Wireless AMI Application and Security for Controlled Home Area ...

2unavailable when the home electric system is faulted or open.Wireless enables communication between AMI and the outlet,even with a fault in the electric connection between them.Comparatively, options like Ethernet cabling have extensiveinfrastructure costs with little flexibility to reconfigure thenetwork architecture.A wireless-based home area network for AMI (WHAN-SM)has more security challenges than possibly any other solutiondue to the shared wireless medium. There have been visionarydocuments on smart grids that call for improved security [6],[7]. There are researchers who have specifically focused onsecurity and AMI and called for more work to be done inensuring a secure framework, with some actually proposingsuch a framework or architecture [8] – [13] on which to buildsolutions. Based on a survey of the literature and discussionswith engineers and experts, what has been lacking, however, isa concrete, low-level approach that looks at various possibleattacks to such a WHAN-SM.This work takes a comprehensive look at wireless securityin WHAN-SM. Furthermore, countermeasures are developedfor both the utility and the customer. A key aspect thatdifferentiates security in WHAN-SM from that inconventional HANs is that there are two different entitieswhose interests must be kept secure: (i) the utility company,who must be sure that no one, including the customer, cantamper with the measurement and control of appliances asagreed upon, and (ii) the customer, whose privacy must beguarded at all times when the AMI is collecting and relayingdata, and that personal appliance management preferences arehonored at all times. The traditional wireless local areanetwork security protocols are based on a single partyapplication. Very limited work has been done for wirelesslocal area network security solutions under the presence ofmore than one stakeholder. This work pays special attention topossible attacks and countermeasures needed with theexistence of these multiple parties.The paper is organized as follows. In Section II, a moredetailed description is given of the WHAN-SM scenario.Section III looks at relevant security objectives in WHAN-SMand discusses possible attacks. In Section IV, solutions to theidentified attacks are proposed. Concluding remarks withsome directions for future work are made in Section VI.II. HOME AREA NETWORK FOR AMISThe AMI will enable energy meters installed in all customerpremises to communicate with the utility operated controlcenter and with appliances installed in the premises, and tocontrol the appliances’’ operation. The future AMI will havethe ability to control how many appliances could operate at agiven time and thus implement demand-side management forthe utility. In such an application the utility control centerlooks at aggregate loads from all its customers at a given timeand then issues specific control instructions to the AMIs. It isenvisioned that in the future when a customer participates inAMI, the AMI would have control over some specific class ofappliances (typically the high-load appliances that thecustomer can operate with some tolerance in delay). It isexpected that with introduction of AMIs, time of the daytariffs will become more popular, allowing customers tobenefit from having appliances operate at times of lower tariff.If control is done manually consumers are less attentive tovarying tariffs and thus less likely to optimize the energy costby using appliances at off-peak times [14]. Any infrastructurethat allows reduced human intervention in energy costoptimization is of high interest.A. Role of CommunicationAMIs are expected to introduce two new categories ofcommunication. The first, already employed by many utilitiesin the U.S., is between the energy meter and the utility controlcenter. This facilitates observation of real-time powerconsumption and any abnormalities in the system, and allowsdemand-side management. If real-time pricing in introduced,this category of communication will enable the consumer totrack the current price. In addition to the ANSI C12.22standard [15], significant work has been done on ensuringsecure communication between the meter and the utility [16],[17]. Many utilities in the U.S. have implemented AMI thathave the capability of this level of communication [18]-[20].If the AMI is to allow load and cost management, a secondcategory of communication between the meter and the users’appliances is also necessary. One of the major concerns ofimplementing this category of communication is the questionof consumer privacy [3], [21]. Customers have concerns aboutthe utility knowing what electrical appliances they are using atany given time. Therefore, a separate layer of communication,limited to the customer facility, is required. Using thiscommunication layer, the AMI will communicate with andcontrol the customer’s appliances without sharing thisinformation with any other stakeholders.It should be noted that if the second layer of control isachieved by enabling demand-side management, thengreenhouse gas emissions can be also controlled as well.Utilities subject to existing and proposed state and federalemissions regulations could benefit greatly.Further, the introduction of electric vehicles (EV) is aserious concern for utilities. EV charging will be stochastic innature and a large increased load on the distributiontransformers. Therefore, EVs require higher level bidirectionalhigher end communication; some of theinformation about EV charging should be communicated tothe utility (e.g. time required for charging, availability, andcharge level of the battery). Therefore EVs should becategorized separately when the communication architecture isdeveloped. As this scenario is still only emerging, we do notaddress this appliance class in this work. This work focuses onthe network within the home and how AMI deals withappliance classified in groups 1, 2, and 3, as described inFigure 1.B. Communication Requirements in a WHAN-SMIt may not be economical to have equal communicationcapability for all components; for example, a light bulb needsonly minimal communication infrastructure whereas an airconditioner needs to communicate more information.