BR-102025015377-A2 - SYSTEMS AND METHODS FOR MONITORING AND CONTROLLING ELECTRICAL NETWORKS

BR102025015377A2BR 102025015377 A2BR102025015377 A2BR 102025015377A2BR-102025015377-A2

Abstract

The present invention relates to an electrical network comprising a plurality of distribution transformers, a plurality of network protectors, each electrically connected to one of the distribution transformers, a secondary busbar electrically connected to each of the network protectors, and a control unit. The control unit is configured to receive data from each of the network protectors associated with the electricity flowing through them, analyze the data to determine if there is an electrical imbalance in any of the network protectors, and operate any unbalanced network protectors to disconnect the distribution transformers connected to the unbalanced network protector from the secondary busbar. The control unit is further configured to allow beneficial backflow through the distribution transformers, which can be created by generators coupled to the secondary busbar.

Inventors

David DeLeo
Franklin Miller

Assignees

RICHARDS MFG. CO. SALES, LLC

Dates

Publication Date: 20260310
Application Date: 20250724
Priority Date: 20240726

Claims (20)

1. An electrical network, characterized in that it comprises: one or more primary feeders configured to receive electricity from a primary substation; a plurality of distribution transformers electrically connected to one or more primary feeders, each of the plurality of distribution transformers being configured to receive electricity from one or more primary feeders and reduce the voltage of the electricity; a plurality of network protectors, each of the plurality of network protectors being electrically connected to a respective of the plurality of distribution transformers to receive electricity, each of the plurality of network protectors being configured to generate data associated with one or more electrical characteristics of the electricity flowing through them; a secondary busbar electrically connected to each of the plurality of network protectors, such that the plurality of distribution transformers are electrically connected to the secondary busbar via the plurality of network protectors; a control unit communicatively coupled to each of the plurality of network protectors, the control unit being configured to: receive data from each of the plurality of network protectors; analyze the data to monitor the electricity flowing through each of the plurality of network protectors; and in response to the determination that there is an electrical imbalance in one of the plurality of network protectors, operate the unbalanced network protector to disconnect the secondary busbar of the respective one of the plurality of distribution transformers to prevent backflow through the unbalanced network protector.
2. Electrical network, according to claim 1, characterized in that, in response to the determination from the data that there is no electrical imbalance, the control unit is further configured to allow beneficial backflow to flow through one or more of the plurality of network protectors.
3. Electrical network, according to claim 1, characterized in that the control unit includes a processing device, a memory device and a communication interface configured to (i) receive data from each of the plurality of network protectors and (ii) transmit one or more control signals to each of the plurality of network protectors to operate each of the plurality of network protectors.
4. Electrical network, according to claim 3, characterized in that the communication interface is configured to communicate with a plurality of network protectors via IEC-61850 protocol, DNP3 protocol or any other industry standard or customized protocol.
5. Electrical network, according to claim 3, characterized in that the control unit is communicatively coupled to a generator that is electrically connected to the secondary bus, the communication interface being further configured to monitor the operation and/or transmit one or more control signals to the generator to (i) pause the generator operation, (ii) cause the generator to be disconnected from the secondary bus, (iii) modify the generator output or (iv) some combination of (i), (ii) and (iii).
6. Electrical network, according to claim 1, characterized in that to analyze the data, the control unit is further configured to: determine, based on the data from each respective network protector, a value of at least one electrical characteristic associated with the electricity flowing through the respective network protector; and compare the value of at least one electrical characteristic for the entire plurality of network protectors to identify the unbalanced network protector.
7. An electrical network, according to claim 6, characterized in that the value of at least one electrical characteristic of one of the plurality of network protectors being different from an average value of at least one electrical characteristic in all of the plurality of network protectors by at least one limiting quality indicates that one of the plurality of network protectors is unbalanced.
8. An electrical network, according to claim 6, characterized in that the value of at least one electrical characteristic of one of the plurality of network protectors being different from a median value of at least one electrical characteristic in all the plurality of network protectors by at least a limiting amount indicates that one of the plurality of network protectors is unbalanced.
9. An electrical network, according to claim 6, characterized in that the value of at least one electrical characteristic of one of the plurality of network protectors being outside a predetermined acceptable range for at least one electrical characteristic indicates that one of the plurality of network protectors is unbalanced.
10. Electrical network, according to claim 6, characterized in that at least one electrical characteristic includes a voltage, a current, a phase angle, a quantity of electrical energy, harmonic measurement, rate of change of any of these parameters, or any combination thereof.
11. Electrical network, according to claim 1, characterized in that the control unit is a component separate from the plurality of network protectors.
12. Electrical network, according to claim 1, characterized in that the control unit is integrated with one of the plurality of network protectors.
13. Electrical network, according to claim 1, characterized in that the control unit is further configured to: identify, based on data analysis, a group of unbalanced network protectors from a plurality of network protectors where an electrical imbalance exists; identify, based on data analysis, a group of balanced network protectors from a plurality of network protectors where no energy imbalance exists; and operate the group of unbalanced network protectors to disconnect the secondary busbar of the respective distribution transformer electrically connected to each of the group of unbalanced network protectors.
14. Electrical network, according to claim 13, characterized in that the group of unbalanced network protectors contains a single one of the plurality of network protectors.
15. Electrical network, according to claim 13, characterized in that the group of unbalanced network protectors contains two or more of the plurality of network protectors.
16. Control unit, characterized in that it is for use in an electrical network that includes a plurality of network protectors, each electrically connected to a respective distribution transformer and all electrically connected to a secondary busbar, the control unit comprising: a communication interface configured to communicatively couple the control unit to each of the network protectors; a processing device; and a memory device that stores computer-readable instructions which, when executed by the processing device, cause the control unit to: receive data from each of the network protectors associated with the electricity flowing through each of the network protectors; analyze the data to monitor the electricity flowing through each of the network protectors; and, in response to the determination that there is an electrical imbalance in one of the unbalanced network protectors, operate the unbalanced network protector to disconnect the secondary busbar of the respective distribution transformer connected to the unbalanced network protector.
17. Control unit, according to claim 16, characterized in that the memory device also stores computer-readable instructions which, when executed by the processing device, cause the control unit to: identify, based on data analysis, a group of unbalanced network protectors from a plurality of network protectors where there is an electrical imbalance; identify, based on data analysis, a group of balanced network protectors from a plurality of network protectors where there is no power imbalance; and operate the group of unbalanced network protectors to disconnect the secondary busbar of the respective distribution transformer electrically connected to each of the group of unbalanced network protectors.
18. A method for operating an electrical network that includes a plurality of network protectors, each electrically connected to a respective distribution transformer and all electrically connected to a secondary busbar, characterized in that it comprises: receiving, in a control unit communicatively coupled to each of the network protectors, data associated with the electricity flowing through each of the network protectors; analyzing the data to monitor the electricity flowing through each of the network protectors; and, in response to the determination that there is an electrical imbalance in one of the unbalanced network protectors, sending a control signal, through the control unit, to the unbalanced network protector to disconnect the secondary busbar of the respective distribution transformer connected to the unbalanced network protector.
19. Method according to claim 18, characterized in that it further comprises: identifying, based on data analysis, a group of unbalanced network protectors from a plurality of network protectors where an electrical imbalance exists; identifying, based on data analysis, a group of balanced network protectors from a plurality of network protectors where no energy imbalance exists; and sending a first control signal, via the control unit, to the group of unbalanced network protectors to disconnect the secondary busbar of the respective distribution transformer electrically connected to each of the group of unbalanced network protectors.
20. Method according to claim 18, characterized in that the control unit is a separate component from the plurality of network protectors or in that the control unit is integrated with one of the plurality of network protectors.

Description

RELATED ORDERS [001] This application claims the benefit and priority of U.S. Provisional Patent Application No. 63/676,015, filed July 26, 2024, the description of which is incorporated herein by reference as if presented in its entirety. FIELD OF THE INVENTION [002] The present description refers, in general, to the monitoring and control of electrical networks and, more particularly, to the monitoring and control of electrical networks to allow backflow towards one or more primary feeders. BACKGROUND [003] Electrical networks use network protectors to prevent the backflow of electricity to distribution transformers and back to the substation due to faults in the electrical network or due to scheduled interruptions of the primary feeder. However, if the load supplied by the electrical network has its own electricity generation capacity (e.g., solar panels, etc.), the excess electricity cannot be sent to other electrical loads, as the network protectors prevent the backflow of excess electricity. [004] In recent years, there has been a significant expansion of distributed generation (DG) equipment to an increasing number of customer locations, some of which are served by underground secondary networks. Historically, secondary networks were designed as a "unidirectional" system, transferring power from the substation source, through medium-voltage grid feeders, transformers, and grid protectors, to the customer load. Conventionally, grid operators would not allow DG sites to be sized beyond the minimum customer load without using some alternative method to ensure that the net flow of power was always directed to the customer site. This may be less than ideal, as any excess generation capacity cannot be used to supply power to other customers. [005] One way to enable network protectors to operate bidirectionally, where power can flow to or from the customer location but ultimately still perform their primary function of isolating the network and feeder in response to both primary fault conditions and normal substation switching operations, is to set the allowed reverse power flow setting on the network protector relay to a much higher value than would be used for normal network operations. This will allow the protector to remain closed under a moderate reverse power flow condition and still trip in response to most faults. However, during a switching operation where the substation circuit breaker is manually opened (i.e., for maintenance rather than fault interruption), the protector would remain closed, causing the feeder to remain energized. To mitigate this, remote communications with the network protector can be used to establish a transfer tripping scheme where the opening of the feeder circuit breaker causes a tripping message to be sent to all network protectors on the affected feeder to trip and lock themselves, thus isolating the feeder from the secondary network. [006] Such a system has disadvantages, including the cost of implementing remote communication, the complexity of implementing data transfer in the utility's SCADA (Supervisory Control and Data Acquisition) system, and the reliability problems inherent in remote communications. Thus, there is a need for a system and method to autonomously monitor and control the backflow of electricity in an electrical network. SUMMARY OF THE INVENTION [007] According to some implementations of the present invention, an electrical network comprises: one or more primary feeders configured to receive electricity from a primary substation; a plurality of distribution transformers electrically connected to one or more primary feeders, each configured to receive electricity from one or more primary feeders and reduce the voltage of the electricity; a plurality of network protectors, each electrically connected to a respective distribution transformer to receive electricity, each configured to generate data associated with one or more electrical characteristics of the electricity flowing through them; a secondary busbar electrically connected to each of the plurality of network protectors, such that the plurality of distribution transformers are electrically connected to the secondary busbar through the plurality of network protectors; and a control unit communicatively coupled to each of the plurality of network protectors. The control unit is configured to receive data from each of the plurality of network protectors; Analyze the data to monitor the electricity flowing through each of the plurality of network protectors; and, in response to the determination of the existence of an electrical imbalance in one of the plurality of unbalanced network protectors, operate the unbalanced network protector to disconnect the secondary busbar of the respective distribution transformer connected to the unbalanced network protector. The control unit is further configured to determine, from the data, when there is no electrical imbalance and then allow beneficial backflow