AU2021211971A1 - Systems and methods for connecting electrical appliances to an electrical grid - Google Patents

Systems and methods for connecting electrical appliances to an electrical grid Download PDF

Info

Publication number
AU2021211971A1
AU2021211971A1 AU2021211971A AU2021211971A AU2021211971A1 AU 2021211971 A1 AU2021211971 A1 AU 2021211971A1 AU 2021211971 A AU2021211971 A AU 2021211971A AU 2021211971 A AU2021211971 A AU 2021211971A AU 2021211971 A1 AU2021211971 A1 AU 2021211971A1
Authority
AU
Australia
Prior art keywords
electricity
electrical
electrical grid
price
switch module
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
AU2021211971A
Inventor
Dean Holland CLIFT
Lee KERNICH
Gary Rosengarten
Cameron STANLEY
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rheem Australia Pty Ltd
Original Assignee
Rheem Australia Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rheem Australia Pty Ltd filed Critical Rheem Australia Pty Ltd
Priority to AU2021211971A priority Critical patent/AU2021211971A1/en
Publication of AU2021211971A1 publication Critical patent/AU2021211971A1/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/14—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B15/00—Systems controlled by a computer
    • G05B15/02—Systems controlled by a computer electric
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q50/00—Systems or methods specially adapted for specific business sectors, e.g. utilities or tourism
    • G06Q50/06—Electricity, gas or water supply
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00002—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by monitoring
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
    • H02J13/00034—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving an electric power substation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/007—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y02B70/3225—Demand response systems, e.g. load shedding, peak shaving
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems
    • Y04S20/222—Demand response systems, e.g. load shedding, peak shaving

Abstract

Disclosed is a system for connecting an electrical appliance to an electrical grid. The system comprises a switch module and a processing system. The switch module is configured to electrically connect the electrical appliance and the electrical grid. The processing system is configured to compare a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period, and, based on the comparison, operate the switch module to control the transfer of electricity between the electrical grid and the electrical appliance. The electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time. Also disclosed is a method for connecting an electrical appliance to an electrical grid. 3/3 FIGURE 3 Providing a switch module configured to electrically connect the electrical appliance and the electrical grid. (210) Comparing a current electricity price for the electrical grid to a statistical quantity representing electricity prices over a period for the electrical grid. (220) Based on the comparison, operating the switch module to control the transfer of electricity between the electrical grid and the electrical appliance. (230) 200

Description

3/3
FIGURE 3
Providing a switch module configured to electrically connect the electrical appliance and the electrical grid. (210)
Comparing a current electricity price for the electrical grid to a statistical quantity representing electricity prices over a period for the electrical grid. (220)
Based on the comparison, operating the switch module to control the transfer of electricity between the electrical grid and the electrical appliance. (230)
SYSTEMS AND METHODS FOR CONNECTING ELECTRICAL APPLIANCES TO AN ELECTRICAL GRID TECHNICAL FIELD
[1] The present invention relates to systems and methods for connecting electrical appliances to an electrical grid.
BACKGROUND
[2] Electrical grids should be balanced so that the amount of electricity supplied by a grid at any given time matches the demand for electricity from the grid at that time. Grid balancing is becoming increasingly challenging as electrical generation continues to decentralise and as highly variable, renewable energy sources, such as wind and solar energy, become more widespread.
[3] On the side of the consumer, certain electrical appliances may be configured to operate in ways that vary their load on the electrical grid, which may assist the process of grid balancing. For example, electric water heaters may heat water at fixed times only (usually during off-peak hours), or they may be provided with thermostatic control.
[4] However, these existing solutions do not adjust an electrical appliance's demand for electricity in a dynamic way based on to the amount of energy available from the electrical grid at any given time, so their ability to assist to balance the grid is limited.
[5] It is desired to address or ameliorate one or more disadvantages or limitations associated with the prior art, or to at least provide a useful alternative.
[6] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.
SUMMARY
[7] According to one example aspect, there is provided a system for connecting an electrical appliance to an electrical grid. The system comprises: a switch module configured to electrically connect the electrical appliance and the electrical grid; and a processing system. The processing system is configured to: compare a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period; and, based on the comparison, operate the switch module to control the transfer of electricity between the electrical grid and the electrical appliance. The electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time.
[8] In certain embodiments, the processing system is configured to operate the switch module to either allow or impede the transfer of electricity between the electrical grid and the electrical appliance. In certain embodiments, the processing system is configured to operate the switch module to increase or decrease the transfer of electricity between the electrical grid and the electrical appliance.
[9] In certain embodiments, the processing system is configured to compare the current electricity price to a quantity representing non-current electricity prices.
[10] In certain embodiments, if the current electricity price is less than the statistical quantity, the processing system is configured to operate the switch module to allow or increase a supply of electricity by the electrical grid to the electrical appliance for powering the electrical appliance. In certain embodiments, if the current electricity price is greater than the statistical quantity, the processing system is configured to operate the switch module to impede or reduce a supply of electricity by the electrical grid to the electrical appliance.
[11] In certain embodiments, the statistical quantity comprises a rolling average of electricity prices for the electrical grid over the period. In certain embodiments, the period excludes times in which the current electricity price applies. In certain embodiments, the period includes times in which the current electricity price applies. In certain embodiments, the period immediately precedes or immediately follows the time in which the current electricity price applies. In certain embodiments, the period does not immediately precede or immediately follow the time in which the current electricity price applies. In certain embodiments, the period is a 24-hour period.
[12] In certain embodiments, to compare the current electricity price to the statistical quantity, the processing system is configured to compare a difference between the current electricity price and the statistical quantity to an index threshold.
[13] In certain embodiments, to compare the current electricity price to the statistical quantity, the processing system is configured to: determine a price index based on the current electricity price and the statistical quantity; and compare the price index to an index threshold.
[14] In certain embodiments, the price index is:
x-x S-X
where a is the index, X is the current electricity price, and is a rolling average of the electricity prices over the period.
[15] In certain embodiments, the price index is:
X
where a is the index, X is the current electricity price, and is a rolling average of the electricity prices over the period.
[16] In certain embodiments, the index threshold is a static threshold. In certain embodiments, the index threshold is a dynamic threshold, and the processing system is configured to set the index threshold based on an urgency for the electrical appliance to receive and/or consume electricity from the electrical grid.
[17] In certain embodiments, the statistical quantity is determined from past electricity prices. In certain embodiments, the statistical quantity is determined from future electricity prices. In certain embodiments, the statistical quantity is further determined from the current electricity price.
[18] In certain embodiments, the electrical appliance is electrically connected to an auxiliary electrical source configured to supply electricity to the electrical appliance and to the electrical grid, and the processing system is further configured to alter an amount of electricity supplied by the auxiliary electrical source to the electrical grid by operating the electrical appliance to control its electrical energy consumption. In certain embodiments, if the current electricity price is lower than the statistical quantity, the processing system is configured to operate the electrical appliance to increase or allow electrical energy consumption by the electrical appliance. In certain embodiments, if the current electricity price is greater than the statistical quantity, the processing system is configured to operate the electrical appliance to reduce or stop electrical energy consumption by the electrical appliance. In certain embodiments, the processing system is further configured to: receive auxiliary supply data indicative of an amount of electricity supplied by the auxiliary electrical source to the electrical appliance; and operate the switch module to control an amount of electricity supplied by the electrical grid to the electrical appliance based on the auxiliary supply data.
[19] In certain embodiments, the electrical appliance comprises a water heater. In certain embodiments, the processing system is configured to operate the switch module based on: the comparison of the current electricity price to the statistical quantity; and an urgency for the water heater to heat water. In certain embodiments, the urgency depends on the temperature of water stored in the water heater, and the processing system is further configured to: receive temperature data indicative of the temperature of water stored in the water heater; and based on the temperature data, operate the switch module to control the transfer of electricity between the electrical grid and the water heater. In certain embodiments, the electrical appliance comprises an energy storage device.
[20] According to another example aspect, there is provided a method for connecting an electrical appliance to an electrical grid. The method comprises: providing a switch module configured to electrically connect the electrical appliance and the electrical grid; comparing a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period; and, based on the comparison, operating the switch module to control the transfer of electricity between the electrical grid and the electrical appliance. The electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time.
[21] According to another example aspect, there is provided a switch module for electrically connecting an electrical appliance to an electrical grid. The switch module comprises a processing system configured to: compare a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period; and, based on the comparison, operate the switch module to control the transfer of electricity between the electrical grid and the electrical appliance. The electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time. In certain embodiments, the switch module is integrally or separately formed with the electrical appliance.
[22] According to another example aspect, there is provided an electrical appliance comprising: a switch module configured to electrically connect the electrical appliance to an electrical grid; and a processing system. The processing system is configured to: compare a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period; and, based on the comparison, operate the switch module to control the transfer of electricity between the electrical grid and the electrical appliance. The electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time. In certain embodiments, the electrical appliance is a water heater.
[23] According to another example aspect, there is provided a system for connecting an electrical appliance to an electrical grid. The system comprises: a switch module configured to electrically connect the electrical appliance and the electrical grid; and a processing system. The processing system is configured to: compare a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period; and, based on the comparison, operate the switch module to control the transfer of electricity between the electrical grid and the electrical appliance.
[24] In certain embodiments, the electricity price at a given time is the retail price of electricity at the given time. In certain embodiments, the electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time.
BRIEF DESCRIPTION OF THE DRAWINGS
[25] Some embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which:
[26] Figure 1 shows an example system for connecting a water heater to an electrical grid;
[27] Figure 2 shows example data sources from which the processing system of Figure 1 may receive or obtain information; and
[28] Figure 3 is a flow chart of an example method for connecting an electrical appliance to an electrical grid.
DETAILED DESCRIPTION
[29] Embodiments of the invention provide a system for connecting an electrical appliance to an electrical grid, or for controlling the transfer of electricity between the electrical appliance and the electrical grid. The system comprises a switch module configured to electrically connect the electrical appliance and the electrical grid. The system further comprises a processing system configured to compare an electricity price for the electrical grid at a current time (i.e. a current electricity price) to a statistical quantity representing electricity prices for the electrical grid over a period. Based on the comparison, the processing system is configured to operate the switch module to control the transfer of electricity between the electrical grid and the water heater.
[30] Embodiments of the invention further provide a method for connecting an electrical appliance to an electrical grid, or for controlling the transfer of electricity between the electrical appliance and the electrical grid. The method comprises providing a switch module configured to electrically connect the electrical appliance and the electrical grid. The method further comprises comparing a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period. The method further comprises operating, based on the comparison, the switch module to control the transfer of electricity between the electrical grid and the water heater.
[31] In some examples, the electricity price at a given or particular time or period of time comprises the wholesale or dispatch price of electricity, which is the price set by an operator of the electrical grid to purchase from one or more electrical generators a sufficient quantity of electricity to meet an expected demand for electricity from the electrical grid at the given time or period. That is, the electricity price may be the price of electricity at or during the dispatch period, when electricity purchased from the electrical generators is dispatched to the electrical grid. In some examples, the electricity price at a particular time is the wholesale or dispatch price at that time. In some examples, the current electricity price is the spot-price or real-time price of electricity in the electricity market.
[32] In other examples, the electricity price at a particular time is the retail price of electricity at that time charged by an electricity retailer to an end user. That is, the price of electricity may be the price of supplying electricity to the electrical appliance at any given time. In some examples, the retail price comprises the wholesale or dispatch price and an additional amount or markup (e.g. a markup including profits and overhead costs) determined by the electricity retailer. In other examples, the retail price does not comprise, or excludes, the wholesale or dispatch price.
[33] In some examples, the statistical quantity represents non-current electricity prices, which may include past or historical electricity prices (i.e. electricity prices at one or more past times, preceding a current or present time) and/or future electricity prices (i.e. electricity prices at one or more future times, following a current or present time). In other examples, the statistical quantity represents non-current electricity prices (i.e. past and/or future prices) and the current electricity price. Therefore, the statistical quantity may be determined from past electricity prices, future electricity prices, and/or the current electricity price. The statistical quantity may be a mean or average, a rolling average, or any other quantity, measure, combination, or representation of two or more electricity prices at two or more times.
[34] The electrical appliance may be any device or system (e.g. a collection of devices) configured to use or consume electricity. In some examples, the electrical appliance is a device configure to use or consume electricity to store energy in any form, such as in the form of heat, chemical energy, electric charge, or any other form of energy. In some examples, the electrical appliance is an electric water heater configured to store water and to heat the stored water using electricity (i.e. an electric storage water heater). The water heater may also use electricity to perform other functions associated with its operation (e.g. measure temperature). In other examples, the electrical appliance is an energy storage device or an electrical storage device, such as an electric-vehicle battery or any other type of battery, configured to store energy and to convert the stored energy to electricity or an electric potential.
[35] The electrical grid may comprise any electricity distribution network, such as a public electricity distribution network, configured to distribute electrical energy that has been sold and bought on a market, such as a national electricity market, from generators to consumers.
[36] The wholesale or dispatch price of electricity is an indication of the balance of electrical supply and demand: it decreases when electricity supply exceeds demand, and it increases when electricity demand exceeds supply. For example, in a liberalised electricity market, the predicted load on an electrical grid is broadcast by the network provider in a period before dispatch, and electrical generators bid for the supply of electricity to meet the predicted load. Each generator may provide the network operator with a quantity of electricity it is willing to generate and with an ask price or offer price at which it is willing to sell the electricity generated. The predicted load is refined over time (e.g. a few days) as the dispatch period approaches, so that the generators' load schedules can also be refined and offer prices amended. At the dispatch period, the network operator selects, based on the quantity of electricity necessary to satisfy the full demand, one or more of the generators that have submitted the lowest offer prices, and sets the current electricity price to the highest price from among the selected generators' offers; electricity is then purchased from each of the selected generators at that price (e.g. if the electricity demand is 10 MWh, and Generator A bids 3 MWh at 10 c/kWh, Generator B bids 7 MWh at 12 c/kWh, and Generator C bids 7 MWh at 13 c/kWh, the electricity operator sets the spot price to 12 c/kWh, and purchases electricity for said amount from Generators A and B for the dispatch period). Since the demand for electricity is linked to the load on the electrical grid, the spot price at the dispatch period is a reliable indicator of the electrical balance conditions for the electrical grid.
[37] Therefore, by controlling an electrical appliance's connection to the electrical grid based on the real-time price of electricity, the load on the electrical grid may be adjusted in accordance with the state of balance of the electrical grid. In some examples, the electrical appliance is connected to the electrical grid if the current electricity price is reduced relative to non-current electricity prices (e.g. if the current price is lower than a quantity representing the non-current prices), which is indicative of a decrease in the demand or an increase in the supply of electricity. In some examples, the electrical appliance is disconnected from the electrical grid if the current electricity price is increased relative to non-current electricity prices (e.g. if the current price is higher than a quantity representing the non-current prices), which is indicative of an increase in the demand or a decrease in the supply of electricity. Therefore, the invention can balance or assist or contribute to the balancing of the electrical grid.
[38] In addition, the invention can assist in reducing the cost of electricity consumed by an electrical appliance, such as a water heater. Simulations using TRNSYS (Transient System Simulation Tool), a time-series simulation tool that tracks energy flow in a system and has been extensively developed for water heating applications, show the possibility of reducing the cost (at the wholesale spot price) of energy consumed. The simulation results show a cost reduction of 128 percent for a small consumer (1-person household) over a 1-year period, which accounts for payments to the consumer for consuming energy due to considerable negative spot prices utilised; a reduction of 89 percent for a medium consumer (2 to 3-person household); and a reduction of 59 percent for a large consumer (4 or more-person household). The reductions are relative to a current off-peak water heater, heating from 10 pm to 7 am. All simulations utilise data sets from South Australia in the calendar year 2018. Therefore, the invention may provide cost savings to end users of electricity.
[39] It will be appreciated that the term "processing system" may refer to any electronic processing device or system, or computing device or system, or combination thereof (e.g. computers, web servers, smart phones, laptops, microcontrollers, etc.), and may include a cloud computing system. The processing system may also be a distributed system. In general, processing/computing systems may include one or more processors (e.g. CPUs, GPUs), memory componentry, and an input/output interface connected by at least one bus. They may further include input/output devices (e.g. keyboard, displays, etc.). It will also be appreciated that processing/computing systems are typically configured to execute instructions and process data stored in memory (i.e. they are programmable via software to perform operations on data).
[40] Figure 1 illustrates an example system 100 for connecting a water heater 110 to an electrical grid 120.
[41] System 100 comprises a switch module 130 and a processing system 140. Switch module 130 and/or processing system 140 may form part of water heater 110 and may be contained in a casing of water heater 110 or they may be separate from water heater 110. Furthermore, switch module 130 and/or processing system 140 may be located either proximally to or remotely from water heater 110.
[42] Switch module 130 is configured to electrically connect or operatively couple to water heater 110 and electrical grid 120. Switch module 130 is further configured to control a transfer or flow of electricity between water heater 110 and electrical grid 120. To this end, switch module 130 may be configured to selectively connect (i.e. connect or disconnect) water heater 110 to electrical grid 120. Switch module 130 may comprise one or more switches, such as electrically operated switches (e.g. MOSFETs or any other transistor), mechanically operated switches, or any other kind of switch. In some examples, switch module 130 is a binary switch module, configured to either allow or impede the transfer of electricity between electrical grid 120 and water heater 110. That is, a binary switch module may simply connect or disconnect water heater 110 to electrical grid 120 without controlling an amount of electricity transferred between them. In other examples, switch module 130 is a modulating switch module, configured to control or modulate an amount of electricity transferred between electrical grid 120 and water heater 110.
[43] Processing system 140 is configured to compare a current electricity price for electrical grid 120 to a statistical quantity representing electricity prices over a period for electrical grid 120. Based on the comparison, processing system 140 is configured to operate or control switch module 130 to control the transfer of electricity between the electrical grid and water heater 110.
[44] The statistical quantity may be determined from past electricity prices and/or future electricity prices. In some examples, the current electricity price is also included in the determination or calculation of the statistical quantity. The future electricity prices may be predicted, forecast, or expected electricity prices, as determined by an operator of electrical grid 120 or by any other entity. In some examples, the future electricity prices are predicted based at least in part on the past electricity prices. In some examples, the future electricity prices are predicted based on factors such as a weather forecast, a day of the week, holidays, or any other factor that may influence future electricity prices.
[45] Processing system 140 may be configured to receive or obtain data of the electricity prices, for example, from the energy market operator or the network provider responsible for electrical grid 120. The current electricity price is updated at instants that may be minutes apart, such as every 5 minutes, or every 15 minutes, or any other length of time (e.g. hourly or daily). Processing system 140 may be configured to receive or obtain the current electricity price in real-time or within a time interval shorter than the time interval between price updates (i.e. before the current electricity price expires or becomes obsolete).
[46] In some examples, if the current electricity price indicates or represents a reduction in price relative to the non-current electricity prices, processing system 140 may be configured to operate or control switch module 130 to connect water heater 110 to electrical grid 120 and to allow or permit electricity from electrical grid 120 to be supplied to water heater 110 for heating water and/or for performing other tasks associated with the operation of water heater 110.
[47] Alternatively, if the current electricity price indicates or represents an increase in price relative to the non-current electricity prices, processing system 140 may be configured to operate or control switch module 130 to disconnect water heater 110 from electrical grid 120 and to impede or block electricity from electrical grid 120 being supplied to water heater
110 for heating water and/or for performing other tasks associated with the operation of water heater 110. Water heater 110 may then draw electricity from an alternative electrical source (e.g. a battery) to continue its operation or it may cease to consume electricity temporarily.
[48] In some examples, when switch module 130 is a modulating switch module (such as a switch module comprising transistors), processing system 140 is configured to operate switch module 130 to control an amount of electricity transferred, or a rate of transfer of electricity, between electrical grid 120 and water heater 110. In this way, the amount of electricity supplied to water heater 110 from electrical grid 120 may be varied in continuous or discrete steps. In some examples, the amount of electricity supplied to water heater 110 from electrical grid 120 is less than the amount required for water heater 110 to operate at its full heating capacity; in those cases, water heater 110 may draw any additional electricity required for its operation from an alternative electrical source other than electrical grid 120. The portion of electricity that water heater 110 may be allowed to draw from electrical grid 120 may depend on the comparison between the current electricity price and the statistical quantity.
[49] Electricity supplied from electrical grid 120 to water heater 110 may be consumed by water heater 110 as it is received (i.e. in real-time) or it may be stored in an electrical storage device (e.g. a battery) electrically connected to water heater 110 for consumption at a later time. Therefore, in some examples, switch module 130 is electrically connected to an electrical storage device of water heater 110 and/or to an electrical heating element of water heater 110.
[50] Processing system 140 may be configured to receive or determine one or more quantities or values representing electricity prices, such as one or more statistical quantities computed from the non-current and/or current electricity prices, that may then be compared to the current electricity price.
[51] For example, processing system 140 may be configured to determine or calculate a rolling statistical representation of electricity prices, such as a rolling average (also known as a moving or running average). The rolling average may be computed from non-current electricity prices in a period immediately preceding or immediately following a present time in which the current electricity price applies (i.e. past electricity prices consecutively prior or subsequent to the current electricity price). In some examples, the period used to compute the rolling average is a 24-hour period, which allows for consideration of a full diurnal cycle of electricity price changes. In other examples, the period used to compute the rolling average is greater than 24 hours, to reduce the impact of price fluctuations due to, for example, extreme events. However, it might not be beneficial to extend the rolling average beyond a certain time period; therefore, in some examples, the period used to compute the rolling average is less than five days. In other examples, the rolling average extends over any other time period, such as a time including or excluding the current time (i.e. the rolling average may include or exclude the current electricity price).
[52] To compare the current electricity price to the statistical quantity representing electricity prices, processing system 140 may be configured to receive or determine a price index based on the current electricity price and the non-current electricity prices (i.e. the price index is a function of the current electricity price and the non-current electricity prices), and to compare the price index to a predetermined amount or threshold. In some examples, the price index is or represents a difference between the current electricity price and statistical quantity representing the electricity prices. In some examples, the price index, a, is:
x-X a = _ (1) X
where X is the current electricity price, and 9 is a rolling average of electricity prices. For example, if X represents a 24-hour rolling average, a price index value of 0.8 indicates that the current electricity price is 20 percent of the average electricity price during the previous or following 24-hour period. For the price index of Equation 1, if the price index is less than or equal to 1, it becomes more preferable to consume electricity from electricity grid as the price index approaches 1.
[53] In other examples, the price index, a, is:
X a= - (2) X
where X is the current electricity price, and 9 is a rolling average of electricity prices. In other examples, the price index is any other function of the current electricity price and of the statistical quantity representing electricity prices.
[54] In some examples, the index threshold to which the price index is compared to determine how to operate switch module 130 is a static or fixed threshold (e.g. 0.8, for the index of Equation 1), which does not change automatically.
[55] In other examples, the index threshold is a dynamic threshold, which may be adjusted automatically with no human intervention. In some examples, processing system 140 is configured to set or adjust the index threshold based on the temperature of water stored in water heater 110 or, more generally, on an urgency for water heater 110 to heat water. The index threshold may be increased if the urgency to heat water decreases or if there is no urgency to heat water; alternatively, the index threshold may be decreased if the urgency to heat water increases. An "increase" in the index threshold generally means that a greater reduction in the current electricity price relative to the non-current electricity prices is required before switch module 130 is controlled to allow electricity to be supplied from electrical grid 120 to water heater 110. A "decrease" in the index threshold generally means that a smaller reduction (and, in some examples, even an increase) in the current electricity price relative to the non-current electricity prices is sufficient to operating switch module 130 to allow electricity to be supplied from electrical grid 120 to water heater 110.
[56] For example, the index threshold may be increased if water heater 110 is at full capacity or if the water stored therein is above a certain temperature. In such cases, when there is no or little need for water heater 110 to be connected to electrical grid 120, the index threshold may be increased so that a zero or even a negative current electricity price is required to allow water heater 110 to receive electricity from electrical grid 120. A dynamic threshold may therefore assist in balancing electrical grid 120 more effectively and in further reducing the cost of electricity consumed by water heater 110.
[57] A dynamic index threshold may be advantageous over a static index threshold when system 100 comprises multiple water heaters whose connection to electrical grid 120 is being controlled, as it may reduce the probability of multiple water heaters being reconnected to electrical grid 120 at the same time, potentially damaging the grid's infrastructure due to the sudden increase in load. Instead, by assigning to each water heater a separate dynamic index threshold that changes based on the individual water heater's urgency to heat water, the water heaters would, under normal conditions, be connected to electrical grid 120 at different times.
[58] In addition to being electrically connected to switch module 130, water heater 110 may be electrically connected or operatively coupled to an auxiliary or secondary electrical source or supply, which may be a local, on-site, or site-generated electrical source (i.e. an electrical source located proximally to, or at a same site as, water heater 110). The auxiliary electrical source may or may not be electrically connected to electrical grid 120. In some examples, the auxiliary electrical source comprises an electrical storage device, such as a battery, configured to store electrical energy for use by water heater 110. In some examples, the auxiliary electrical source comprises an electric generator, such as a photovoltaic module, configured to generate electrical energy.
[59] The auxiliary electrical source may be configured to supply electricity to water heater 110. The auxiliary electrical source may further be configured to supply (and/or sell) electricity to electrical grid 120, for example, through an inverter of the auxiliary electrical source. The supply of electricity stored in or generated by the auxiliary electrical source to electrical grid 120 may also assist in balancing electrical grid 120. In some examples, when the electricity price indicates that the load on electrical grid 120 has increased, or that the amount of electricity supplied to electrical grid 120 has decreased, processing system 140 is configured to control water heater 110 to reduce or stop (e.g. turn off) its energy consumption, thus allowing more electricity from the auxiliary electrical source to be supplied to electrical grid 120 and less to water heater 110. Alternatively, if the current electricity price indicates that the load on electrical grid 120 has decreased, or that the amount of electricity supplied to electrical grid 120 has increased, processing system 140 may be configured to control water heater 110 to increase or allow (e.g. turn on) its energy consumption, thus allowing less electricity from the auxiliary electrical source to be supplied to electrical grid 120, and more to water heater 110.
[60] In some examples, in addition to the comparison of the electricity prices, processing system 140 also takes into account an urgency, priority, or need for water heater 110 to heat water when operating or controlling switch module 130. The urgency to heat water may depend on, for example, the temperature of water stored in water heater 110, a time of day, the rate at which water stored in water heater 110 is being used, and/or any other factor. For example, water heater 110 may be configured to maintain the temperature of water stored therein above a minimum level, which may be determined by a need to ensure that a minimum amount of hot water is available and/or by a need to satisfy sanitation requirements, for example, to protect against the growth of Legionella.
[61] In some examples, the urgency to heat water is determined by water heater 110, which may be configured to alert or notify processing system 140 of the urgency so that processing system 140 can operate switch module 130 accordingly. In other examples, the urgency is determined by processing system 140, for example, based on data received or obtained from water heater 110. For example, processing system 140 may be configured to receive temperature data indicative of the temperature of water stored in water heater 110, and, based on the temperature data, operate switch module 130 to either allow or impede transfer of electricity between the electrical grid and the water heater.
[62] The urgency to heat water may be prioritised over the comparison of electricity prices. For example, when an urgency to heat water is determined to exist, processing system 140 may be configured to operate switch module 130 without taking into account the price comparison (i.e. switch module 130 is operated regardless of the current electricity price). In other examples, the urgency to heat water and the price comparison are both considered by processing system 140 to operate switch module 130. In deciding how switch module 130 is to be operated, the price comparison and the urgency may be given the same weight or different weights.
[63] Therefore, processing system 140 may receive or obtain different kinds of data or information to determine how to operate switch module 130. Figure 2 illustrates some example sources of information from which processing system 140 may receive or obtain data.
[64] One example source of information is one or more temperature sensors 112 of water heater 110. Each temperature sensor 112 is configured to measure the temperature of water stored in water heater 110.
[65] Another example source of information is an information system 150, which is configured to disclose or provide electricity price data for electrical grid 120, including the current electricity price. Information system 150 may comprise a public information system (e.g. a website or page on the World Wide Web) or any other information collection or distribution means. Information system 150 may be an information system of the energy market operator or the network provider responsible for electrical grid 120. For example, in Australia, the price for electricity on the National Electricity Market is published on the website of the Australian Energy Market Operator (AEMO). In some examples, data of past and/or future electricity prices is received or obtained similarly to the current electricity price. In some examples, data of past electricity prices is garnered, collected, or assembled by processing system 140 over time. For example, processing system 140 may store or classify the current electricity price as a past electricity price after an amount of time has lapsed and the price for electricity has been updated.
[66] Another example source of information is an electrical monitor or power sensor 160, which is configured to determine an amount of electricity supplied by an auxiliary or local electrical source 162 to water heater 110. Processing system 140 may be configured to receive local supply data from energy monitor 160 indicative of the amount of electricity supplied by electrical source 162 to water heater 110. Then, in examples in which switch module 130 is a modulating switch module, processing system 140 may be configured to operate switch module 130 to control an amount of electricity supplied by electrical grid 120 to water heater 110 based on the local supplied data. In this way, water heater 110 may be simultaneously supplied with electricity from electrical source 162 and electrical grid 120. The combination of the portions of electricity supplied by electrical source 162 and electrical grid 120 may correspond to the energy requirements of water heater 110, or it may not exceed a maximum power rating of water heater 110. For example, if local electrical source 162 produces 1 kW, and the maximum electrical consumption of water heater 110 is 3.6 kW, then switch module 130 may be controlled so that electrical grid 120 supplies no more than 2.6 kW.
[67] Processing system 110 may be connected to each source of information through a wired or wireless connection.
[68] Figure 3 illustrates a flow chart of an example method 200 for connecting an electrical appliance to an electrical grid.
[69] At step 210, method 200 comprises providing a switch module configured to electrically connect the electrical appliance and the electrical grid.
[70] At step 220, method 200 comprises comparing a current electricity price for the electrical grid to a statistical quantity representing electricity prices over a period for the electrical grid.
[71] At step 230, method 200 comprises operating, based on the comparison, the switch module to control the transfer of electricity between the electrical grid and the electrical appliance.
[72] Optional embodiments may also be said to broadly include the parts, elements, steps and/or features referred to or indicated herein, individually or in any combination of two or more of the parts, elements, steps and/or features, and where specific integers are mentioned which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.
[73] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims (34)

THE CLAIMS:
1. A system for connecting an electrical appliance to an electrical grid, the system comprising: a switch module configured to electrically connect the electrical appliance and the electrical grid; and a processing system configured to: compare a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period; and based on the comparison, operate the switch module to control the transfer of electricity between the electrical grid and the electrical appliance; wherein the electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time.
2. The system of claim 1, wherein the processing system is configured to operate the switch module to either allow or impede the transfer of electricity between the electrical grid and the electrical appliance.
3. The system of claim 1, wherein the processing system is configured to operate the switch module to increase or decrease the transfer of electricity between the electrical grid and the electrical appliance.
4. The system of any one of claims 1 to 3, wherein, if the current electricity price is less than the statistical quantity, the processing system is configured to operate the switch module to allow or increase a supply of electricity by the electrical grid to the electrical appliance for powering the electrical appliance.
5. The system of any one of claims I to 4, wherein, if the current electricity price is greater than the statistical quantity, the processing system is configured to operate the switch module to impede or reduce a supply of electricity by the electrical grid to the electrical appliance.
6. The system of any one of claims 1 to 5, wherein the statistical quantity comprises a rolling average of electricity prices for the electrical grid over the period.
7. The system of claim 6, wherein the period immediately precedes or immediately follows the time in which the current electricity price applies.
8. The system of claim 6, wherein the period does not immediately precede or immediately follow the time in which the current electricity price applies.
9. The system of any one of claims I to 8, wherein the period is a 24-hour period.
10. The system of any one of claims I to 9, wherein, to compare the current electricity price to the statistical quantity, the processing system is configured to compare a difference between the current electricity price and the statistical quantity to an index threshold.
11. The system of any one of claims I to 9, wherein, to compare the current electricity price to the statistical quantity, the processing system is configured to: determine a price index based on the current electricity price and the statistical quantity; and compare the price index to an index threshold.
12. The system of claim 11, wherein the price index is: x-X I-X
where a is the index, X is the current electricity price, and 9 is a rolling average of the electricity prices over the period.
13. The system of claim 11, wherein the price index is: X a= X where a is the index, X is the current electricity price, and 9 is a rolling average of the electricity prices over the period.
14. The system of any one of claims 10 to 13, wherein the index threshold is a static threshold.
15. The system of any one of claims 10 to 13, wherein the index threshold is a dynamic threshold, and wherein the processing system is configured to set the index threshold based on an urgency for the electrical appliance to consume electricity from the electrical grid.
16. The system of any one of claims 1 to 15, wherein the statistical quantity is determined from past electricity prices.
17. The system of any one of claims 1 to 16, wherein the statistical quantity is determined from future electricity prices.
18. The system of claim 16 or 17, wherein the statistical quantity is further determined from the current electricity price.
19. The system of any one of claims I to 18, wherein the electrical appliance is electrically connected to an auxiliary electrical source configured to supply electricity to the electrical appliance and to the electrical grid, and wherein the processing system is further configured to alter an amount of electricity supplied by the auxiliary electrical source to the electrical grid by operating the electrical appliance to control its electrical energy consumption.
20. The system of claim 19, wherein, if the current electricity price is lower than the statistical quantity, the processing system is configured to operate the electrical appliance to increase or allow electrical energy consumption by the electrical appliance.
21. The system of claim 19 or 20, wherein, if the current electricity price is greater than the statistical quantity, the processing system is configured to operate the electrical appliance to reduce or stop electrical energy consumption by the electrical appliance.
22. The system of any one of claims 19 to 21 when dependent on claim 3, wherein the processing system is further configured to: receive auxiliary supply data indicative of an amount of electricity supplied by the auxiliary electrical source to the electrical appliance; and operate the switch module to control an amount of electricity supplied by the electrical grid to the electrical appliance based on the auxiliary supply data.
23. The system of any one of claims 1 to 22, wherein the electrical appliance comprises a water heater.
24. The system of claim 23, wherein the processing system is configured to operate the switch module based on: the comparison of the current electricity price to the statistical quantity; and an urgency for the water heater to heat water.
25. The system of claim 24, wherein the urgency depends on the temperature of water stored in the water heater, and wherein the processing system is further configured to: receive temperature data indicative of the temperature of water stored in the water heater; and based on the temperature data, operate the switch module to control the transfer of electricity between the electrical grid and the water heater.
26. The system of any one of claims I to 22, wherein the electrical appliance comprises an energy storage device.
27. A method for connecting an electrical appliance to an electrical grid, the method comprising: providing a switch module configured to electrically connect the electrical appliance and the electrical grid; comparing a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period; and based on the comparison, operating the switch module to control the transfer of electricity between the electrical grid and the electrical appliance; wherein the electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time.
28. A switch module for electrically connecting an electrical appliance to an electrical grid, the switch module comprising a processing system configured to: compare a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period; and based on the comparison, operate the switch module to control the transfer of electricity between the electrical grid and the electrical appliance; wherein the electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time.
29. The switch module of claim 28, wherein the switch module is integrally or separately formed with the electrical appliance.
30. An electrical appliance comprising: a switch module configured to electrically connect the electrical appliance to an electrical grid; and a processing system configured to: compare a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period; and based on the comparison, operate the switch module to control the transfer of electricity between the electrical grid and the electrical appliance; wherein the electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time.
31. The electrical appliance of claim 30, wherein the electrical appliance is a water heater.
32. A system for connecting an electrical appliance to an electrical grid, the system comprising: a switch module configured to electrically connect the electrical appliance and the electrical grid; and a processing system configured to: compare a current electricity price for the electrical grid to a statistical quantity representing electricity prices for the electrical grid over a period; and based on the comparison, operate the switch module to control the transfer of electricity between the electrical grid and the electrical appliance.
33. The system of claim 32, wherein the electricity price at a given time is the retail price of electricity at the given time.
34. The system of claim 32 or 33, wherein the electricity price at a given time comprises the price set by an operator of the electrical grid to purchase from one or more electrical generators enough electricity to meet an expected demand for electricity from the electrical grid at the given time.
AU2021211971A 2021-08-02 2021-08-02 Systems and methods for connecting electrical appliances to an electrical grid Pending AU2021211971A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2021211971A AU2021211971A1 (en) 2021-08-02 2021-08-02 Systems and methods for connecting electrical appliances to an electrical grid

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AU2021211971A AU2021211971A1 (en) 2021-08-02 2021-08-02 Systems and methods for connecting electrical appliances to an electrical grid

Publications (1)

Publication Number Publication Date
AU2021211971A1 true AU2021211971A1 (en) 2023-02-16

Family

ID=85176232

Family Applications (1)

Application Number Title Priority Date Filing Date
AU2021211971A Pending AU2021211971A1 (en) 2021-08-02 2021-08-02 Systems and methods for connecting electrical appliances to an electrical grid

Country Status (1)

Country Link
AU (1) AU2021211971A1 (en)

Similar Documents

Publication Publication Date Title
US20230367348A1 (en) Method and apparatus for delivering power using external data
Jiang et al. Day-ahead stochastic economic dispatch of wind integrated power system considering demand response of residential hybrid energy system
US9489701B2 (en) Adaptive energy management system
CA2846342C (en) Use of demand response (dr) and distributed energy resources (der) to mitigate the impact of variable energy resources (ver) in power system operation
JP6592454B2 (en) Power control system, power control method and program
Lu et al. Residential demand response considering distributed PV consumption: A model based on China's PV policy
US20140200723A1 (en) System and Method for Energy Distribution
US20100114799A1 (en) Optimal dispatch of demand side electricity resources
Zhang et al. The performance of a grid-tied microgrid with hydrogen storage and a hydrogen fuel cell stack
WO2014143908A1 (en) System and method for energy distribution
JP6580159B2 (en) Water heater control system, control method and program
US11900488B2 (en) Energy control and storage system for controlling power based on a load shape
US20170270548A1 (en) Reducing Substation Demand Fluctuations Using Decoupled Price Schemes for Demand Response
Gomathy et al. Energy management system and peak shaving algorithm for smart home integrated with renewable energy
JP2020039222A (en) Power supply-demand control device, power supply-demand control system, and power supply-demand control method
Rahman et al. Modeling and performance evaluation of grid-interactive efficient buildings (GEB) in a microgrid environment
AU2021211971A1 (en) Systems and methods for connecting electrical appliances to an electrical grid
JP6479212B2 (en) Water heater control system, control method and program
Duan et al. Integrated scheduling of generation and demand shifting in day‐ahead electricity market
WO2023010154A1 (en) Systems and methods for connecting electrical appliances to an electrical grid
JP7354394B2 (en) Power management device and power management method
Ida et al. The Economics of the Smart Grid
Arun et al. Demand Response Frameworks for Smart Residential Buildings
Sarala et al. Grocery Store Flexibility Management Using Model Predictive Control With Neural Networks
Zhang et al. Operation of a Microgrid System with Distributed Energy Resources and Storage