Patent Description:
If gas pressure within a portion of a gas distribution system gets too high, it can cause pipes to burst, the venting of gas, dangerous pilot lights, damage to appliances and/or buildings, and even fires and explosions. Monitoring gas pressure is a complex matter, in part because pressure can vary due to many factors, including gas supply, user gas demand, pipe lengths, bends, joints, and gas friction with pipe interiors and other gas. Moreover, known systems tend to respond slowly to over-pressure events, in part because of latencies within communication networks, headend application latencies, and human delays. Accordingly, substantial gas pressure increases can result in damage before the increases are detected, reversed and/or mitigated.

<CIT> describes a system for optimally controlling gas flows in a pipeline network having gas import points, gas export points, and pipelines connected therebetween. The pipelines are interconnected by at least one junction. Each gas import point, gas export point and junction has a sensor and a flow control device, both of which correspond to a unique smart meter. Each smart meter includes a communication network interface and a flow control device controller. Each smart meter is capable of repeatedly: (<NUM>) receiving system gas data and first local gas request parameters from at least one other smart meter; (<NUM>) controlling the flow control device via the flow control device controller; (<NUM>) generating local gas values based on an output from the corresponding sensor; (<NUM>) calculating second local gas request parameters based on the local gas values and the system gas data; and (<NUM>) transmitting the system gas data.

<CIT> describes a gas meter system which is capable of accurately deriving the heating value of gas, and a heating-value estimation method. This gas meter system derives the unit heating value of gas passing through first gas meters, and, on the basis of the heating value of the gas passing through the first gas meters disposed on a gas supply pipe for supplying the gas, and within a prescribed range of second gas meters provided separately from the first gas meters, estimates the heating value of gas passing through the second gas meters.

<CIT> describes the present invention includes a valve for connecting to a valve network comprising: at least one valve assemble, having at least one valve to control a fluid or gas flow through an opening in the valve assembly; at least one pressure sensor; viscosity sensor; flow rate detector; and temperature sensor; at least one processor connected to each of the valve and sensors, wherein the processor is capable of controlling the position of the valve based on the information obtained from the sensors; at least one communications module connected to the processor capable of transmitting to and receiving information from the valve network and capable of sending information obtained from the valve assembly to the valve network of the status of the fluid or gas flowing through the valve assembly; and at least one power source that provides power to the valve assembly.

<CIT> describes a device for reading and controlling the gas supply, in which there is an input connector and an output connector of a pipe in which gas flows from a distribution network towards at least a residential user, comprising a logical control unit for the operation of said device and for the storage of predetermined threshold values, characterized by the fact of comprising: a plurality of sensors, operationally connected to said logical control unit, for measuring values of physical quantities and sending these to said logical control unit; a gas supply blocking device, operationally connected to said control logic unit; said control logic unit being configured to compare said values measured and received by said plurality of sensors with said predetermined threshold values, to send alarm signals and to activate said blocking member for blocking of the gas supply, if said measured values are higher than said predetermined threshold values.

The same numbers are used throughout the drawings to reference like features and components. Moreover, the figures are intended to illustrate general concepts, and not to indicate required and/or necessary elements.

Techniques for detecting a high gas pressure situation within a gas delivery system (e.g., for delivery of natural gas to homes and businesses) are described. In one example, a first device measures gas pressure. If a gas pressure that is over a threshold value is detected, the first device sends a message to a second device, which may be near the first device (e.g., both devices may be on a same gas delivery pipeline). The second device may respond by indicating its own gas over-pressure condition, thereby suggesting that the gas over-pressure condition is not localized at the first device (e.g., a first smart gas meter). Alternatively, the second device may not detect and/or report an over-pressure condition, thereby suggesting that the over-pressure condition may be localized to the first device.

In a further example, the first device may share information about its over-pressure condition with devices within a group defined to include the first and the second devices and other devices. Members of the group may share information with devices in any group(s) in which they are members and/or with devices that are within a threshold physical (geographic) distance. An appropriate response may be made within the gas delivery system depending on if the over-pressure condition is localized to the first device, or more widely present within the group of devices. In examples, protective measures may be taken, such as closing valves providing gas to appropriate service sites, and such as sending warning notices to a headend device (e.g., to the utility company), to users' devices including users' cellphones and in-home devices, and to any other device(s) that may assist in mitigating damage and/or injury.

<FIG> shows an example gas delivery system <NUM>. If pressure in an area of the gas distribution system <NUM> is too high, the pressure may cause damage. The gas delivery system <NUM> is configured having devices and techniques of operation that detect, notify and mitigate or resolve overly high gas pressure conditions.

In the example system <NUM>, a major gas main <NUM> supplies gas to several local gas mains <NUM>, <NUM>. In the example, the local gas main <NUM> supplies gas to large gas volume customer(s) <NUM> having associated gas pressure regulators and metering devices <NUM>. The local gas main <NUM> supplies gas to commercial customer(s) <NUM> having associated gas pressure regulators and metering devices <NUM>. The local gas main <NUM> also supplies gas to residential customer(s) <NUM>, <NUM> having associated gas pressure regulators and metering devices <NUM>, <NUM>.

The local gas main <NUM> and the devices attached to it may constitute a group of devices for purposes of an algorithm (discussed at <FIG> and other locations) that detects, notifies and/or mitigates/resolves a situation wherein devices within the logical group detect gas pressure over a threshold value. The group may be based at least in part on knowledge of the topology of the gas delivery system. A topological description of the gas delivery system may be configured within a database or other data structure. In an example, the topological description may include a listing of devices in the system, their characteristics, and how, when, where, and/or to what they are connected. The topology may include "states" of devices, such as a valve being open or closed, or a gas main having a certain pressure, a battery having a certain charge, etc. Similarly, the local gas main <NUM> and devices attached to it may constitute a second group. Each device in the system <NUM> may be considered to be in one or more groups. The groups may be formed in a manner that logically groups devices so that data from one device may be synergistically interpreted using data from other device(s) in the group. For example, if one device recognizes a gas pressure over a threshold pressure value, that event is reported to other devices in a group. A confirmation of high pressure by other devices in the group tends to indicate a region of high gas pressure rather than an area of localized high gas pressure.

A liquid natural gas (LNG) plant <NUM> provides gas to the delivery system <NUM> at local gas main <NUM>. Compressor stations <NUM> create, regulate and/or maintain the gas pressure within gas mains and local delivery pipes within the system <NUM>. An underground gas storage reservoir <NUM> and regulator <NUM> provide additional gas through a gas pipe <NUM> to the system <NUM>.

Within the system <NUM>, gas flows from locations having higher gas pressures upstream (e.g., the LNG plant <NUM>, the compressor stations <NUM>, and the underground storage <NUM>) and to areas having lower pressures downstream (e.g., the customers <NUM>, <NUM>, <NUM> and <NUM>).

Additionally, the gas pressure within the gas delivery system <NUM> can vary from city gate regulators/meters <NUM> in the system to the downstream service point gas pressure regulators and meters. Example factors resulting in pressure drop include pipe length, pipe bends and joints, and internal gas-against-gas and gas-against-pipe friction.

The example system <NUM> is configured to monitor pressure at a plurality of points, thereby providing control systems and techniques of operation that anticipate, detect and/or mitigate unsafe situations, and avoid unsafe situations resulting from network latencies, headend application latencies, and/or human delays. In the example system <NUM>, the gas meter/gas pressure regulator <NUM> is configured to include edge detection and gas pressure notification systems and techniques <NUM>. In an example, the techniques <NUM> are enabled by execution of software, which may be defined in memory and executed by a processor. Other devices shown in the system <NUM> may contain the same or similar edge detection and gas pressure notification systems and techniques <NUM>. The edge detection and gas pressure notification systems and techniques <NUM> are configured and operate according to one or more of the examples shown, discussed and/or suggested by the examples of <FIG>.

<FIG> shows an example gas delivery system <NUM> illustrating example functionality of groups of devices, particularly showing a data-gathering functionality. A first example group <NUM> of devices includes four gas meters <NUM>-<NUM>. The first group <NUM> additionally includes two valves <NUM>, <NUM>. The valves may be associated with segment pipelines or "stub pipelines" off a main gas pipeline (e.g., pipes <NUM>, <NUM> of <FIG>). The valves <NUM>, <NUM> may allow gas to be turned on/off to more than one gas service site (i.e., more than one gas metering device).

The first group <NUM> may also include a group data pool <NUM>, which may be located in any desired location, such as a remote server, one or more of the gas metering devices, or a dedicated device, etc. The data pool <NUM> may include information regarding a topology of some or all of the gas delivery system <NUM>, and time-stamped pressure measurements and/or pressure thresholds of gas pressure measuring devices in one or more groups of devices. The data pool <NUM> may also identify groups of devices according to geography and/or connectivity within the gas delivery system topology. A group may include devices on a segment of gas pipeline serving a related group of gas customers (e.g., related by use of a same gas main and/or related by physical distance between any two devices of less than a threshold value).

The example gas delivery system <NUM> may also include other group(s), represented for drawing simplicity by group <NUM> and gas meter <NUM>. The number of groups and the number of devices in each group may be based on the needs, conditions and design specification of a particular system, and are shown in <FIG> only to illustrate general concepts and not as requirements.

In an example, the gas consumption meters, valves, gas pressure-measuring devices, combined function devices, etc., may be configured in a group based on gas delivery system topology. In the example, some or all of the components (e.g., smart gas metering devices, valves, pipelines, etc.) along a gas pipeline serving a number of customer sites (associated with the smart gas metering devices) may be configured in a logical group. The pipeline may terminate after the last downstream customer's site. In some examples, an over-pressure event (e.g., gas pressure over a threshold) could be resolved by temporarily turning off the gas supply to the pipeline.

In an example of the operation of system <NUM>, devices with pressure sensors (e.g., smart gas metering devices, etc.) can periodically compare their pressure readings to one or more high gas-pressure threshold values. The comparison may be made at prescribed intervals, random times, etc., as indicated by system design requirements, including available battery power, time since detection of an over-pressure event, and/or other considerations. If a device (e.g., a smart gas meter) detects that pressure has passed a relevant threshold value, the device can increase the rate of its gas-pressure sampling. Conversely, if the device detects normal gas pressure values for over a relevant threshold time value, it can decrease the rate of its gas-pressure sampling.

If a threshold gas-pressure value is exceeded, the device can send its latest pressure reading(s)-and in some examples, its relevant threshold values(s)-to its neighboring devices (e.g., devices within the group of devices) that also have gas pressure sensors.

Responsive to a message from a group member (e.g., smart gas metering device <NUM>) sensing a higher than threshold gas pressure, other pressure sensing devices in the group (e.g., smart gas metering devices <NUM>, <NUM>, <NUM>) can increase their rate of pressure sampling. Additionally, the other pressure sensing devices can add their own data set to the data pool <NUM> (e.g., a data pool associated with sensing devices in a geographic area and/or devices within a logical group). The data pool <NUM> may be used to determine if an over-pressure event is area-wide (e.g., caused by events on the distribution side) or if it is localized to the single service point and/or device. Such a collaboration between devices distributed on (or near) the edge of a gas distribution system reduces the chance that decisions will be made based on false positives.

Data from group <NUM> may be sent (e.g., by cellular or internet connection <NUM>) to a headend device. In the example of <FIG>, the data sent to the headend device <NUM> may include an initial notification by one of the gas pressure-measuring devices that a high gas pressure event (e.g., gas pressure over a threshold) has been detected. The measured gas pressure and the threshold may be sent to the headend device. The threshold is relevant at least in that it puts into perspective what the preferred gas pressure is at the location at which the measurement was made. The headend device <NUM> may be a server of a utility company, a third-party contractor of the utility company, or may be another device. In an example, the data <NUM> received from gas pressure-measuring devices and/or groups of such devices may be displayed for the situational-awareness of human operator(s) and/or used in algorithms that are involved in data-gathering, data-processing, and response(s) to gas over-pressure events. Example responses may include damage prevention procedures, such as shutting valves to prevent increases in gas pressure.

<FIG> shows an example gas delivery system <NUM> containing enhancements to the gas delivery system <NUM> seen in <FIG>. In the example, the gas delivery system <NUM> performs data-processing functions that formulate response(s) to gas over-pressure events, and send appropriate commands to initiate the response(s). The responses may address local gas over-pressure events (e.g., detected by a single smart gas metering device) or area-wide gas over-pressure events (e.g., detected by plural smart gas metering devices within a group of devices).

In the example, an algorithm <NUM> (e.g., a "group algorithm") may utilize data from the group data pool <NUM> of <FIG> to determine a response to an over-pressure event seen by: a gas pressure-measuring device from among those in a group; and/or a group of smart gas pressure-measuring devices. The algorithm <NUM> may be based at least in part on the techniques and methods presented in <FIG>.

The group is typically based on a topology of the gas delivery system, and may include pipelines, smart gas meters (e.g., meters with gas pressure-measuring capabilities), other gas pressure gauges, valves, and other devices. The group algorithm <NUM> can consider the rate of pressure increase so that severity and urgency of the issue can be evaluated. If the rate of gas pressure increase is "slower" (e.g., a rate of change that is less than a threshold value), then the devices may provide instructions for an initial mitigating action that includes a service technician dispatched by the utility company. In contrast, if the group of devices (e.g., algorithm <NUM>) determines that the situation is "faster" (e.g., a rate of change that is greater than the threshold value), then immediate mitigating action should be taken. The algorithm may direct the group of devices to perform automatic shutoffs of their own valves, send shutoff commands to valves in other devices around them, send alarms with pressure sampling data to the headend system for utility notification, and send alerting information to customers' cellular phones <NUM> and/or in-home devices <NUM> to warn the end-customer of the safety situation.

<FIG> shows an example gas delivery system <NUM> illustrating data collection, data transmission, and data utilization. A central office <NUM> may be operated by a utility company, a third-party contractor or other entity. The central office may be in communications with networks <NUM>, such as the internet and/or cellular telephone networks, or proprietary networks. In some examples, a router device <NUM> may (optionally) be in communication with a plurality of devices in one or more groups <NUM>, <NUM> of devices of the gas delivery system <NUM>. In the example shown, the first group of devices includes smart gas metering devices <NUM>-<NUM> and the second group of devices <NUM>-<NUM>. Each smart gas metering device may include hardware devices <NUM>. In different examples, the hardware devices <NUM> may include one or more of a gas metering device, a gas pressure sensor, a radio, a processor, a memory device, and/or a gas valve, etc. The devices <NUM> may be configured (e.g., with software) to perform some or all of the edge detection and gas pressure recognition, notification, and mitigation/repair systems and techniques <NUM>.

In some examples of the techniques discussed herein, the methods of operation may be performed by one or more application specific integrated circuits (ASIC) or may be performed by a general-purpose processor utilizing software defined in computer readable media. In the examples and techniques discussed herein, the memory (e.g., the memory device(s) of hardware <NUM>) may comprise computer-readable media and may take the form of volatile memory, such as random-access memory (RAM) and/or non-volatile memory, such as read only memory (ROM) or flash RAM. Computer-readable media devices include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or other data for execution by one or more processors of a computing device. Examples of computer-readable media include, but are not limited to, phase change memory (PRAM), static random-access memory (SRAM), dynamic random-access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to store information for access by a computing device.

As defined herein, computer-readable media does not include transitory media, such as modulated data signals and carrier waves, and/or signals.

<FIG> shows an example method <NUM> of detecting a high gas pressure condition. The method detects high gas pressure situation(s) within a gas delivery system. In an example, a first device (e.g., smart gas metering device) measures gas pressure and determines if that pressure is over a threshold value. If so, the first device sends a message to at least one other device. In an example, the message is sent to device(s) within a group of devices based on gas system topography (e.g., the group of devices are smart metering devices having a common gas supply line). The receiving devices may respond by indicating if they are experiencing a gas over-pressure condition. If so, the gas over-pressure condition is not localized at the first device. Alternatively, the second device(s) may indicate that it/they is/are not in an over-pressure condition, thereby suggesting that the over-pressure condition may be localized to the first device. An appropriate response may be made within the gas delivery system depending on if the over-pressure condition is localized to the first device, or more widely present within the group of devices. In examples, protective measures may be taken, such as closing valves providing gas to appropriate service sites.

At block <NUM>, gas pressure is measured at a device to obtain a first gas pressure value. In the example of <FIG>, the first device may be the smart metering device <NUM>, and may measure gas pressure at a customer's site.

At block <NUM>, it is determined that the first gas pressure value exceeds a first threshold value. In the example, the smart metering device <NUM> may perform the calculation with respect to the first threshold value. In other examples, the calculation may be performed at a headend device or other location. In the example of block <NUM>, in response to determining that the first gas pressure value exceeds the first threshold value, a rate at which gas pressure is measured is increased.

At block <NUM>, at least one of the first gas pressure value, a threshold value, and an indication that the first gas pressure value exceeds the first threshold value is sent from the first device to second device(s). In some examples, the second device(s) to which data is sent are selected from among devices in a group also including the first device. By defining one or more groups of devices, the gas pressure information of one or more group members can be used synergistically to anticipate gas over-pressure events at other group members. In additional examples, the data is sent from the first device to devices selected based on a topology of the gas delivery system (e.g., the device(s) may be selected based on connection to a same gas main), possibly without formally defining groups of devices. In further examples, the data is sent from the first device to device(s) less than a threshold distance from the first device. In still further examples, the data is sent from the first device to device(s) based on one or more of the above examples.

At block <NUM>, information comprising at least one of a second gas pressure value indicating gas pressure at the second device or an indication of whether the second gas pressure value exceeds a second threshold value is received. In a first example, the first device receives the information. In a second example, the information could be received at a headend server or other device at any location.

At block <NUM>, "local" high gas-pressure event may be reported, if high gas pressure was detected only at the first device. In an example, a high gas-pressure event at the device may be based at least in part on the second gas pressure value being at or below the second threshold value. In the example, if the second gas pressure of the second device does not exceed that device's threshold value then only a local high gas-pressure event at the first device is reported.

At block <NUM>, a "group-wide" high gas-pressure event may be reported, if high gas pressure was detected at the first device and at the second device(s). In an example, a high gas-pressure event within a distribution area of the device and the second device is reported (e.g., to a headend device and/or to all devices within the group) based at least in part on the second gas pressure value (at the second device) exceeding the second threshold value (which may or may not be the same as the first threshold value).

At block <NUM>, a high gas-pressure event may be anticipated because the rate of gas pressure increase is high at any device, even if the gas pressure has not yet exceeded a threshold value. In an example, it may be determined that a rate of gas pressure increase (e.g., at the first device or second device) exceeds a third threshold value. When the rate of gas pressure increase is high (even if the actual gas pressure has not yet exceeded a threshold value) it may be important to realize that the gas pressure is changing fast (i.e., increasing), that an over-pressure event may happen soon, and that protective measures should be taken even before high gas pressure thresholds are exceeded.

At block <NUM>, a first gas valve of the first device is closed based at least in part on the high gas-pressure event at the first device. In an example, the first gas valve may be closed in response to a local high gas-pressure event. In the example of block <NUM>, gas valves at additional devices may be closed based on gas pressure exceeding respective thresholds of the additional devices. In an example, the second gas valve of the second device (e.g., the device discussed at block <NUM>) may be closed in response to a high gas-pressure event at that device. In the example of block <NUM>, devices within a group of devices are notified and/or directed to close their respective gas valves. In an example, this direction may be in response to high gas-pressure events at the first and second devices. Because the group of devices is based at least in part on the topology of the gas delivery system, all devices in the group may be under a high gas-pressure condition, and closing some or all of the gas valves within the group may be indicated.

<FIG> shows example techniques <NUM> for selecting a second device to which to send a message. At block <NUM> of <FIG>, information was sent from the first device (which recognized a gas over-pressure event at its location) to one or more other devices. In an example, the device sensing an over-pressure event attempts to determine if the over gas-pressure condition is limited in extent (e.g., limited to itself), or more broadly includes other devices. The techniques <NUM> include two examples, which may be used singly or in combination, to determine to which device(s) a first device that senses an over-pressure event should send over-pressure information and send a request (explicit or implied) for the receiving device to perform tasks, such as measuring gas pressure, increasing a frequency or rate of such measurements, comparing measurements to thresholds, and/or taking actions to lessen/prevent damage from a high gas pressure event. In some examples, if the first device sends its gas pressure information to one or more other devices, those device(s) may assume that the first device is experiencing an over-pressure event (i.e., the over-pressure event at the first device is why the message was sent). In other examples, if a threshold value is also sent by the first device, the second device(s) may readily determine the amount by which measured gas pressure at the first device exceeded a threshold of the first device.

At block <NUM>, second device(s)-to which the first device may send gas pressure and/or threshold value information-may be selected from among a plurality of devices. In some examples, the selecting is based at least in part on data describing aspects of a topology of a gas delivery system to which the first device and the second device are connected, and wherein the selecting is performed prior to the sending. In some examples, the selecting is based at least in part on a distance between the first and second devices. If the distance between the first device and other devices is less than a threshold distance, the first device may send gas pressure and/or threshold value information to those devices.

At block <NUM>, an RF signal strength of a signal sent by the second device is measured. The signal strength of the second device, measured at the first device, helps the first device determine a distance to the second device. The second device may be selected from among a plurality of devices based at least in part on the measured RF signal strength of each respective device from among the plurality of devices. In an example, a device is selected based on which device(s) appear to be closer to the first device, or which device(s) are less than a threshold distance from the first device.

<FIG> shows example techniques <NUM> for responding to a high gas pressure condition. The techniques <NUM> include two examples, which may be used singly or in combination, to mitigate or prevent damage to the gas supply system and/or customers' appliances and infrastructure that might otherwise result in an over-pressure event. In some examples, a valve is closed on a single device to prevent additional gas from entering a part of the gas delivery system, which would further increase the gas pressure. In other examples, valves are closed on multiple devices to prevent such damage.

At block <NUM>, based at least in part on the second gas pressure value exceeding the second threshold value, a shutdown command is sent to a group of devices. In an example, each device in the group of devices is connected to a gas main to which the device is connected or is within a threshold distance of the device.

At block <NUM>, based at least in part on the second gas pressure value exceeding the second threshold value, a supply of gas to a region within a gas distribution system is shut off. In an example, the region includes the device and the second device. In a further example, the region includes all devices (e.g., smart gas meters) attached to a same gas delivery pipe. In a further example, the region includes all devices within a group of devices, and the group is defined based at least on a database containing a topological description of the gas delivery system. The topological description of the gas delivery system may include a listing of devices in the system, their characteristics, and how, when, where, and/or to what they are connected.

<FIG> shows additional example techniques <NUM> for responding to a high gas pressure condition. The techniques <NUM> include three examples <NUM>-<NUM>, which may be used singly or in one or more combinations, to send messages to devices (e.g., cellular devices, in-home devices, headend devices, etc.). The messages may be sent in response to a first device detecting over-pressure gas conditions or a second device that checked gas pressure conditions responsive to message(s) from the first device.

At block <NUM>, a message may be sent to a first cellular phone or to a first in-home device associated with the first device (e.g., a smart gas meter). The message may warn the recipient of an over-pressure event, and may suggest a course of action (such as evacuation of the property). In a variation of block <NUM>, the message may be sent to authorities (e.g., <NUM>, emergency, the fire department, etc.). The message may include the nature of the over-pressure event, the address(es) of the event, a suggested course of action, etc..

At block <NUM>, the message (or a similar message) may be sent to a second cellular telephone or to a second in-home device associated with a service site within a threshold distance of the first device. Messages (e.g., warnings) may be sent to additional service sites if the over-pressure event does not appear to be limited to a single service site.

At block <NUM>, the message (or a similar message) may be sent to a headend device, based at least in part on at least one condition being true, the conditions including: the first gas pressure value exceeds the first threshold value; and the second gas pressure value exceeds the second threshold value.

<FIG> shows example techniques <NUM> for defining and using groups of devices, detection of a gas over-pressure condition, and reporting the over-pressure event affecting the group of devices. The techniques <NUM> include grouping devices based at least in part on gas system topography, determining that gas-pressure threshold(s) have been exceeded at one or more devices in a group of devices, and reporting gas over-pressure events in messages and/or warnings to users and/or authorities (e.g., <NUM>). The reporting may be based at least in part on the group associated with the device(s) found to have over-pressure events. By recognizing common features of devices and grouping them, the reporting can include devices that are in danger of an over-pressure event but may not have even realized the situation. The failure to realize the situation may result from a frequency of gas pressure measurement. Accordingly, the use of groups leverages the measurements of one device (e.g., smart gas meter) to protect the service site of another device.

At block <NUM>, a group of devices is defined based at least in part on a topology of a gas delivery system. In an example, the topology may be used to organize the group based on some or all devices related to, or attached to, a gas pipeline serving a number of customer sites. In a further example, each device of the group may be within a threshold distance of all other devices of the group. The devices may include a gas source (e.g., an LNG plant), a pipeline, a number of smart gas meters, gas valves, in-home devices, etc..

At block <NUM>, it is determined that gas pressure measurements exceed respective thresholds at one or more devices within the group of devices. The number of devices with gas pressure that is over-pressure may be compared to a third threshold, such as to reduce false positives. In an example, one device measures gas pressure over a threshold and alerts other device(s) to measure their gas pressure and/or increase a frequency of gas pressure measurements.

At block <NUM>, an over-pressure event that affects the group of devices is reported. The over-pressure event may be reported by one or more smart gas meters or other devices. The over-pressure event may be reported to the customer(s) at affected sites, including reports made to in-home devices, cellular telephones, etc. Reports may be sent to customer(s) at sites that are geographically near the affected sites. Alternatively, or additionally, reports may be sent to customer(s) at sites that are related to site(s) detecting the over-pressure event by aspects of the topology of the gas delivery system. For example, the aspects of the topology may include sites served by a same gas main, sites served by a same gas supply facility, sites having gas flow affected by same valve(s), etc..

If pressure in an area of a gas distribution system gets too high, it can cause pipe bursting, gas venting, enlarged and unsafe pilot lights, and possibly fires and explosions. Gas flows from higher pressures upstream to lower pressures downstream. Additionally, the gas pressure within a gas delivery system can vary from city gate regulators and meters in the system to the end service point regulators and meters. Example factors governing pressure drop include the length of runs (e.g., the length of gas mains), number of pipe bends and joints, and internal gas against pipe friction. By monitoring pressure at a plurality of points, the system increases the ability for utility companies to anticipate, detect and/or mitigate unsafe situations, and avoid unsafe situations with network latencies, headend application latencies, and human delays. The systems and techniques (e.g., smarter gas metering devices) at service points provide the means to self-monitor for unsafe situations. In some examples, the systems and techniques also monitor not only at the single point at which the equipment is installed, but also an area surrounding the location of the equipment. In the example, such monitoring is performed by exchanging information with smart metering devices at nearby service sites. In many examples, the gas delivery system performs actions that automatically mitigate unsafe situation(s).

Devices with pressure sensors (e.g., smart gas metering devices, etc.) can periodically compare their pressure readings to one or more high gas-pressure threshold values. If a device detects that pressure has passed one of the thresholds it can increase the rate of its pressure sampling and can send its latest pressure readings and thresholds to its neighboring devices that also have pressure sensors. The other pressure sensing devices can likewise increase their rate of pressure sampling and add their own data set to a group data pool (e.g., a data pool associated with sensing devices in a logical group defined according to a geographic area, according to pipelines, and/or according to a gas supply topology). The data pool may be used to determine if an over-pressure event is area-wide (e.g., caused by events on the distribution side) or if it is localized to the single service point and/or device. Such a collaboration between devices distributed on (or near) the edge of a gas distribution system reduces the chance that decisions will be made based on false positives.

The group algorithm can consider the rate of pressure increase so that severity and urgency of the issue can be evaluated. If the rate of gas pressure increase is "slow," the devices may provide instructions for an initial mitigating action that includes a service technician dispatched by the utility company. In contrast, if the group of devices determines that the situation is real, urgent, and that immediate mitigating action needs to take place, the group of devices can perform automatic shutoffs of their own valves, send shutoff commands to valves in other devices around them, send alarms with pressure sampling data to the headend system for utility notification, and send information to in-home devices to warn the end-customer of the safety situation.

The logic that controls actions of the gas delivery system (e.g., that controls points to shut off) relies on knowledge of the distribution system service point connections and location of regulators and/or gate valves that "segment" portions of that distribution system. Additionally, the physical distance between service points may be considered even if they are not on the same distribution line. Devices can know their group (or groups) via pre-programming (e.g., programming at time of manufacture), programming at install time, self-discovery, and/or by hearing network radio frequency (RF) messages. In other examples, devices can be configured to be within one or more groups via network or local communication based on distribution topology.

In some examples, the logic that controls actions of the gas delivery system can be based at least in part on a topology of the gas delivery system. The topology may include all the gas supply facilities, gas pipes, valves, gas meters and other devices used in gas supply. An augmented topology may include communications devices, such as radios that allows control circuits to operate the gas delivery devices (e.g., valves). The topology of the gas delivery system (with or without augmentation to include communications devices) may be instantiated in a database or other data structure.

In different examples, the techniques discussed herein could additionally and/or alternatively be applied to low-pressure situations in a gas distribution system. The low-pressure conditions are not as urgent as high-pressure conditions, but can help mitigate loss of pressure in a system which can lead to pilot lights going out and costly re-lighting processes.

Claim 1:
A method (<NUM>), comprising:
measuring (<NUM>) gas pressure at a first device to obtain a first gas pressure value;
determining (<NUM>) that the first gas pressure value exceeds a first threshold value;
sending (<NUM>) at least one of the first gas pressure value or an indication that the first gas pressure value exceeds the first threshold value to a second device;
receiving (<NUM>) information comprising at least one of a second gas pressure value indicating gas pressure at the second device or an indication of whether the second gas pressure value exceeds a second threshold value;
reporting (<NUM>) at least one of:
a high gas-pressure event at the first device based at least in part on the second gas pressure value being at or below the second threshold value; or
a high gas-pressure event within a distribution area comprising the first device and the second device based at least in part on the second gas pressure value exceeding the second threshold value; and
responsive to determining that the first gas pressure value exceeds the first threshold value, closing (<NUM>) a valve of the first device.