer. The transformer has an air core rather than a ferromagnetic core so to have no saturable core. Because no load is drawn by transformer coil, the voltage across a terminal of the coil equals the EMF induced in the coil. The EMF, in turn, equals the mutual inductance of the coils multiplied by the rate of change of magnetic flux linkages over time. The output from the transformer is applied as an input to an operational-amplifier (16) which has a high input impedance. Further, the amplifier is a low drift amplifier which performs a linear amplification of the input signal provided thereto.

Abstract: A two-way communication system (TWACS) used with an electrical power distribution network N. The TWACS provides both outbound and inbound messages to and from remote network locations. A method of detecting and decoding unsolicited inbound messages from remote locations first involves generating the message in response to a time independent event occurring at the remote location. Formation of the message includes both generating a series of message bits, each of which has a prescribed format, and affixing a preamble to the front end of the message which comprises a plurality of bits arranged in a predetermined pattern. The message is then transmitted over any one of a plurality of communication channels n normal used for two-way communications. Since the event triggering the unsolicited inbound message is independent of time, the time of transmission is random.

Abstract: A gasketless enclosure (10) for housing outdoor electrical equipment. The enclosure includes a box (12) having a base (14) and upwardly extending, sidewalls (16A-16D). The walls define an open, upper face, over which fits a cover (18). A closure mechanism (28) includes an upwardly projecting lip (30) formed at the upper end of the sidewalls and extending around the circumference of the box, and a channel (32) formed in the abutting face (34) of the cover and sized to receive the lip. To help prevent moisture from seeping into the interior of the box and harming the equipment housed therein, gutters (42, 44) are formed in the abutting surfaces of the box and the cover. The gutter (44) formed in the box is formed outwardly of the lip, and the gutter (46) formed in the cover is formed outwardly of the channel. The gutter in the cover sits over the gutter in the box when the cover is in place.

Abstract: Signals carried inbound on an electricity distribution network are detected by extracting electrical current information from a waveform of the electricity distribution network, and digitally filtering the electrical current information, thereby forming a digital waveform, to extract signal information contained in the electrical current information. A reference waveform is constructed from a portion of the digital waveform, and the signal information is detected by comparing portions of the digital waveform with corresponding portions of the reference waveform.

Abstract: 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.

Abstract: An electricity meter transponder package includes an electricity meter and a cover for containing the meter. The cover is secured to the meter by a predetermined rotation of the cover with respect to the meter. A first electrical connector-half is fixedly mounted with respect to the meter, that connector-half having terminals electrically connected to the meter. A second electrical connector-half having terminals mateable with the terminals of the first connector-half is fixedly mounted with respect to the cover in a position such that the predetermined rotation of the cover with respect to the meter causes the terminals of the first and second connector-halves to mate to complete electrical connection between their respective terminals. At least one electrical circuit is carried by the cover, which circuit is electrically connected to at least some terminals of the second connector-half.