DISTRIBUTED ENERGY RESOURCES COMMUNICATIONS NETWORK AND CONTROL SYSTEM

Abstract

A method and system for a distributed communications and control network that manages Distributed Energy Resources (DER) on a power utility grid. Such a network uses a three-tiered network architecture (FIG. 2) named DERCOM comprised of two or three components:

E-DERM An edge DER module (required)

D-DERM A distributed DER module (required)

C-DERM A centralized DER module (optional). The DERCOM network can begin as D-DERM/E-DERM installations (FIG. 3; FIG. 4) which can later integrate with an existing or future centralized C-DERM deployment. The E-DERM module being an edge device, physically located at each DER Point of Common Coupling (PCC), provides communications and protocol translations between DER and utility grid over wired or wireless connections. The E-DERM may also be located at utility device locations to control such devices. E-DERM communicates with D-DERM. The D-DERM module being a distributed system controller, physically located at the utility substation and managing multiple DER sites via E-DERM devices, on a circuit and substation aggregate basis. A D-DERM hosts multiple algorithms providing various grid optimization applications. The D-DERM may also manage non-DER utility devices for distribution automation and demand response applications. D-DERM communicates with E-DERM and C-DERM. The C-DERM module being a management software application typically located at a regional utility control center. The C-DERM communicates with one or many D-DERM substation controllers to implement broad overall control strategies. DERCOM provides the four fundamental roles of a DERM system:

Aggregate: Aggregates the services of many individual DER and presents them as a smaller, more manageable, number of aggregated virtual resources

Simplify: Handles the granular details of DER settings and presents simple grid-related services

Optimize: Optimizes the utilization of DER within various groups to get the desired outcome at minimal cost and maximum power quality

Translate: Translates individual DER languages, and presents to the upstream calling entity in a cohesive way.

Claims

1. A system for a distributed communications and control network that manages Distributed Energy Resources (DER) on a power utility grid, using a three-tiered network architecture DERCOM comprising two or three components; namely: E-DERM—An edge DER module (required); D-DERM—A distributed DER module (required); C-DERM—A centralized DER module (optional); wherein the DERCOM network can begin as D-DERM/E-DERM installations, such as shown in FIGS. 3 and 4, which can later integrate with an existing or future centralized C-DERM deployment; the E-DERM module, being an edge device, is physically located at each DER Point of Common Coupling (PCC), providing communications and protocol translations between DER and utility grid over wired or wireless connections, wherein the E-DERM may also be located at utility device (e.g. voltage regulator or capacitor bank) locations to control such devices; E-DERM communicates with D-DERM; wherein the D-DERM module, being a distributed system controller, is typically located at the utility substation and manages multiple DER sites via E-DERM devices, on a circuit and substation aggregate basis. The D-DERM can also be located outside a substation if load and generation inputs can be brought in to it; wherein a D-DERM hosts multiple algorithms providing various grid optimization applications; wherein the D-DERM may also manage non-DER utility devices for distribution automation and demand response applications. D-DERM communicates with E-DERM and C-DERM; wherein the C-DERM module, being a management software application, is typically located at a regional utility control center, where the C-DERM communicates with one or many D-DERM substation controllers to implement broad overall control strategies; and wherein DERCOM provides four fundamental roles of a DERM system; namely, Aggregate: Aggregates the services of many individual DER and presents them as a smaller, more manageable, number of aggregated virtual resources, Simplify: Handles the granular details of DER settings and presents simple grid-related services, Optimize: Optimizes the utilization of DER within various groups to get the desired outcome at minimal cost and maximum power quality, and Translate: Translates individual DER languages, and presents to the upstream calling entity in a cohesive way.

2. The DERCOM system according to claim 1, using redundant communication channels in various configurations for higher availability and enhanced security, where communication media include wired, wireless, and powerline communications such as shown in FIGS. 3 and 4, and wherein E-DERM/D-DERM communications can take a variety of forms, including: Two way over an external link (e.g. fiber, wireless, cellular) PLC for outgoing and external link for incoming PLC for outgoing only (one-way implementation) Two way over an external link (e.g. fiber, wireless, cellular) with PLC supervision, or Combinations of the above, and the PLC signal may also be used to monitor circuit continuity, providing unintentional islanding (UI) protection as done by GridEdge DGP.

3. The DERCOM system according to claim 1, allowing for a scalable and cost-effective way to manage multiple DER on a utility network.

4. The DERCOM system according to claim 1, using IEEE 1547-2018 approved communications protocols and IEEE 1547.1-2020 DER commands.

5. The DERCOM system according to claim 4, enabling DER grid support applications in compliance with IEEE 1547-2018, including typical DER grid support applications; namely, Intelligent Volt-Watt Control Reactive Power/Power Factor Low Voltage Ride Through Load and Generation Following Storage Systems Charge/Discharge Management Connect/Disconnect Dynamic reactive Current Injection (responding to change in voltage) Max Generation Limiting Intelligent Frequency-Watt Control Peak Limiting Function for Remote Points of Reference DER Protection—Island Detection and Grid Disconnects; Steady State Operation in islanded Mode DER Load Balancing—Maintains L/G Ratio by Curtailing DER Output 3V0 protection—Avoids Backflow through Transformer onto High Side ESS Charging Control—Controls Charging Parameters of Energy Storage and ESS Frequency Regulation—Regulates Power Frequency

6. A closed-loop control software algorithm that monitors and manages station generation/load ratio in real time and uses the DERCOM system according to claim 1, such as shown in FIG. 5, wherein the closed-loop control software is implemented in the D-DERM station controller.

7. A closed-loop control software algorithm according to claim 6, that uses a DERCOM network such as shown in FIG. 6, having a begin main control loop for each station, including, a. For each DER: Input to E-DERM the real time Generation (PGn: output power in Watts) and send reading to D-DERM b. Input to D-DERM, the real time power outflow from station (PS) c. Calculate in D-DERM the total Load (PS+PG1+PG2+ . . . ) d. Compare Generation to Load (G/L) ratio to factor K (typically: K=0.77) e. If G/L is greater than K, proceed to curtail DER output power by 10%; otherwise go to step a f. D-DERM send power curtailment command to DER via E-DERM g. Wait T seconds (default value: T=1) h. Send configuration information request command to curtailed DER i. Verify that DER changed its maximum output power limit to 90% of previous value; if DER didn't change its value, trip the DER j. Enter new limit in local D-DERM data base k. Wait L seconds (default value: L=5) l. Go to step a. End control loop

8. The closed-loop control system according to claim 6, used to avoid substation transformer backfeed into the utility transmission system and expanded to optimize circuit hosting capacity, eliminate the need for substation 3V0 protection, provide adaptive relay settings and enable other grid support applications.

9. The DERCOM system according to claim 1, used for Front of The Meter (FTM) and Behind the Meter (BTM) applications. where E-DERM devices connect to FTM or BTM sources and loads which can then be managed, and where the connection may be via wired, wireless, powerline or other means.

10. The DERCOM system according to claim 1, integrated with a GridEdge Distributed Generation Permissive (DGP) system such as shown in FIG. 4, where commands sent via DGP are highly cyber-secure, and where DGP communications may take a variety of forms: PLC for outgoing and external link for incoming PLC for outgoing only (one-way implementation) Two way over an external link with PLC supervision.

11. The DERCOM-DGP system according to claim 10 providing unintentional islanding protection, along with multiple DER grid support applications, thereby providing an all-in-one solution to grid optimization, including, Intelligent Volt-Watt Control Reactive Power/Power Factor Low Voltage Ride Through Load and Generation Following Storage Systems Charge/Discharge Management Connect/Disconnect Dynamic reactive Current Injection (responding to change in voltage) Max Generation Limiting Intelligent Frequency-Watt Control Peak Limiting Function for Remote Points of Reference DER Protection—Island Detection and Grid Disconnects; Steady State Operation in islanded Mode DER Load Balancing—Maintains L/G Ratio by Curtailing DER Output 3V0 protection—Avoids Backflow through Transformer onto High Side ESS Charging Control—Controls Charging Parameters of Energy Storage and ESS Frequency Regulation—Regulates Power Frequency, and where DER commands can be embedded within the UI permissive signal.

12. The DERCOM-DGP system according to claim 11 along with the closed-loop control software algorithm according to claim 6, such as shown in FIG. 5.

13. The DERCOM-DGP system according to claim 11 along with the following control algorithm; namely, where the DERCOM-DGP system provides unintentional islanding protection and uses one-way powerline communications in lieu of a two- way external channel so that while less accurate than a two-way communications implementation, it provides a conservative way to limit the G/L ratio, using nameplate generation data rather than actual real time generation, and where for each DER on the station, the D-DERM shall: a. Store all DER nameplate information in D-DERM database b. Calculate approximate total station generation using sum of DER nameplate information c. Calculate approximate station load using sum of DER nameplate information and real time station outflow readings d. Calculate approximate station generation/load ratio (R) using results from b and c e. Compare R to allowable limit K f. Establish control link with DER Send a permissive signal when DER is allowed to export power Stop the permissive signal when DER is not permitted to export power Send a digitally encoded token to the E-DERM to enable sending a command to the DER g. If R>K, send a digitally encoded token to the E-DERM to curtail output power by 10% h. If station outflow does not immediately increase due to DER curtailment, D-DERM disconnects the DER from the grid by stopping the permissive signal i. Enter new curtailed generation value into nameplate data base (zero if DER tripped in step h), replacing previous value j. Go to b; and where the permissive commands are embedded within the DGP UI signal.

14. The system according to claim 13 providing compliance with, and utilization of, the IEEE 1547-2018 and IEEE 1547.1-2020 standards.

15. The system according to claim 1 used for monitoring and managing non-DER utility assets for other applications such as distribution automation and demand response.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings illustrate embodiments of the invention and, together with the general description given above, serve to explain the method and system for a Distributed Energy Resources Communications Network and Control System (DERCOM).

[0058] FIG. 1 depicts a section of the power grid with DER deployments on circuits emanating from the utility substation. There is no communication between the utility grid and DER. The DER simply connects or disconnects from the grid based on local connection conditions. There are no provisions for DER grid support functions. FIG. 2 depicts the same section of the power grid with a DERCOM network providing direct communications and control between the utility (or another authorized agency) and DER. The DERCOM network uses D-DERM substation controllers (red boxes) and E-DERM edge devices at each DER location (blue boxes). The E-DERM may also interface with other utility devices. An optional C-DERM software resides at the utility control center. This C-DERM may optimize the operation of multiple D-DERM.

[0059] FIG. 3 depicts a field deployment of a basic DERCOM network between a distribution substation and a single DER. This configuration has a D-DERM controller located at the substation and an E-DERM edge device located at the point of common coupling of the DER. The communications between the D-DERM and the E-DERM is point-to-point and can use various secured wired and wireless media options. The D-DERM communicates to other devices inside the substation using DNP3 protocol and the E-DERM communicates to the DER over short wired or wireless hops using one of the three IEEE approved protocols. Future communications between D-DERM and C-DERM is supported.

[0060] FIG. 4 depicts a DERCOM-DGP network and its capabilities. DGP signaling over the power line provides 100% dependable UI protection as well as selected communications backup and related control signals. Primary D-DERM/E-DERM communications is conducted over external (wired or wireless) redundant channels. Upon loss of the external communications network, the system defaults to using the powerlines for basic functions such as fixed size power curtailment and permit service. Another embodiment uses the powerline signal to send commands and an external channel for feedback. This is a highly secure mode of operation.

[0061] FIG. 5 depicts an example of the implementation of a closed-loop control algorithm used for optimizing grid operation on every circuit in a region by changing DER settings and monitoring their effect in real time. This concept also supports the creation of virtual power plants (VPP). The same concept can also be extended to non-DER devices such as voltage regulators and capacitor banks, EV charging stations, and other loads. This represents a full three tier DERCOM configuration.

[0062] FIG. 6 depicts an implementation of a closed-loop control algorithm used for power control of DER to maintain a desired generation/load ratio. The software algorithm inside the D-DERM controller continuously receives Load and Generation inputs and makes DER output power decisions in real time. The control commands are sent from the D-DERM in the substation to the DER's via the E-DERM edge devices.

[0063] The E-DERM devices use secure communication channels to send back Generation readings from the DER PCC location (Point of Common Coupling). The DERCOM-DGP system uses the powerlines to send a permissive signal to protect against unintentional islanding. It also serves as a partial backup when the DERCOM primary communication channels are not available (as a highly secure one-way communications path). This can be thought of as an equivalent to a computer “safe mode ”.

BEST MODE FOR CARRYING OUT THE INVENTION

[0064] The present invention can be implemented in various different embodiments, such as (but not limited to) the embodiments described below:

First Embodiment

[0065] A method and system for a distributed communications and control network that manages Distributed Energy Resources (DER) on a power utility grid. Such network using a three-tiered network architecture (FIG. 2) named DERCOM comprised of two or three components: [0066] a. E-DERM—An edge DER module (required) [0067] b. D-DERM—A distributed DER module (required) [0068] c. C-DERM—A centralized DER module (optional)
The DERCOM network can begin as D-DERM/E-DERM installations (FIG. 3; FIG. 4) which can later integrate with an existing or future centralized C-DERM deployment.

[0069] The E-DERM module being an edge device, physically located at each DER Point of Common Coupling (PCC), providing communications and protocol translations between DER and utility grid over wired or wireless connections. The E-DERM may also be located at utility device (e.g. voltage regulator or capacitor bank) locations to control such devices. E-DERM communicates with D-DERM.

[0070] The D-DERM module being a distributed system controller, physically located at the utility substation and managing multiple DER sites via E-DERM devices, on a circuit and substation aggregate basis. A D-DERM hosts multiple algorithms providing various grid optimization applications. The D-DERM may also manage non-DER utility devices for distribution automation and demand response applications. D-DERM communicates with E-DERM and C-DERM.

[0071] The C-DERM module being a management software application typically located at a regional utility control center. The C-DERM communicates with one or many D-DERM substation controllers to implement broad overall control strategies.

DERCOM provides the four fundamental roles of a DERM system: [0072] 1. Aggregate: Aggregates the services of many individual DER and presents them as a smaller, more manageable, number of aggregated virtual resources [0073] 2. Simplify: Handles the granular details of DER settings and presents simple grid-related services [0074] 3. Optimize: Optimizes the utilization of DER within various groups to get the desired outcome at minimal cost and maximum power quality [0075] 4) Translate: Translates individual DER languages, and presents to the upstream calling entity in a cohesive way.

Second Embodiment

[0076] The DERCOM network and system in the first embodiment using redundant communication channels in various configurations for higher availability and enhanced security. Communication media include wired, wireless, and powerline communications (FIG. 3; FIG. 4).

E-DERM/D-DERM communications can take a variety of forms, including: [0077] Two way over an external communications link (e.g. fiber, wireless, cellular, other) [0078] PLC for outgoing and external link for incoming [0079] PLC for outgoing only (one-way implementation) [0080] Two way over an external link (e.g. fiber, wireless, cellular) with PLC supervision [0081] Combinations of the above
The PLC signal may also be used to monitor circuit continuity, providing unintentional islanding (UI) protection as done by GridEdge DGP.

Third Embodiment

[0082] The DERCOM network and system in the first embodiment allowing for a scalable and cost-effective way to manage multiple DER on a utility network.

Fourth Embodiment

[0083] The DERCOM network and system in the first embodiment using IEEE 1547-2018 approved communications protocols and IEEE 1547.1-2020 DER commands

Fifth Embodiment

[0084] The DERCOM network and system in the fourth embodiment enabling DER grid support applications in compliance with IEEE 1547-2018.

Typical DER Grid Support Applications

[0085] Intelligent Volt-Watt Control [0086] Reactive Power/Power Factor [0087] Low Voltage Ride Through [0088] Load and Generation Following [0089] Storage Systems Charge/Discharge Management [0090] Connect/Disconnect [0091] Dynamic reactive Current Injection (responding to change in voltage) [0092] Max Generation Limiting [0093] Intelligent Frequency-Watt Control [0094] Peak Limiting Function for Remote Points of Reference [0095] DER Protection—Island Detection and Grid Disconnects; Steady State Operation in Islanded Mode [0096] DER Load Balancing—Maintains L/G Ratio by Curtailing DER Output [0097] 3V0 protection—Avoids Backflow Through Transformer onto High Side [0098] ESS Charging Control—Controls Charging Parameters of Energy Storage [0099] ESS Frequency Regulation—Regulates Power Frequency [0100] Many Others

Sixth Embodiment

[0101] A closed-loop control software algorithm that monitors and manages station generation/load ratio in real time and uses the DERCOM network and system in the first embodiment (FIG. 5). The closed-loop control software is implemented in the D-DERM substation controller.

Seventh Embodiment

[0102] An embodiment of the algorithm in the sixth embodiment that uses a DERCOM network (FIG. 6).

[0103] Begin main control loop

[0104] For each station [0105] a. For each DER: Input to E-DERM the real time Generation (PGn: output power in Watts) and send reading to D-DERM [0106] b. Input to D-DERM, the real time power outflow from station (PS) [0107] c. Calculate in D-DERM the total Load (PS+PG1+PG2+ . . . ) [0108] d. Compare Generation to Load (G/L) ratio to factor K (typically: K=0.77) [0109] e. If G/L is greater than K, proceed to curtail DER output power by 10%; otherwise go to step a [0110] f. D-DERM send power curtailment command to DER via E-DERM [0111] g. Wait T seconds (default value: T=1) [0112] h. Send configuration information request command to curtailed DER [0113] i. Verify that DER changed its maximum output power limit to 90% of previous value; if DER didn't change its value, trip the DER [0114] j. Enter new limit in local D-DERM data base [0115] k. Wait L seconds (default value: L=5) [0116] l. Go to step a.
End control loop

Eighth Embodiment

[0117] The closed-loop control system in sixth embodiment used to avoid substation transformer backfeed into the utility transmission system and expanded to optimize circuit hosting capacity, eliminate the need for substation 3V0 protection, provide adaptive relay settings and enable other grid support applications.

Ninth Embodiment

[0118] The DERCOM network and system in the first embodiment, used for Front of The Meter (FTM) and Behind the Meter (BTM) applications. E-DERM devices connect to FTM or BTM sources and loads which can then be managed. Connection may be via wired, wireless, powerline or other means.

Tenth Embodiment

[0119] The DERCOM network and system in the first embodiment integrated with a GridEdge Distributed Generation Permissive (DGP) system (FIG. 4). Commands sent via DGP are highly cyber-secure. DGP communications may take a variety of forms: [0120] PLC for outgoing and external link for incoming [0121] PLC for outgoing only (one-way implementation) [0122] Two way over an external link with PLC supervision

Eleventh Embodiment

[0123] The DERCOM-DGP network and system in the tenth embodiment providing unintentional islanding protection, along with multiple DER grid support applications, thereby providing an all-in-one solution to grid optimization,

Typical DER Grid Support Applications

[0124] Intelligent Volt-Watt Control [0125] Reactive Power/Power Factor [0126] Low Voltage Ride Through [0127] Load and Generation Following [0128] Storage Systems Charge/Discharge Management [0129] Connect/Disconnect [0130] Dynamic reactive Current Injection (responding to change in voltage) [0131] Max Generation Limiting [0132] Intelligent Frequency-Watt Control [0133] Peak Limiting Function for Remote Points of Reference [0134] DER Protection—Island Detection and Grid Disconnects; Steady State Operation in Islanded Mode [0135] DER Load Balancing—Maintains L/G Ratio by Curtailing DER Output [0136] 3V0 protection—Avoids Backflow Through Transformer onto High Side [0137] ESS Charging Control—Controls Charging Parameters of Energy Storage [0138] ESS Frequency Regulation—Regulates Power Frequency [0139] Many Others
DER commands can be embedded within the UI permissive signal.

Twelfth Embodiment

[0140] The DERCOM-DGP network and system in the eleventh embodiment along with the closed-loop control software algorithm in the sixth embodiment (FIG. 5).

Thirteenth Embodiment

[0141] The DERCOM-DGP network and system in the eleventh embodiment along with the following control algorithm. This DERCOM-DGP system provides unintentional islanding protection and uses one-way powerline communications in lieu of a two-way external channel. While less accurate than a two-way communications implementation, it provides a conservative way to limit the G/L ratio, using nameplate generation data rather than actual real time generation.

[0142] For each DER on the station, the D-DERM shall: [0143] a. Store all DER nameplate information in D-DERM database [0144] b. Calculate approximate total station generation using sum of DER nameplate information [0145] c. Calculate approximate station load using sum of DER nameplate information and real time station outflow readings [0146] d. Calculate approximate station generation/load ratio (R) using results from b and c [0147] e. Compare R to allowable limit K [0148] f. Establish control link with DER [0149] i. Send a permissive signal when DER is allowed to export power [0150] ii. Stop the permissive signal when DER is not permitted to export power [0151] iii. Send a digitally encoded token to the E-DERM to enable sending a command to the DER [0152] g. If R>K, send a digitally encoded token to the E-DERM to curtail output power by 10% [0153] h. If station outflow does not immediately increase due to DER curtailment, D-DERM disconnects the DER from the grid by stopping the permissive signal [0154] i. Enter new curtailed generation value into nameplate data base (zero if DER tripped in step h), replacing previous value [0155] j. Go to b
The permissive commands are embedded within the DGP UI signal.

Fourteenth Embodiment

[0156] The network and system in the first embodiment through the thirteenth embodiment providing compliance with, and utilization of, the IEEE 1547-2018 and IEEE 1547.1-2020 standards.

Fifteenth Embodiment

[0157] The network and system in the first embodiment through the fourteenth embodiment used for monitoring and managing non-DER utility assets for other applications such as distribution automation and demand response.