Copper and other metal theft from electrical transmission and distribution networks. How to mitigate the security, safety and service risks by real time event alerting? Abstract The purpose of this paper is to discuss the detection and mitigation of security, safety impact and service continuity issues that result from metal infrastructure theft from electrical power delivery networks. Safety issues, both on substation sites and at the delivery points on the network are outlined, and the risks surrounding undetected theft explored. Mitigation of these risks requires timely detection and knowledge of the event. A current technology and methodology developed in collaboration with the power network operators that provides such detection capability is then outlined.
Introduction The worldwide metal theft pandemic has significant security, safety, service continuity and financial impact in many service environments. This impact on safety and service provision is particularly acute in the electrical transmission and distribution industry. While theft of valuable metals causes inconvenience and financial loss in most environments, we are regularly reminded of the consequential damage, power losses, fires, death and injury to both the public and power company employees associated with metal theft from electrical power delivery networks.
Metal infrastructure theft from electrical networks While metal theft targets vary from building materials, metal street furniture such as drain covers, through to widely deployed service sites, it is electrical service delivery infrastructure which is the most targeted and where the highest risks are realized. The principle areas of risk are:
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Personnel and public safety due to risk of injury or death due to electrocution, electrical fires or other related damage Service outage due to substation problems caused by immediate or cumulative stress to key infrastructure such as transformers and regulators Service outage due to delivery conductor, transformer earth cable or other such theft
These areas of risk for Electrical Distribution Network Operators largely derive from two principal theft events: • •
Substation grounding infrastructure theft, usually copper, from large and small sites Electrical delivery infrastructure theft, including delivery conductors and transformer earth cables
It is the exposed and necessarily disparate location of these sites and infrastructure that make them prime theft targets, as well as the perceived low risk of the theft for the perpetrator. To understand the risks associated with these events for the operator, the event itself needs to be understood. When assessing the costs of such a theft event, often only the cost of the materials and its replacement costs are taken into account. The safety and service outage risks and hence costs are variable but potentially far higher.
Substation grounding theft and its associated risks for the operator The attraction of substations for theft is well known; the presence of large quantities of high value copper used to ground infrastructure, which is seen as an easy, low risk target. While this is often the case, the grounding network is not always so benign, as is too often demonstrated through severe injury or worse. A typical substation theft usually starts with the easy to remove copper connections between the grounded grid under the substation and the equipment and supporting physical infrastructure above ground. Whether steel or reinforced concrete is used for physical support of bus bars, insulators and other site elements, the tapes or cables to the underground grid provide the grounding connection. Some thefts stop at the removal of much of these easy-to-harvest connections on a site. This renders large parts of the site ungrounded. While these are not expensive to replace, their removal renders the site unsafe. However, many theft events are more comprehensive and the perpetrators move on to more difficult to reach or more challenging infrastructure, which takes time to steal and can cause significant damage. Thieves are often very knowledgeable and know the areas of danger to avoid. Less informed perpetrators will try to harvest cable right up to insulators that support HV bus bars, often resulting in severe burns or fatalities. Another trend is that of removal of the grounding grid approximately 18 inches/450mm under the surface. After digging down to the grid, hooks are attached to the grounding grid, the other end of the cable attached to a vehicle, and as much of the material is hauled out of the ground as they can manage. While this has varying degrees of success in terms of material removed, it inevitably causes significant damage. To combat this activity, network operators have deployed many types of security solutions. Such solutions either aim to stop access to site (e.g. fences, locks), detect a perpetrator on site (e.g. movement sensors, cameras) or identify the perpetrator after the event (e.g. DNA dyes, cable etching). These solutions are applied on substation sites commensurate with the size and criticality of the site, with large core transmission sites often having comprehensive camera and movement sensor systems. Due to their numbers, security at small distribution sites is often limited to fences and locks. All these approaches are complementary and can be effective in their specific purpose, though the more sophisticated technologies can have limited deployment due to cost. Substations are physically complex environments and often provide a challenging environment for the more active of these solutions. While the majority of these solutions serve a specific and useful purpose in terms of security, they do not detect whether the most regularly recurring event has actually happened: removal of material from the grounding infrastructure. Since this event makes a substation inherently unsafe, detection is imperative. At larger substations where more security resources are deployed, removal of material presents a bigger challenge due to movement sensors and thermal cameras, though the more effective of these systems can only be deployed at large sites due to cost. Again, some perpetrators seem remarkably well informed and manage to harvest areas of the site where detection is less likely. As an example, a large transmission site that had a significant number of up-to-date cameras and other security resources had more than 35% of its grounding connections removed over a period of time prior to detection, which was through chance sighting of the damage by security staff (the grounding will take two years to reinstate). While the appropriate layers of security for a site can make the theft more difficult to carry out, organized groups continue to carry out damaging raids.
Safety and damage risk The primary concerns raised by copper grounding theft are the safety implications. An unsafe site is a danger to the network operator’s personnel, the public and customers at the power delivery points. There are regular reports of substation grounding theft causing power related damage and sometimes fires at customer sites, not just at the substation. The grounding infrastructure is designed to manage and dissipate faults, both minor and major, and high energy events such as lightning strikes to both lines and the substation itself. When all exposed metal work and equipment is grounded correctly and the grounding grid is in place as designed for that specific substation, touch potentials are at safe levels, fault routes operate correctly and have the capacity to manage extreme events. Grounding design and analysis is a complex science and removal of even a part of the grounding infrastructure can have unexpected results. Most operators have had multiple theft incidents of varying seriousness. A recent survey by the Electrical Safety Foundation International of over 600 electricity operators in the US confirmed that 95% of them had experienced copper theft events in a twelve month period. Those organizations also experienced 19 serious injuries and 13 deaths due to theft events. Unfortunately, a lot of substation engineers have been injured or worse over the years by walking onto sites that have had grounding removed. While there is now heightened awareness of this and walk round inspections prior to entry common, the more organized perpetrators are careful to steal where visual detection is less likely so that the maximum material can be harvested from a site over time. While visual inspection does detect the more obvious theft, monitoring of the grounded infrastructure itself is necessary to reduce the risk further. Whether the equipment whose grounding is compromised is a transformer, an automatic or manual switch or other typical site plant, the risks to personnel are clear.
The safety risk to the perpetrators is a less popular discussion, but a liability risk nonetheless, dependent on the country in which the crime is committed. In most countries it is accepted that the operator should do all it reasonably can to protect the criminals from themselves, though this can be difficult to achieve in reality. A fast response once the issue is detected is a significant step forward. While risk to personnel safety is well understood, there are many examples where theft at the substation has caused unstable or faulty power delivery. In some circumstances this can be dangerous for customers, due to high voltages and/or currents and the possible fires that result (e.g. domestic appliances). These occurrences are not common, but they present a real risk which requires swift action upon detection of the grounding theft from the substation. When they do occur, these events can be widespread and the damage and resulting compensation costly.
Service outage risks While the safety of people is primary, the potential for resultant damage to operational equipment on and off site is also of concern. Damage does not usually occur immediately upon removal of grounding from a transformer or switch. However, a voltage imbalance or other fault can stress equipment and cause a fault immediately or over a period of time. Equally, a high energy event such as a lightning strike can cause significant widespread damage if the substation equipment is not grounded. Avoiding service outage is a primary aim of all electrical power delivery companies. Pre-emptive action and preparation is central to achieving this. The resulting lost revenue, regulatory fines and in many cases, customer compensation, can quickly become a significant cost. The detection of substation theft events is an important capability that helps enable such losses to be avoided. Knowing that infrastructure has been removed and the networks capability to handle loads and faults compromised is the key. Some thefts result in immediate service outage, so detection of the event ‘as it happens’ is the ideal scenario.
Distribution infrastructure theft and its associated risks for the operator Theft of the delivery infrastructure at the periphery of the network is a growing trend. While each individual event does not have the potentially widespread impact of a substation theft, such events are rarely isolated and tend to be part of a concentrated activity within a geographic area. Such theft usually comprises of removal of pole transformer earth wires and the power delivery conductors from around 11kV down to three phase customer delivery voltages. While an individual pole transformer does not seem significant, its role as a mini substation site means that removal of its earth/ grounding reference has similar results as the same theft at a large substation. The resulting variances in voltage delivery to the customer(s) represents a potential danger and cost risk. Theft of such pole earth references is a common and growing trend due to the ease of access and low risk to the perpetrator. Removal is quick and easy and many can be harvested in a short period. While cost of material replacement is low, the manpower costs are proportionally high.
Theft of delivery conductors is less common but is a growing problem. Removal of the neutral conductor is usually followed by two of the three phase conductors. The third phase is often left in place to reduce the chance of the theft being detected (and the poles being dragged over). This theft by definition results in service outage so requires a fast response. Detection of this theft ‘as it happens’, is again required in order to deal with the issue in a timely manner. Dependent on the extent of the theft (as described), it will probably not be detected by currently deployed systems and resources. As stated, the risks to service delivery are evident. There are also danger risks to both the perpetrators and the public if the results of the theft leave live conductors in a dangerous state and position. Such thefts are usually very organized, resulting in significant lengths of conductors being removed. As for other metal theft, the cost of material replacement is not generally high. However, the operational costs of replacement can be very significant.
Mitigation of risks resulting from these events Central to being able to deal effectively and quickly with theft related risks is the accurate and timely knowledge of the events. Protection relay systems that are currently widely deployed within electrical networks do not notify the operator upon such theft, potentially leaving thefts undetected. It is these undetected thefts which represent the greatest safety and outage risks. Electrical network operators both in the USA and the UK have been researching the market for a possible solution for a number of years now. Security technologies have been the primary solution set that has been applied to try and reduce the incident rate. However, as stated, due to costs and suitability, many such technologies are only practical for implementation on larger transmission sites and even then, theft continues. For these reasons, the detection of such theft as it happens was identified as an industry requirement some time ago.
As a result, a collaboration project defined the need and specified a design brief for a solution approach to address this issue. The agreed design brief can be summarized as follows:
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Real time detection and notification of theft Must not introduce any signal onto the site Practical deployment methodology that does not disrupt service delivery Suitable for deployment on old and new sites alike Suitable for deployment on small and large substations Minimal false alarms Does not compromise current safety infrastructure or practice Cost effective asset: both capital and lifetime costs Difficult to circumvent
Working from this design brief, the system was funded by, and developed in collaboration with the energy industry, both in the UK and the USA. The resulting Cresatech CuTS®solution set is now being deployed in both markets.
The Cresatech CuTS®solution set comprises two systems that address the two principle theft events: substation grounding theft and delivery infrastructure theft. Cresatech CuTS®ZM has the task of detecting and alerting to grounding theft activity on small and large substations.
The primary purpose of the system is to notify the operator in real time theft and that the site’s safety has been compromised. The system detects removal of material by monitoring for slight but steady changes in the physical characteristics (inductance) of the sites grounded infrastructure. This technique is perfered for its environmental stability and for its minimal cabling required on the site for installation. Since substations have complex grounding infrastructures, the methodology breaks a substation into detection zones. This is required so that the slight changes that occur upon grounding removal do not get diluted beyond detectability through looking at too much infrastructure with one sensor.
Cresatech CuTS®LV has the task of detecting when either delivery conductors or pole transformer grounding cables have been removed. The primary purpose of the system is to alert in real time the operator to either customer service delivery interruption resulting from conductor theft, or the risk of unstable power delivery due to removal of pole transformer earth cable. The system is a miniature and low cost power analyzer that evaluates the electrical results of such theft and determines the likely cause.
Conclusion The ubiquitous security, safety and service continuity issues generated by metal theft have driven power network operator’s requirements for a cost effective method of detecting such theft activity as it happens. The Cresatech CuTS®ZM solution is suitable for wide network deployment at both large and small substation sites, since existing protection systems do not alert to theft unless virtually all grounding from site is removed, which is rarely the case. Cresatech CuTS® ZM sends a real time alert as the theft events occur so safety and service risks can be mitigated in the most suitable and effective manner. Occurrences of undetected theft from transmission sites through to pole transformers have been responsible for some of the worst safety scenarios for operators and public alike, and have been the cause some of the most high profile and damaging public service interruption events. Cresatech CuTS® provides a low cost real time alerting solution mitigating the security, safety and service continuity risks resulting from damage and theft from the power transmission network.
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