Apparatuses and methods for improved switchgear sensor data communication
Devices, systems and methods are provided to improve communication of switch sensor and status signals between a medium voltage overheard switchgear and an intelligent electronic device (IED). A switchgear interface device is deployed proximally to a switchgear and/or junction box situated at a distal end of a utility pole. The switchgear interface device (SID) receives, processes and combines sensor signals and status signals from switches in the switchgear with metadata for transport as digital signals to an IED mounted at the other end of the utility pole. The cabling for sensor and status signals between the SID and the IED can be fiber or Ethernet. The digital signals can be formatted using the IEC61850 standard. The SID can have drive electronics and send open and close command signals to the switches to eliminate the need for a multi-pin connector cable for transport of switch power signals from the IED.
1 . A method of communication between a medium voltage overheard switchgear and an intelligent electronic device (IED), the switchgear mounted on a distal end of a utility pole and connected to an electric power distribution line, the utility pole having a proximal end secured to a ground support and the IED secured at the proximal end, the switchgear having sensors at a switch provided at one of three phase conductors associated with the power distribution line, the method comprising:
receiving analog signals providing representations of current and voltage measured by the sensors at the switch, and at least one status signal indicating one of an opened status and closed status of the switch;
digitizing the analog signals to generate corresponding digital inputs therefrom;
sampling the digital inputs to obtain samples;
combining the samples into a set of merged digital samples having a designated format and comprising digital representations of the current or voltage of a corresponding one of the phase conductors measured by the sensors, the status signal, and metadata, the metadata chosen from identification of which of the sensors that the digital samples originated from, identification of the switch, at least one of identification and location data of the switchgear,
performing the receiving, digitizing, sampling and combining via one or more components at a switchgear interface device located proximally to the switch and the distal end of the utility pole; and
providing the merged digital samples and the metadata as outputs to a digital data connector located at the switchgear interface device and configured to be connected to a digital data cable.
2 . The method of claim 1 , further comprising connecting a digital data cable between the digital data connector and the IED, the digital data cable chosen from an optical fiber cable and an Ethernet cable, and the digital data connector chosen from a fiber cable connector and an Ethernet cable connector that corresponds to the digital data cable.
3 . The method of claim 1 , wherein combining the samples comprises formatting the merged digital samples using an IEC61850 standard from International Electrotechnical Commission (IEC).
4 . The method of claim 3 , wherein combining the samples comprises:
formatting the merged digital samples using an IEC61850-9-2 protocol chosen from the IEC61850 standard, the merged digital samples being encoded in multicast Ethernet frames; and
transmitting the merged digital samples unacknowledged data from the switchgear interface device operating as a publisher in accordance with the IEC61850-9-2 protocol to subscribers comprising the IED.
5 . The method of claim 3 , wherein combining the samples further comprises providing global positioning system (GPS) time synchronization to the merged digital samples.
6 . A switchgear interface device for a medium voltage overhead switchgear mounted on a distal end of a utility pole and connected to an electric power distribution line, the utility pole having a proximal end secured to a ground support and a cabinet with an intelligent electronic device (IED) secured at the proximal end, the switchgear having sensors at a switch provided at one of three phase conductors associated with the power distribution line, a switchgear interface device comprising:
a housing configured to be disposed adjacent the switchgear and mounted on the distal end of the utility pole;
a plurality of inputs at the housing configured to receive analog signals providing representations of current or voltage measured by the sensors at the switch, and to receive at least one status signal indicating one of an opened and closed status of the switch;
a processor disposed within the housing and configured to digitize the analog signals and the at least one status signal to generate corresponding digital inputs therefrom, sample the digital inputs to obtain samples, and combine the samples into a set of merged digital samples having a designated format and comprising digital representations of the current and voltage of a corresponding one of the phase conductors measured by the sensors, the status signal, and metadata, the metadata chosen from identification of which of the sensors that the digital samples originated from, identification of the switch, at least one of identification and location data of the switchgear;
a memory disposed within the housing and configured to store the set of merged digital samples; and
a digital data connector connected to the housing and configured to be connected to a digital data cable chosen from an optical fiber cable and an Ethernet cable and to provide the merged digital samples and the metadata as outputs to the digital data cable and the IED when the digital data cable connects the digital data connector and the IED, the digital data connector chosen from a fiber cable connector and an Ethernet cable connector that corresponds to the digital data cable.
7 . The switchgear interface device of claim 6 , further comprising drive electronics and an energy storage device to power the drive electronics, the processor configured to receive at the digital data connector a switch command signal transmitted from the IED via the digital data cable and to operate the drive electronics to send a switch power signal to the switch to open or close in accordance with the switch command signal.
8 . The switchgear interface device of claim 6 , further comprising:
a switch power signals connector connected to the housing and configured to be connected to a second cable separate from the digital data cable and to receive switch power signals comprising a close to open signal and an open to close signal for the switch from the IED via the second cable when the second cable connects the switch power signals connector and the IED, the switch power signals connector comprising a plurality of connector inputs chosen from at least one of pins and receptacles and that each provide a corresponding one of the switch power signals to a terminal block in the housing that is electrically connected to a switch actuation mechanism in the switch.
9 . The switchgear interface device of claim 6 , wherein the designated format of the set of merged digital samples is an IEC61850 standard from International Electrotechnical Commission (IEC).
10 . The switchgear interface device of claim 9 , wherein the processor is configured to employ an IEC61850-9-2 protocol chosen from the IEC61850 standard wherein the processor operates as a publisher and transmits unacknowledged data to subscribers comprising the IED, the unacknowledged data comprising the merged digital samples encoded in multicast Ethernet frames.
11 . The switchgear interface device of claim 9 , wherein the processor is configured to employ global positioning system (GPS) time synchronization of the merged digital samples.
12 . The switchgear interface device of claim 6 , the switchgear having a second switch and a third switch provided respectively at the other two of the three phase conductors, wherein
the plurality of inputs at the housing are configured to receive analog signals providing representations of current or voltage measured by sensors provided at each of the second switch and the third switch, and to receive status signals indicating one of an opened and closed status of the second switch and the third switch; and
the processor is configured to digitize the analog signals and the status signals from the second switch and the third switch to generate corresponding digital inputs therefrom, sample the digital inputs and combine the samples into the set of merged digital samples having the designated format such that the set of merged digital samples generated by the processor further comprises digital representations of the current and voltage of the other two of the phase conductors measured by a corresponding one of the sensors, the status signals of each of the switches at the other two of the phase conductors, and the metadata corresponding to the second switch and the third switch and the sensors for the other two of the phase conductors.
13 . A switchgear interface device for a medium voltage overhead switchgear mounted on a distal end of a utility pole and connected to an electric power distribution line, the utility pole having a proximal end secured to a ground support and a cabinet with an intelligent electronic device (IED) secured at the proximal end, the switchgear having sensors at a switch provided at one of three phase conductors associated with the power distribution line, the switchgear disposed adjacent to a junction box at the distal end of the utility pole, a switchgear interface device (SID) comprising:
switch SID components arranged proximally to and electrically connected to the switch, the switch SID components comprising
a processor configured to receive analog signals from the sensors that are representations of current or voltage measured by the sensors at the switch, and at least one status signal indicating one of an opened status and a closed status of the switch, digitize the analog signals and the at least one status signal to generate corresponding digital outputs therefrom, sample the digital outputs to obtain samples, and combine the samples into a set of merged digital samples having a designated format and comprising digital representations of the current and voltage of a corresponding one of the phase conductors measured by the sensors, the status signal, and metadata, the metadata chosen from identification of which of the sensors that the digital samples originated from, identification of the switch, at least one of identification and location data of the switchgear;
a memory configured to store the set of merged digital samples; and
a digital data connector configured to be connected to a digital data cable chosen from an optical fiber cable and an Ethernet cable and to provide the merged digital samples and the metadata to the junction box when the digital data cable connects the digital data connector and the junction box, the digital data connector chosen from a fiber cable connector and an Ethernet cable connector that corresponds to the digital data cable.
14 . The switchgear interface device of claim 13 , further comprising:
a second digital data connector mounted on the junction box and configured to be connected to the digital data cable and to receive the merged digital samples and the metadata from the switch SID components when the digital data cable connects the digital data connector and the second digital data connector on the junction box;
a third digital data connector connected to the junction box and configured to be connected to a second digital data cable chosen from an optical fiber cable and an Ethernet cable and to provide the merged digital samples and the metadata as outputs to the second digital data cable and the IED when the second digital data cable connects the third digital data connector and the IED, the third digital data connector chosen from a fiber cable connector and an Ethernet cable connector that corresponds to the second digital data cable; and
a communications hub provided in the junction box and having a plurality of ports and configured to provide signals received at one of the ports to one or more of the other ones of the plurality of ports, the second digital data connector and the third digital data connector connected to a respective one of two of the plurality of ports, the communications hub being operable to provide the merged digital samples and the metadata received at the second digital data connector to the third digital data connector.
15 . The switchgear interface device of claim 14 , further comprising:
drive electronics in the junction box and an energy storage device in the junction box to power the drive electronics; and
a multi-pin connector at each of the junction box and switch that interfaces with a switch power signals cable that is separate from the digital data cable, the multi-pin connector at the switch being electrically connected to an actuation mechanism for the switch, and the multi-pin connector at the junction box being electrically connected to the drive electronics;
wherein the processor is configured to receive at the digital data connector a switch command signal transmitted from the IED via the communications hub, the second digital data cable, and the digital data cable, and to send a control signal to the drive electronics via the digital data cable to operate the drive electronics to send a switch power signal to the switch to open or close in accordance with the switch command signal; and
wherein the switch power signals cable transmits the switch power signal to the switch.
16 . The switchgear interface device of claim 13 , wherein the designated format of the set of merged digital samples is an IEC61850 standard from International Electrotechnical Commission (IEC).
17 . The switchgear interface device of claim 16 , wherein the processor is configured to employ an IEC61850-9-2 protocol from the IEC wherein the processor operates as a publisher and transmits unacknowledged data to subscribers comprising the IED, the unacknowledged data comprising the merged digital samples encoded in multicast Ethernet frames.
18 . The switchgear interface device of claim 16 , wherein the processor is configured to employ global positioning system (GPS) time synchronization of the merged digital samples.
19 . The switchgear interface device of claim 13 , wherein the switchgear comprises a second switch provided at the other two of the three phase conductors, and the switchgear interface device further comprises a second electronic circuit arranged proximally to the second switch, the second electronic circuit comprising:
a second processor configured to receive analog signals that are representations of current or voltage measured by sensors at the second switch, and at least one status signal indicating one of an opened status and a closed status of the second switch, to digitize the analog signals and the at least one status signal corresponding to the second switch to generate corresponding digital outputs therefrom, to sample the digital outputs of the second switch to obtain samples; and
a second memory configured to store the samples of the second switch.
20 . The switchgear interface device of claim 19 , wherein the processor comprises a data conversion and combining device that is configured to
combine the stored samples from the second switch into a second set of merged digital samples having the designated format and comprising digital representations of the current and voltage measured at the second switch, at least one status signal corresponding to the second switch, and second metadata chosen from identification of which of the sensors at the second switch that the digital samples originated from, identification of the second switch, and at least one of identification and location data of the switchgear; and
combine the set of merged digital samples and the second set of merged digital samples and provide the combined samples to the junction box via the digital data connector.