The SolidGround™ neutral blocker is the most effective and economical solution to protect the electric power grid from stray DC, Solar Storms (GMD) and Nuclear EMP E3.

SolidGround™ protecting a 300 MVA 345kV / 138kV Transformer - Automatically triggered into Blocking Mode more than 30 times since installation, successfully blocking GIC and preventing Harmonics from Solar Storms.

Simple Circuit - 3 parallel paths to ground ensuring the transformer is grounded 100% of the time

SolidGround™ can operate as an Active Device (automatically switches into Blocking Mode only when neededor a Passive Device (continually in Blocking Mode) giving utilities strategic options on how to best protect their power grid.

Tested and Proven Technology

SolidGround™ is currently operating on the U.S. power grid and performing as designed.  

American Transmission Company Presentation on the Continuing Operational Performance of SolidGround™ on the power grid (MIPSYCON, November 2017)

Click image above to read ATC Presentation on SolidGround™

Click image above to read ATC Presentation on SolidGround™

2018 Janney Report recommends SolidGround™:

Click image above to see report

Click image above to see report

  • "Given most utilities are likely to reduce rates to customers due to recent lowering of corporate federal tax rate from 35% to 21%, perhaps tax savings could be redeployed into...resiliency investments."

  • "...focus initially on protecting the largest, most important transformers..."

  • "High Voltage transformers comprise 3% of the total...but they carry 60-70% of the country's electricity."

  • "...the entire 5,000 [HV transformers] could be outfitted with state-of-the-art, field tested and proven technology such as SolidGround™ GIC/EMP neutral blockers..."

  • " would seem a logical course of action to protect this most critical of grid equipment..."

U.S. Department of Defense unclassified EMP E3 field strength of 85 V/km

SolidGround™ Protects the Power Grid from both Nuclear EMP E3 and Solar Storms:

Protecting the grid against Solar Storm induced quasi-DC current (GIC) provides the foundation for protecting against the higher anticipated quasi-DC currents induced by EMP E3.  SolidGround™ (Standard model) can initially be installed to protect against Solar Storms and later upgraded in the field at any time to protect against very high EMP E3 fields (>35 kV DC) - there is no wasted effort.

2017 EMP Report to the Commission

"EMP E3...induces currents of 100's - 1000's of amperes in long conducting lines (a few kilometers or greater) that damage components of the electric power grid itself as well as connected systems." (p. 3)

"We have empirical evidence that EMP and solar storms damage transformers within the electric grid..." (p. 8)

"Installation of blocking devices in the neutral to ground connections of transformers will significantly reduce the probability of damage from solar storms and... EMP E3." (p. 8) [bold emphasis added]

Important to install Neutral Blocking Devices (to protect against GMD and EMP E3) before installing EMP protection for the E1 Pulse - must block DC from entering our grid before installing E1 filters:

“… when we do these [DC] injection tests – the harmonics… were about 50% higher with the EMP [E1] filter in the circuit than without that filter in the circuit…What we have is a filter designed to protect against one challenge [E1 Pulse] that exacerbates the problems due to geomagnetic disturbances.” - Idaho National Laboratory Results, Scott McBride, Dupont Summit: Mitigating High Impact Threats to Critical Infrastructure, December 6, 2013

solidground™ emp Model:

EMP.Alert™ - Patented E1 Trigger System

EMP.Alert™ - Patented E1 Trigger System

  • SolidGround™ electronics are shielded and filtered against the effects of E1, E2 and IEMI.

  • Modular capacitor bank add-ons provide blocking protection against very high currents (>35 kV DC withstand) induced by the Nuclear EMP E3 pulse.

  • The EMP.Alert™ Trigger System detects frequencies (specifically in the EMP E1 range) in nanoseconds and triggers SolidGround™ into "blocking mode" within 250 milliseconds of the E1 pulse (1 - 2 seconds before the E3 induced DC currents arrive).

  • Or, if preferred by the utility, SolidGround™ can operate as a Passive Device using "Passive Mode" which places capacitors in the neutral continually during normal operation, automatically bypassing the capacitors only for very short periods when necessary such as during a fault.

SolidGround™ has been Validated

Click SolidGround™ Brochure above to Download

Click SolidGround™ Brochure above to Download

  • SolidGround™ was extensively studied and modeled by the University of Manitoba.

  • Fully fault tested at KEMA High Current and Voltage Laboratories in Pennsylvania proving the robustness of design.

  • SolidGround™ was the subject of a NERC sponsored study performed by the Electric Power Research Institute (EPRI) in 2014 which concluded that neutral blocking devices have no unintended consequences when introduced into a power grid network.

  • EMP E3 tested on a live grid at Idaho National Labs by the U.S. Department of Defense (DoD) and the U.S. Defense Threat Reduction Agency (DTRA) and met all performance requirements.

  • No system resonance has been reported, relays operated correctly without requiring changes.

SolidGround™ has a perfect record, successfully operating on the power grid for many years

Benefits of SolidGround™

Protects the most critical, costly and long lead items of a Power Grid: High Voltage (HV) / Extra High Voltage (EHV) Transformers, Converter Transformers (HVDC), Generators and Circuit Breakers against the effects of Nuclear EMP E3 and all levels of Solar Storms.

Blocks GIC (DC) from Invading the AC Power Grid

  • Immediate Benefit: SolidGround™ Blocks GIC and Prevents the generation of Harmonics which continually invade the power grid at the high voltage level and build as they travel into the lower voltage distribution network towards load, causing billions in economic loss to customers in the U.S. each year due to common low-level solar storms.

  • SolidGround™ prevents the degradation of transformer insulation, voltage spikes across core and the increase in dissolved combustible gases in transformer oil due to moderate level solar storms

  • Enhances the robustness of aging transformers, stops existing cumulative GIC stress

  • SolidGround™ is designed to work on nearly all HV, EHV and Converter Transformers (HVDC). It can be used to protect an old existing transformer and then reused on a new replacement transformer.

Enhances the Stability and Reliability of the grid:

  • Prevents transformer half-cycle saturation due to GIC or EMP E3 induced currents

  • Prevents the generation of harmonics

  • Reduces VAR consumption

  • Prevents voltage collapse due to severe GIC

  • Reduces or eliminates the added cost of replacement VARs - cost of power generation and transmission by eliminating the need for "Uneconomic Dispatch" (utility sales, purchases and power transfer adjustments) during solar storm (GMD) events.

  • Simplifies or eliminates the need for expensive and complex utility response procedures to solar storm events which may not be effective. SolidGround™ is always ready to provide automatic and immediate protection at the precise time and location where needed.

  • Reduces or eliminates transformer vibration, noise

  • Reduces misoperation of relays and protective equipment due to harmonics

  • Standard GMD model protects up to 8 kV DC. EMP upgrade protects against higher anticipated E3 fields (>35 kV DC).

Features Overview

Multiple, redundant, parallel, individually fused capacitors, all systems fault protected

Robust Design and highly Fail Safe

  • SolidGround™ provides a hard wired metallic ground path and an effective AC ground through capacitors

  • Major components are proven, industry standard, the highest quality, provided by ABB and Schweitzer

  • Components are designed to take multiple faults with no cool down period required

  • Fully automatic with no operator action required

  • Scalable to protect the entire grid against a severe Carrington-level geomagnetic disturbance (GMD) and Nuclear EMP E3.

Controls built by Schweitzer Engineering Laboratories (SEL)

Schweitzer Control Electronics

  • Continuously monitors for GIC currents, GIC induced harmonics and EMP E1 as desired giving complete visibility into what is happening on the Power Grid.

  • Settable thresholds allow for site-specific customization

  • Communicates with SCADA Systems

  • Allows for alarms, warnings, messages to other systems or sites and logging of GIC activity

  • Allows manual control of unit for specific purposes such as testing, if desired.

  • Shielding protection can be provided for EMP E1 and IEMI as desired.

DuraGap™ enclosure installed on SolidGround™

DuraGap™ Overvoltage Protection

  • Robust patented spark gap specifically designed because there was nothing available in the market capable of handling the unique combination of voltage and amperage required by utilities.

  • Simple, Passive Device/EMP proof (no triggering electronics), Dual redundant.

  • In KEMA Lab tests DuraGap™ easily carried 20 faults (8 cycles) with 10 kV breakdown and 56 kA peak (20 kA RMS). Breakdown voltage did not increase due to the patented gap preserving design.

  • Overvoltage protection for repeated high fault (56/20 kA) currents. No cool down period required.

56/20 kA rating can be increased as needed by order.

EMP E3 Pulse

The threat and consequences of a Nuclear EMP attack have been studied since the 1950's (extensive reports published) and have included two formal U.S. Congressional EMP Commissions (reports published in 2004 and 2008).

2008 EMP Commission Report States:

"The E3 pulse is similar in a great many respects to geomagnetic effects induced by solar storms.  Solar Storms and their impacts on electrical systems with long lines have been thoroughly evaluated and are known to cause serious damage to electrical system components at much lower levels than the reasonable possible E3 impact."

"System wide ground-induced currents in the transmission grid can by themselves cause system collapse.  They did so in March 1989 in Quebec.  At the levels expected in an E3 event, collapse would be much more likely and widespread."

"Commission analyzed the impact of a 100-year solar storm (similar to E3 from EMP) and discovered a very high consequence vulnerability of the power grid."  

"Steps taken to mitigate the E3 threat also would simultaneously mitigate this threat from the    natural environment."