A high-altitude nuclear weapon carried by a single SCUD type missile and detonated only 30-80 miles in height can produce an electromagnetic pulse (EMP) that would directly impact a region of 500-800 miles in radius disrupting and meaningfully damaging the electrical power generation, transmission and distribution system with the simultaneous destruction of much of the communications and electronic equipment and infrastructure that drives the economy. In other words, EMP attacks the very interconnectedness that supports and enables the economy to function at a level consistent with our current quality of life.

Depending on the specific characteristics of the EMP attacks, unprecedented cascading failures of major infrastructures could result. In that event, a regional or national recovery would be long and difficult, and would seriously degrade the safety and overall viability of our country. The primary avenues for catastrophic damage to the country are through our electric power infrastructure and thence into our telecommunications, energy, transportation, and other infrastructures. These, in turn, can seriously impact other important aspects of our country's life, including the financial system; means of getting food, water, and medical care to the citizenry; trade and production of goods and services.

Later in October 1962, the Soviet Union performed a series of three high-altitude nuclear tests over what is now Kazakhstan in which they exploded 300-kiloton weapons at approximately 300, 150, and 60 kilometers above their test site. In these tests many more impacts were noted in electrical systems including physical damage to power line insulators, outages of long communications lines (both buried and above-ground), damage to diesel power systems, and impacts on radar systems. Clearly the fact that the Soviet tests were performed over land provided a greater opportunity for electrical systems to be exposed. Russian scientists indicated that in nearly all situations, the observed system impacts were due to the interaction of the HEMP fields with long metallic lines (on the order of 100 meters or longer), which then conducted disabling transient voltages and currents into the affected systems. Later work by Russian scientists examining the specific outages of two communication lines provided a clear indication that these specific outages were due to the late-time HEMP, which lasts for tens of seconds after the detonation. Russian scientists reported that on each shot they observed damage to overhead and underground buried cables out to distances of 600 kilometers. They also observed surge arrestor burnout, spark-gap breakdown, blown fuses, and power supply breakdowns.

During the U.S. "STARFISH" nuclear test at an altitude of about 400 kilometers above Johnston Island,, some electrical systems in the Hawaiian Islands, 1400 kilometers distant, were affected, causing the failure of street lighting systems, tripping of circuit breakers, triggering burglar alarms, and permanent damage to a commercial telecommunications relay facility that caused it to cease functioning.

The recovery of any one of the key national infrastructures is dependent upon the recovery of others. The longer the outage, the more problematic and uncertain the recovery will be. It is possible for the functional outages to become mutually reinforcing until at some point the degradation of infrastructure could have irreversible effects on the country’s ability to support its population.

Equipment connected to conductive wires such as power or phone lines (even water lines) are especially vulnerable since the long lines effectively serve as huge receiving antennae. For that reason, EMP can also disrupt or even damage basic electrical distribution equipment. Long electrical transmission lines are highly susceptible to attracting and conveying the electrical energy released by EMP. Not only are longer lines more likely to receive the EMP, the energy collected can increase along the length of the lines (according to some estimates to as much as 3,000,000 volts). Consequently, EMP is likely to cause short circuits and damage major components of the electrical power transmission and distribution system.

The damage that can be inflicted by an EMP on such objects may vary for a number of reasons, depending on how the objects accepts or couples‘ the energy, how large the item is, how delicate it is and what secondary effects may be produced within the system once it is disrupted or damaged. For example, SCADA (system control and data acquisition) devices that are connected to larger power systems can be disrupted or damaged causing management and safety measures to be defeated. This can result in larger system failures and damage. In general, the surge of electrical power through a circuit as a result of an EMP could disrupt or damage most electronic devices, especially those with modern low-voltage integrated circuits.

Electromagnetic Pulse (EMP) is an intense energy field that can instantly overload or disrupt numerous electrical circuits at a distance. Modern high technology microcircuits are especially sensitive to power surges. Older electrical components are generally built more massively, and are more tolerant of electromagnetic pulse. However, as modern electronics shrink in size, circuitry is becoming increasingly vulnerable to electromagnetic interference. Therefore, countries with infrastructure that relies on older technology may be less vulnerable to the disabling effects of HEMP or HPM than countries that rely on a higher level of technology.


The key vulnerable electronic systems are SCADA along with digital control systems (DCS) and programmable logic controllers (PLC). SCADAs are used for data acquisition and control over large and geographically distributed infrastructure systems while DCSs and PLCs are used in localized applications. These systems all share similar electronic
components, generally representative of components that form the internal physical architectures of portable computers. The different acronyms by which we presently identify SCADA, DCS, and PLC should not obscure the fact that the electronics have evolved to the point where the differing taxonomies are more representative of the functional differences of the electronics equipment rather than differences in the electronics hardware itself.  Electronic control equipment and innovative use of electronic controllers in equipment that is not usually considered control equipment are rapidly replacing the purely electromechanical systems and devices that were their predecessors. The use of such control equipment is growing worldwide, and existing users are upgrading equipment as new functionalities develop. The U.S. power industry alone is investing about $1.4 billion annually in new SCADA equipment. This is perhaps 50 times the reinvestment rate in transformers for transmission. The present rate represents upgrade and replacement of the protection and control systems to ever more sophisticated microelectronics at roughly 25 to 30 percent annually, with each new component more susceptible to EMP than its predecessor. The shift to greater electronic controls, computers, and the Internet also results in fewer operators and different operator training. Thus the ability to operate the system in the absence of such electronics and computer-driven actions is fast disappearing. This is almost certain to have a highly deleterious effect on restoring service in the event of an EMP attack.

Damage to SCADA equipment is assumed to be highly correlated with damage to either the electrical grid or communications systems. Damage to electronic equipment is assumed to be highly correlated with damage to the electrical grid. Similarly, damage to large and small elements of the electrical grid or communications systems is also assumed to be highly correlated. Damage to control items within a major power network may result in damage of its own. As a result, damage to the electrical grid or to communications systems is assumed to subsume damage to SCADA equipment and to electronic equipment. On the other hand, damage to the electrical grid and to communications systems is assumed to be both independent and interdependent. Both systems will suffer direct EMP damage that is not necessarily a function of the damage rendered upon the other. However, damage to the electrical grid will degrade the ability of communications networks to function while damage to communications systems will degrade the ability of electric utilities to restore their systems. As a result of these assumptions, the cumulative effect of an EMP on critical infrastructure is assumed to be largely determined by impacts on the electrical grid and communications systems. Cumulative damage is then determined by multiplying the remaining capacity of the electrical grid by the remaining capacity of communication systems.

Relay protection

Electro-mechanical relays are the old-fashioned devices that contain no integrated circuits but function using high-power relays. They are still used in about 20-50 percent of applications, but that share is continuing to decline. As expected, these are immune to EMP upset up to the highest levels tested. Renouncement electromechanical, enabling computer control instead of direct human intervention and use of broad networks like the Internet, results in ever greater reliance on microelectronics and thus the present and sharply growing vulnerability of the power system to EMP attack. Just as the computer networks have opened the possibility to cyber assault on the power system or to electrical power system collapse associated with software failure (as during the August 14, 2003, blackout), they have provided an opportunistic pathway for EMP attack that is likely to be far more widespread, devastating, and difficult to assess and restore. Switches, relays, and even generator exciters now have microprocessors and analog-to-digital converters. These and other low-power electronics cannot be expected to withstand EMP-generated stresses unless they are well protected. Protection must encompass both device design and system integration. Even a well-designed system installed without regard for EMP intrusion via connecting lines can be rendered inoperative by EMP stress. There is a serious question regarding whether manual control of the system sufficient to allow continued service will be possible even at a much-reduced state in the aftermath of EMP.
The main channels of destructive force impact on the following electronic equipment: power lines of all voltage classes, control cables and wire communication lines, air. Since digital protective relays (DPR) is connected to external power lines, branched network of control cables and wires, power line antenna-cables (by VT and CT) and computer network, the destructive effect on them can be both very high and at the same time hidden.

The reticence of electromagnetic attack is increased by the fact that the analysis of damage in the destroyed equipment does not allow identifying the cause of damage, since the same damage can be a result of either intentional (attack) or unintentional (e.g., lightning induction) destructive forces. This circumstance allows an attacker to use this technique repeatedly with success.

High-frequency sources of high-power emission, operating in the centimeter and millimeter range, have an additional mechanism for the penetration of energy into equipment through so-called "back doors", i.e., even through small holes, openings, windows and cracks in metal housings and through poorly shielded interfaces. Any hole that leads inside the equipment acts as a crack in the microwave cavity, allowing microwave emission to form an extensional standing wave inside the equipment. The components located at opposite assemblies of the standing wave will be exposed to strong electromagnetic fields and overvoltage. Memory elements and modern highly-integrated microprocessors are especially sensitive to this kind of impacts.

Thus, it is clear that it is not that easy to protect ourselves from all these "troubles". And even such well-known noise-resistant technology, like optical fiber, is prone (it may seem strange) to the impact of powerful electromagnetic pulses. First, optical fiber lines are equipped with microelectronic-based and even microprocessor-based terminals (Optical Multiplexer FOCUS, for example) designed to convert electric signals into light and vice versa. Second, it is known that light polarization vector in optical fiber can be changed under external magnetic field (strictly speaking, this is a basic principle for magneto-optical current transformers available in the market today). Due to this, the signals of relay protection systems and communications transmitted by optical fiber, built in a power line wire (a very common technology today) will be subjected to distortions under high pulse currents flowing through the same wires and creating pulsed magnetic fields. This is far from being a theoretic survey only. Today there are faults of such systems registered during the lightning current in power lines.

Two multiplexers BroadGate BG-20 planed today to be connected in addition betwen two OM FOCUS to transfer signals between relay protection.

Universal fully integrated multiplexers BroadGate BG-20

These are very complex microprocessor-based device intended not for transfer signals between relay protection only, but for connection of all kinds of equipment (including telephone, cellular, radio) on substation via Ethernet and Internet protocols.   

Other modern equipment, for example BB FOCUS, offered by AMETEK company, based on Ethernet protocol and wiring network in addition to optical connection also.

BB FOCUS will transport channel information for almost every type of equipment installed in substation, including:

- Video surveillance
- Substation LANs
- Protective Relays (directional comparison, current differential, direct transfer trip, etc.)
- Private automatic branch exchange (PBX) voice network
- Synchronous/asynchronous data
- Telephone systems

This is
very dangerous tendency in our opinion: to integrate the relay protection equipment together with many other kinds of equipment via Ethernet\Internet. Unfortunately, the historical negatives for using Ethernet in critical communication applications, such as protective relaying, have been overcome with today technology.

Certainly there is no way to protect such high-sensitive electronic equipment of modern power stations and substations from natural and, particularly, intentional electromagnetic effects completely. 


Smart Grid

The oldest electromechanical elements were very well insulated and required sustained signals to operate. This is the contrast to microprocessors base equipments. They are more sensitive to overvoltages and overcurrents in control cables.

It is truly remarkable how well our power systems have been improved by electronics to provide for much greater efficiency and safety. SCADA, as well as digital control systems and programmable logic controllers, have enhanced the operation and automation of power systems allowing for remote operation and the effective operation of very complex networks. This can be viewed as both a blessing and a curse, the latter due to the increased vulnerability of the network to EMP and other forms of electromagnetic interference.

Two new factors are now playing a role in this complexity: the advent of the "smart grid" and the growing need for cyber security. Both are drawing the attention of grid security personnel, perhaps to the detriment of attention needed to develop better protection from EMP. The security component of the smart grid program is mainly oriented to protection from cyber crime as the expanded communication system needed for a smart grid opens up more opportunities for cyber attacks.

While electronics and microelectronics are omnipresent in today's grid environment, the "smart grid" will greatly increase their numbers. It will maximize the use of integrated circuits to manage every step from the generator to the consumer. If they are the first victims in a major EMP event, all of that investment would be for naught.
The core of smart-grid technology — computer-controlled circuits, relays and sensors — would be vulnerable sitting ducks for EMPs. 

In particular the concept of the “smart grid” is under active consideration, and while the precise details of such a plan are not clear, it is clear that a major objective is to collect more data on the grid and to provide that data to the operators of the grid. The problem with many proposals for the smart grid is that there will be a proliferation of millions of computers (smart meters), which will be placed at homes and businesses to monitor the use of power in real time. These data will allow the system operators to operate their grids more efficiently and to eliminate the need for extra margins. These distributed computers will be vulnerable to the threat of radiated and conducted high frequency threats (such as E1 HEMP) and will be impacted by severe harmonics created during E3 HEMP and geomagnetic storms.

For the operation of the electric power grid, the HEMP E1 and E3 pulses are the most important. Research performed for the EMP Commission clearly indicates the following concerns:

1) Malfunctions and damage to solid-state relays in electric substations (E1)
2) Malfunctions and damage to computer controls in power generation facilities,
substations, and control centers (E1)
3) Malfunctions and damage to power system communications (E1)
4) Flashover and damage to distribution class insulators (E1)
5) Voltage collapse of the power grid due to transformer saturation (E3)
6) Damage to HV and EHV transformers due to internal heating (E3)

There’s been plenty of evidence recently that the Smart Grid could become a serious security risk for IT and households

Other problems

All life support systems (power system, water supply, telecommunications, communication, etc.) would all be put out of operation within a few moments. For this purpose there are special IEC standards, which detail the methodology for testing the steadiness of electric network equipment to high-altitude electromagnetic pulse (HEMP). Special mobile simulators generating pulses similar to those that are induced in power lines wires under HEMP were designed for such testing. According to data cited in this document, the overvoltage in dead power lines under HEMP becomes so high that it causes a breakdown of even the linear insulators of 35 kV class and, naturally, of all lower class insulators. If the same pulse penetrates the live power line, even 110 kV insulators are broken-down.

Illustration from the international standard IEC/TR 61000-1-3 representing test of 35 kV and 110 kV power line with simulator HEMP.


It is obvious that the use of special technologies to protect sensitive electronic equipment will lead to additional price increase of relay protection and SCADA. But this is the price that one has to pay for machinery progress.

But if we do not do it today, we can find ourselves in a situation, when it will be late to do it, since the dependence of our life on electronics, computers and microprocessors has become so high that carelessness in the field of protection of these systems from intentional influence of direct electromagnetic emission is comparable with crime and can lead to unpredictable consequences. It is noteworthy that several years ago the mass media were reluctant to publish articles on this topic, being afraid to attract attention of terrorists and criminals. However, after the last extensive damage in the US power, system terrorists have paid attention to the dependence of modern Western civilization on power industry themselves in a range of their statements and threats. Afterwards, there was a considerable number of articles devoted to the issue of exposure of society’s life support systems to electromagnetic terrorism in the New York Times and other mass media. For example, it is obviously shown that power systems are the main target of terrorists attack.

Hence, the carelessness of power systems management and workers, who have shut their eyes to this problem for many years, is somewhat appalling. It is nothing short of criminal carelessness to neglect the huge amount of publications on this topic in special technical journals, mass media, Internet and even books.

The author was shocked that not only ordinary power energy specialists, but also managers do not have even minimal knowledge on this topic. Moreover, the author’s attempts to raise this topic in articles and on relay protection forums lead to mockery and “pooh-poohing” towards him.

The power industry’s actual tendency to broaden implementation of microprocessor-based devices of relay protection, which control power equipment on the one hand and the tendency to increase the number of elements in microchips (which is accompanied by the decrease of their steadiness to external electromagnetic impacts) – on the other hand, form a rather dangerous vector in the background of progress in the field of creation of distant destructive impact devices. And the “ostrich” policy of unwillingness to know and to understand future dangers has never had any good consequences …

about EMP in YOUTUBE