NL1039384C2

NL1039384C2 - Flexible energy measurement and control system.

Info

Publication number: NL1039384C2
Application number: NL1039384A
Authority: NL
Inventors: Marnix Claudius Vlot
Original assignee: Uc Connect
Priority date: 2012-02-16
Filing date: 2012-02-16
Publication date: 2013-08-19

Description

Flexible Energy Measurement and Control System Field of the invention

The invention relates to a system for active control of energy being generated or consumed by 5 appliances connect to an energy supply network, specifically the method of measurement of energy flows to connected appliances, the related method to ensure appropriate accounting of different types of controlled and non controlled energy flows and methods for verifying correct reporting of accumulated energy flows by accumulated energy flow meters or appliances, localization in the energy network and registration of such appliances at a 10 registration entity and delegation of various network services to be performed in connection to the registered appliances to other networked entities.

Background of the invention

Energy distribution networks are increasingly managed in an active manner using information 15 and communication technology, so as to better and more efficiently match supply and demand on the energy distribution network and to take better account of transport limitations of the distribution network. This field is often referred to as “smartgrids”.

At present most end users of energy are kept unaware of the differences of the cost of the supply of energy over time: they pay a fixed rate per energy unit for energy usage. In order to 20 allow more active management of energy new smart appliances are conceived that use or generate energy at the end user’s premises in a flexible and controlled way with respect to the aforementioned energy flow management objectives. Since the most optimal way of consuming energy requires complex decision making at very frequent intervals it is useful to use a high degree of automation for controlling such smart appliances.

25 It is therefore interesting to provide an automated link of smart appliances to energy markets from which they draw or to which they supply energy through an energy distribution network. Taking into account the integral cost of demand or revenue of supply and cost and limitations of transport of energy, the need for and supply of energy over time and other cost, revenue factors or constraints, it is possible to come up with an optimized schedule for the energy flow 30 of such an appliance given the bounds of the application of the appliance.

Smart appliances are gradually introduced and the existing method of accounting for energy costs requires adaptation to supply fair compensation to the smart appliance owner, for instance reflecting energy market and network distribution value. However, most energy use and generation in a local energy network will typically occur in an uncontrolled manner with 1039384 2 respect to the momentary energy and network costs for the foreseeable future. Since the overall energy supply and network load is the sum of many of such small energy use or supplies, the overall network flows are more constant due to the statistical averaging effect of large numbers of uncontrolled demand by appliances. The energy industry today uses average 5 time usage profiles of customers that have no smart meter to allocate consumed energy to market time slots so as to come to a energy flow assignment per time slot for each supplier of energy.

When controlling smart appliances several options exist. Such appliances may be directly aware of momentary energy prices or may be controlled through an connected decision 10 system to the energy prices and other potential cost and revenue factors. The energy flow scheduling strategy that is most optimal may evolve over time as supply, demand, transport cost and other cost factor of energy change. A smart appliance and the control entity can offer an interface to the user via a device connected to the internet, to control settings and monitor the status and energy use, costs and the controllability benefits of the appliance and its control 15 entity. The implementation of the control and metering entity for an appliance can be done on servers on the internet, requiring no additional equipment at the user premises.

Summary of the invention

The invention improves on existing energy flow metering schemes by separating metering for 20 different types of flexibility of energy flow control so as to be able to suitably reward customers separately for the control flexibility of their appliances, specifically separating non-controlled (inflexible) flows from controlled (flexible) flows.

This invention further encompasses the establishment of such separate controlled energy flows by equipping so called smart appliances with their own energy flow metering facility.

25 Uncontrolled flows can then be derived by deducting the controlled flow from the overall energy flow by a central accumulated energy flow meter.

The invention provides the means to establish the controlled flow of one or a group of end customers as an energy flow that may be used by an operator as an account for provided benefits on energy markets or in other trades with or without the use of “smart meters” -30 energy flow meters that can record energy flows over time. By not requiring smart meters for measuring controlled energy flows smart appliances can be introduced more quickly and cost effectively in the market.

This invention further comprises a method whereby smart appliances, rather than precisely measuring their energy flows over time, may provide relatively course estimates that are 3 typically conservative, thus underestimating the flexibility of the device, and letting the central energy flow meter account for the remainder. Such simplified partially model based energy flow estimate can be much cheaper to implement and can be much more difficult to tamper with than using an energy flow meter in the appliance itself.

5 This invention further provides methods for registering appliances to preset entities on the network and arrange delegation of control, metering or other services to be performed in conjunction with the appliance to other network entities. This invention further provides a way to more easily identify the likely energy network that the appliance is connected to by using the local network address of the appliance or the address of the local network that the 10 appliance is connected to.

This invention further provides a method for establishing faulty or tampered with smart appliances by verifying the characteristics of use of each device against a set of rules, comparing it to other smart appliances with similar characteristics, comparing the reported energy flow to the control instructions provided to the smart appliance, verifying the identity 15 of the appliance using cryptographic technology or against registers of other registered appliances and known compromised identities.

Detailed description of certain embodiments

Fig. 1 represents an example of smart energy network deployment, in the form of a single 20 phase electricity network as is common in households. It schematically shows an external energy network connection 5 connected via a smart accumulated energy flow meter 1 to a local energy network 6, to which appliances 2,3 and 4 are connected. The accumulated energy flow meter 1 has an external communication connection 21 for transferring time based energy flow data to a metering entity 31. Furthermore the energy flow of appliance 3 can be 25 controlled via communication connection 20, smart meter 1 and communication connection 21 by entity 31, for instance as a result of local decisions made in energy flow meter 1, as a consequence of a combination of direct commands from the metering entity or as a combination of both. Note that a local control node for appliances may also exist as a device separate from the smart energy flow meter. Appliance 4 is directly controlled in terms of its 30 energy flow through communication connection 23 by control entity 33. The smart energy flow meter 1 can report the overall energy flow to the external network connection, and the metering entity may relay the collected data to an energy supplier that will use this for billing purposes. Through the control actions the aggregate flow of energy is more optimal and thus a lower energy bill or higher energy revenue can result for the end user.

4

Fig. 2 represents an example of an adapted network similar to that of Fig. 1 in which a separate energy subnetwork 9 has been connected to local energy network 6 via a separate energy flow meter 8 so as to separately measure the energy flow to the controlled devices to 5 controlled appliances 3 and 4. This separate energy flow meter 8 reports the controlled energy flow to subnetwork 9 to metering entity 32 through communication connection 22. This setup permits to measure the impact of the control of appliance 3 and 4 directly and thus permits alternative billing strategies for the power for appliance 3 and 4, e.g. using a variable tariff and continue charging those that are not controlled like appliance 2 on a fixed tariff, thus 10 enabling a well defined benefit assignment for the control actions. Examples of such variable tariffs may be day-ahead market prices (e.g. APX or EEX) or prices assigned to actions of balance and reserve power as often defined by System Operators on power networks. Assignment of the benefits of using such variable tariffs for suitably controlled appliances may be directly to the end user of energy or may be aggregated by an operator which 15 accumulates the controlled energy flow measurements so as provide the required account for a system operator or other market control entity for energy market accounting purposes, and which assigns benefits to end users for the ability to control their appliances in a less direct way. However, in both cases it is possible to assign the benefits of the flow control in a way that encourages end users not to inhibit the control of the flows through local overrides, i.e.

20 taking account of the level of control offered, the amount of energy flow that is controlled and the coincidence of controllability and need for control. At the same time the aggregation operator may use the separate measurements to account for his performance in meeting energy market obligations or performance.

25 Fig. 3 represents a modification of the network in Fig. 1 where appliance 3 and appliance 4 each have their own accumulated energy flow reporting facility connections 20 and 23 respectively for reporting their own energy flow over time. Appliance 4 reports the accumulated energy flow data to metering entity 32 via network connection 22. Appliance 3 reports its accumulated energy flow time data to metering entity 31 via network connection 30 24, central smart meter 1 and network connection 21. Network connection 24 is used to control appliance 2 similar as in Fig. 1. The embodiment of smart meters and subnetworks inside the appliances offers great simplicity in the deployment of new smart appliances since they are now fully self-contained in terms of their control and reporting of energy flows and no separate energy network as in Fig. 2 item 9 is needed and controlled appliances can be 5 connected directly to a existing local energy network 6. The controlled energy flows as reported through 22 and 23 can be deducted from the total energy flow measured by 1 and thus the uncontrolled energy flow resulting from appliance 2 can be established.

5 In case smart meters are not deployed typically energy operators responsible for such accounts are allotted a nominal flow at that time which represents an estimate of the average flow of a customer of the same type weighted by the total energy consumption over a longer period of the accounts to which he is responsible for. Operators can use the separate controlled energy account to establish their deviation from this nominal flow, e.g. by making 10 separate variable time tariff energy contracts for the controlled flow and accounting for the remainder of power flows under the nominal assignment. Alternatively they may just use only the deviations from the time average power demand of the smart appliances through control actions as a means to demonstrate regulation power to balance an electricity network or to provide other auxiliary power services, or ensure that by regulating energy demand they meet 15 their contract obligations on the power market with a much more precisely controlled timing.

Since controlled and uncontrolled energy flows are accounted for separately the smart appliances can be relatively coarse in reporting of their energy flows. By making a slightly conservative estimate of the controlled flow of an appliance the remainder will automatically 20 be accounted for under the uncontrolled flow account. Such a simplified account of energy use may be very easy to establish and require no explicit measurement functions in a smart appliance.

A smart appliance example is sketched in Fig. 4 in the form of a washing machine. The smart 25 washing machine 1 has a microcontroller 2 that controls the actions of the washing machine.

It can communicate via a wireless communication adapter 3 and antenna 4 to report to metering entities and receive control and/or information for decision making from control entities. The user has a limited user interface 25 with which he can select a program for washing and the flexibility permissible from a set of presets he has configured in 30 microcontroller 2 via the control entity and an internet connected user interface device. The smart washing machine is connected to the electricity outlet 6 via plug 5. Microcontroller 2 uses control connection 11 to operate switch 7 which controls the operation of water heating element 9, and uses control connection 12 to operate switch 8 and variable resistance 13 which jointly controls the operation and speed of motor 10.

6

The washing machine, controlled by a microcontroller may only report the duration of its water heating element being switched on as the control parameter, making a slightly conservative assumption on the power flow needed for the water heating element and not 5 including the power consumption of the motor. Such a very simplistic model can be implemented and verified in a very cost effective way. The simplified model for reporting controlled power consumption versus overall power consumption has been indicated in Fig. 5. With graph 1 representing the actual power consumption over time of a washing machine and graph 2 the reported energy consumption that is considered to be controlled. The remainder 10 of the power used by the washing machine is ultimately accounted for by the central energy meter.

It will be difficult to modify the washing machine so as to make it report power consumption when power is cheap on the washing machine tariff if the microcontroller in the washing 15 machine is difficult to modify or replace and the microcontroller can establishes it has switched on its water heating element (e.g. by feedback of the water temperature sensor).

This has been sketched in Fig 6, which is an extension of Fig. 4. Temperature sensor 14 is connected via connection 15 to the microcontroller 2, which uses the rising temperature of the water heated by water heating element 9 to detect if the power is actually used for heating 20 water and not been diverted for an alternate purpose. Furthermore the microcontroller in the washing machine can be equipped with a hidden cryptographic key that can be used by the metering entity to authenticate it. This will make it very difficult to replace the microcontroller with one that has alternate programming.

25 Any potential fraude, besides being fairly unrewarding for any typical appliance, would also almost certainly require the washing machine microcontroller program to be altered. To avoid such alterations tamper proof microcontrollers can be used which resist unauthorized modifications of the software stores in memories of the microcontroller, e.g. by verifying the authenticity of the software by the microcontroller itself or by mechanical protection of the 30 memories storing software, e.g. by integrating the software on the same chip as the microcontroller or taking other mechanical measures. Last of all the microcontroller may contain a hidden cryptographic key, e.g. complementing a certificate, that can be used by an external entity to establish its authenticity, thus avoiding the complete replacement of a microcontroller by an unauthorized version.

7

When first connected to the communication network appliances should register themselves with a registration entity so as to be associated with the energy account of the local energy network they are connected to and to permit the user to set its control strategy. Typically there is no direct locality association between the energy network and the communication network 5 used to communicate with an appliance. The user may therefore have to manually identify an appliance with the registration service, e.g. through an identity printed on a label on the appliance. This is a relatively cumbersome operation. In a typical internet connection setup as indicated in figure 10 appliance 1 and appliance 2 are connected via a local network connection to network router 3 that contains a Network Address Translation (NAT) function 10 10, translating local internet addresses used in messages on the local network to its own internet address. It uses “ports” defined in the internet protocol to associate messages from the outside which all use the same internet address, namely that of the router, as destination to route back to the originating devices connected to the network. Entry 13 in the NAT indicates that appliance 1 is communicating to entity 4 on the network over port 13. Message 21 from 15 entity 1 is translated as coming from the IP address of router 3 in the NAT function 10 by entry 11, and sent on as message 22 with modified source address and port to entity 4. Entity 4 can send back a message 23 to the router with port 10. The router uses the network address translation function 10 entry 11 to locate the destination on the local network as appliance 1 and forwards the message with as message 24 to appliance 1. Entity 4 is now aware of the 20 address of the router that is used by the local appliances to communicate ver the internet. In case appliance 2 is connected for the first time to the local network it can attempt to communicate to entity 4 through network router 2 with message 31. Network router 2 makes a new NAT entry 12, modifies the source address to its own, and changes the port number to 12, and forwards the massage 32 to entity 4. Entity 4 can now associate the new appliance 2 25 to the same energy account as appliance 1 since they are using the same network address. Some caution may be necessary since there may not be a direct correspondence of energy accounts to local area network router addresses on the internet.

An similar method of associating appliances to energy accounts that can be used through the 30 location in the communication network is indicated in figure 11. Appliance 1 is connected via local area network 5 to network modem 2. Network modem 2 is connected via a unique line 6 to the network exchange 3. Network exchange 3 has a register of telecommunication account identities to the lines in table 10, and a specific entry 11 to identify line 6 to its internet provider account. Entity 4 an identify the messages it receives from appliance 1 through 8 assistance of the network exchange, e.g. by using the IP source address of the message, and it can request the exchange for the identity of the internet provider account with line 6 through message 7 on which exchange 10 can then return the account identity in message 8.

5 In general it is useful that controlling entities can verify the identity of a smart energy appliances and verify the integrity of the microcontroller. For this purpose the microcontroller may have a hidden cryptographic key that is never directly exposed to the world. However, the microcontroller can use die cryptographic key in operations on data and the result of such operations may be revealed to the outside world. The unique value of this cryptographic key 10 may be verified without it being exposed to the outside world, thereby verifying the identity of the microcontroller: see A.J. Menezes, P.C. van Oorschot and S.A. van Stone, “Handbook of Applied Cryptography”. By properly hiding the cryptographic key in the microcontroller it is not possible to change the microcontroller in the smart energy appliance since it would not be able to perform the same cryptographic operations as the original since it does not have the 15 same hidden cryptographic key. Figure 9 provides a further example of the identity check by entity 1 connected via a network to appliance 2. The physical communication network itself has not been represented in figure 9, only the messages that flow over it. In this example appliance 2 sends a message containing its cryptographic certificate 10 containing its public key 11 to entity 1. Entity 1 can use the data in certificate 10 to identify the appliance 2, which 20 typically involves verification of the integrity of the certificate data using a cryptographic signature of the issuing entity of the certificate. The entity then can use public key 11 to perform an encryption operation 21 on randomly generated data 13 to create a so called challenge to the appliance. The challenge is sent to the appliance which uses its secret cryptographic key 12 to decrypt the challenge and send back the result, or a summary of the 25 result to the entity 2. Entity 1 verifies the result or the summary thereof by comparing it to the original data 13 or the summary thereof. If the result matches the entity can conclude that the microcontroller of the appliance has the secret cryptographic key matching to its identity data in the certificate.

30 The identify of appliances may be communicated in the form of cryptographic certificates: packets of data signed with the private key of a certificate authority that can be verified as unique using the public key of that same certificate authority: see A.J. Menezes, P.C. van Oorschot and S.A. van Stone, “Handbook of Applied Cryptography”. This technique can be applied to the verification of identity as reported by appliances: i.e. it will not be possible to 9 synthesize such identity data by parties that do not have access to the private key of the certificate authority. Therefore the only option to “impose” as a genuine appliance may be to use a copied certificate. The certificate may contain the public key of a public-private key pair known in asymmetrical cryptography, which then can be used to verify that the 5 microcontroller in the appliance indeed has access to the unique hidden private key, thus proving the appliance’s identity data is matched to it’s hidden unique key.

Further verification of the potential duplication of the identity data and possible of the hidden key may be performed by a registration entity by verifying the identity data of the appliance 10 with databases of registered entities. Also a database may be created that contains known compromised identities so as permit a registration entity to quickly identify appliances using such compromised identities.

The typical power use characteristics of an appliance can be monitored to detect potential 15 fraude or malfunctioning of the appliance. E.g. excessively long heating times of a washing machine, higher than typical power use, very high frequency use like starting and stopping of the heating element within the time of a washing cycle, and other abnormalities in power flow metering reports can all be automatically detected by the metering entity and made available for suggestions of inspection.

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In order to deal with lapses in communication connection and in the metering entity the appliance can keep a limited account of its energy use over time. Since this account can be based on the specific power flow characteristics of the appliance it can be stored quite efficiently in the appliance, e.g. by storing the times the main load was switched on and off 25 and assuming a constant energy flow when switched on. In case communication cannot be established for a longer period the buffer may overflow. This will simply result in lost controlled energy flow reports and increase in uncontrolled energy flow. Since it is very unlikely that control can be effected but at the same time measurements cannot be retrieved from an appliance, a limited buffer should be sufficient.

Further integrity checks can be performed on the identity data reported by an appliance by comparing it to other registered appliances. The entity may use a central data base or other distributed data base techniques to perform such a verification. Such a check can also be used 30 10 to identify a previous registration of the same appliance, and request the owner of that registration to confirm the appliance has been transferred to a new registration account.

In order to make quick checks it is possible to create a databases of known stolen identity data 5 of appliances, that may be used to create illegal equipment. The entity that registers a new appliance can verify the identity data against such a database and inform the end user or smart energy system operations personnel of such an event.

It should be noted that reporting of energy consumption by appliances may have a different 10 format than that of a typical smart meter. It may e.g. reflect only the times an appliance or a large energy flow affecting component of it was switched on and off, allowing the metering entity to use this information and a known nominal power consumption for the appliance to compute the actual power consumption over time.

15 Smart appliances may have a very basic user interface which is not adequate to make more sophisticated settings, like preferred times a washing machine should finish and when it should not run. Similarly it may not be able to provide sophisticated feedback like a graph of its accumulated power consumption over time and the economic gain achieved by using smart grid control over it’s operation. Since the control and metering is all performed by computers 20 on a network these can offer such settings control and information through a web interface on a PC, smartphone or similar devices that can offer sophisticated user interfaces.

A smart appliance can register itself with a default registration service so that it can be assigned to the end user’s energy account and so that it can be linked to a control entity.

25 Through a user interface device linked through the internet or another communication network the user may use the default registration service to assign energy flow accounting and energy control to another entity in a convenient way, e.g. to a local control box in the home or the control service of a local network operator. Fig. 7 provides an example of the registration process. Entity 4 can act as a control and measurement entity and it has been preregistered by 30 the user via message exchange 10 to default registration service 2 to be the control and measurement entity for his smart appliances. When a new appliance 1 is connected for the first time it will register itself with a message exchange 11 to a default registration entity 2. The default registration entity 2 will contact user interface device 3 to request the user to complete the registration with message exchange 12, which the user completes resulting in 11 message exchange 13, indicating he assigns the control and measurement entity for appliance 1 to be entity 4. Default registration entity 2 then notifies entity 4 of the new appliance 1 with message exchange 14. Entity 4 then can send a message 21 to the registration entity 2 which can perform some minor processing and send it along as message 22 to appliance 1.

5 Conversely appliance 1 can send a message 23 to registration entity 2 which can perform some minor processing on it and forward it as message 24 to entity 4.

In other cases it may be useful to manage initial registration of appliances through the default registration service, but to hand off actual control over the appliance completely to another 10 entity. Fig. 8 is a variant of Fig. 7, whereby through message exchange 15 the default registration entity send the identity of entity 4 to appliance 1 so that appliance 1 can register with entity 4 for measurement and control services with message exchange 16. Entity 4 can now send a control message 31 directly to appliance 1 and appliance 1 can send energy measurement data messages directly to entity 4.

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Claims

A method for determining the energy flow control contribution of a group of devices whose energy flow can be controlled remotely with regard to the exchange of energy between an external energy network and a local energy network connected via a central energy flow balance meter, wherein on the local energy network a further group of devices is connected whose energy flow cannot be controlled remotely and the group of remotely controllable devices is connected to a local energy subnetwork which is connected to the local energy network via a local energy flow meter and where the energy flow control contribution of the group of controllable devices becomes 10 determined by sending measured values from the local energy flow balance meter over a connected communication network to an external energy flow balance collecting entity.

A method according to claim 1, wherein the group of devices whose energy flow 15 can be controlled remotely with regard to the exchange of energy between an external energy network and a local energy network consists of a single device wherein the local energy flow balance meter of this single group devices is part of that device and where there is no longer a separate local subnetwork for this single group. 20

A method according to claim 1, wherein one or more groups of devices whose energy flow can be controlled remotely are connected to the local energy network via a respective own local energy flow meter and a respective own energy subnetwork and wherein the energy flow balance which is not by the local energy flow balance 25 meters of the subnetworks recorded in a time interval is determined as the difference of the central energy flow balance meter and the sum of local energy flow balance meters in that same time interval.

4. A device with remotely controllable energy exchange with an energy network, a control unit in the device with a communication network connection for communicating with an external energy flow balance collecting entity, the device comprising various energy flow processing components which the control unit can switch on and off separately or control in intensity and wherein the manner in which the energy flow balance in the device is generated for a time interval is determined by multiplying the sum of the 1039384 different parts of the time in which each part of the device has functioned in that time interval by an energy flow time value per part and the intensity .

An apparatus according to claim 4, wherein the control unit of the apparatus is provided with measuring provisions that can determine energy flows or the effect of processing energy flows through one or more components of the apparatus, and wherein the control unit of the apparatus checks whether energy flow processing of a part or a number of parts actually takes place by means of these measuring facilities and when exceeding predetermined limits this communicates with the energy flow balance collecting entity.

A method for detecting possibly erroneous reporting of the energy flow balance by a group of remote-controlled devices according to claim 1 or 15 of an apparatus according to claim 4 by comparing the reported energy flow balance for a time interval with a time interval for the group devices or minimum or maximum values known for the device for this time interval.

7. A method of detecting possibly erroneous reporting of the energy flow balance of a group of remotely controllable devices according to claim 1 or of an device according to claim 4 by determining peaks or troughs in the reported energy flow balance in the time and the duration between compare these peaks or troughs with a minimum or maximum value known for the group of devices or for the device. 25

A method for detecting possibly erroneous reporting of the energy flow balance of groups of remote-controlled devices according to claim 1, wherein each group of energy-generating devices is connected to the local network via its own local network and own local energy flow balance meter and wherein the sum of The reported energy flow balances of all local energy flow balance meters in that time interval are subtracted from the energy flow balance of the central energy flow balance meter in that time interval and a possible error is determined if the difference is less than zero.

A method for detecting the integrity of the control unit of a device according to claim 2 or claim 4 by an entity on the network connected to the device wherein the control unit of the device contains a hidden cryptographic key and the entity and the control unit execute a challenge-response protocol in the device that allows the entity to verify the identity of the hidden cryptographic key without being able to derive it from messages sent over the network.

10. A method for detecting the integrity of the control unit of a device according to claim 2 or claim 4, by an entity on the network connected to the device wherein the control entity compares identity data and this identity data with the identity of devices known to be known is that their identity may have been copied or with the identity of other registered devices.

A method of delegating network service provision for a device according to claim 2 or claim 4 by a registration entity to an entity, wherein the entity is connected to a registration entity, the device initially connecting with the registration entity, and after which the entity and the device exchange messages through the registration entity to realize the services for the device.

A method of connecting a device according to claim 2 or claim 4 to an entity providing services to the device, wherein the identity of the entity is known to the registration entity, the device first The entity connects to a registration entity, after which the registration entity sends the device a message with the identity of the entity so that the entity can send messages to the device or the registration entity sends the device a message with the identity of the entity so that the device can send the entity messages.

A method of locating the central energy flow balance of the network via which the device is connected to the external energy network according to claim 2 or claim 4 by communicating the device's network communication address or the network address of the network through which the local network is connected the device is connected to an external communication network by comparing the network address with devices already registered or by having them identified by the communication network unit that provides the connection to the local network as belonging to a specific communication connection. 1039384