Guardian products inject reactance and push power away from a given transmission circuit. PowerLine Guardians® are installed directly on each phase of the conductor. Power Guardians can be installed in a ground-based bank, on a tower or as part of a mobile deployment, all of which can be placed adjacent to or within the transmission right-of-way or existing substation.

The number of devices per phase is determined by the amount of compensation required as each device injects a fixed amount of reactance. This reactance addition depends on the product type and model. The devices can be remotely controlled over a secure wireless network or programmed to activate automatically based on current set points.

Explore the data sheets and tabs below for product-specific information and details on how this technology is deployed, controlled and operated.

Deployment Options


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Tower-based Deployment

This tower can replace an existing structure within a circuit or serve as a new dedicated tower in the middle of a span. Existing towers can also be modified to accommodate units. Utilities needing to replace old poles or towers can use this method to upgrade their infrastructure and simultaneously add power flow control capabilities to their system.

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Ground-based Deployment

This extremely high-density deployment can be constructed on a small footprint within an existing right-of-way, a substation or a dedicated parcel of land adjacent to the ROW or a substation.

Smart Wires works directly with the utility to determine the design that is best suited for a particular application.

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Mobile Deployment

The mobile deployment method is a containerized solution that can be fully installed and commissioned in 8 hours. Installation requires a very limited line outage.

Installation requires a very limited outage ranging from a couple of hours to a couple of days, depending on site conditions. This method is ideal for short-term and near-term needs such as construction & maintenance support, short-term congestion, transmission emergencies and bridge solutions.

The equipment and methods used for installing the mobile solution are dictated by the particular deployment site conditions and each utility’s requirements and standards. Smart Wires will work with each utility to determine the connection option best-suited for a particular application.


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Spread Deployment

This method is available for PowerLine Guardians and is best suited for relatively small deployments and/or circuits with sufficient length. Mounting PowerLine Guardians on a conductor is generally the fastest deployment option for utilities wishing to address power flow in a vastly compressed timeline.

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Compact Deployment

In this method, many more PowerLine Guardians can be installed on each span. Compact deployment usually involves reconductoring a small line section and/or installing a few new poles. This method allows utilities to choose a preferred location along a circuit, meaning they can completely avoid disturbing residential areas or environmentally sensitive regions.

Operating Modes

Each Guardian unit has two distinct modes of operation:

  1. Injection Mode – magnetizing reactance is injected onto the line. The magnitude of this magnetizing reactance is defined by the device rating. Guardians can transmit telemetry data in this mode.
  2. Monitoring Mode – no reactance is injected. Guardians can also transmit telemetry data in this mode.

If a Guardian in Injection Mode senses a line current which exceeds its rated tolerance, the unit automatically switches into monitoring mode within 1 millisecond.

Control Methods

While each Guardian unit operates independently (as described in the Operating Modes tab), utilities control deployments of Guardian devices using one of three methods. A deployment of Guardians only functions in a single manner at any given time. The Control Methods are defined by their levels of automation and communication requirements:

  1. Static – This is the simplest and most common control method for first and early stage deployments. The deployment of Guardians continuously delivers the desired level of reactance (the system is static) and does not require any backhaul communications. The level of injected reactance can be adjusted by using local communication methods and is typically adjusted on a seasonal basis to accommodate various reliability needs.
  2. Manual – This method is similar to static control, however backhaul communications are enabled. This allows for manual remote-control of the Guardian deployment by the system operator. Operators can change the Operating Mode (Injection vs. Monitoring) of individual and/or groups of Guardians. This enables real-time flexibility of power flow control.
  3. Set-point – With this method, no manual control is required, but backhaul communications are necessary. The deployment of Guardians operate autonomously, switching from monitoring to injection mode (and vice-versa) based on the real-time line current or conductor temperature. These set-points are user-defined and configurable. Any number of set-point configurations can be created by operators within the Smart Wires software platform.
Communication & Control

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The End to End (E2E) Communication and Control System (referred to as the E2E system) seamlessly interfaces with utility Energy Management Systems (EMS) and manages the operation of Smart Wires Field Devices (SWFDs).

Utilities operators control of the amount of reactance provided by the fleet of SWFDs at the EMS level. EMS commands are transmitted to the PowerLine Gateway over a secure communication channel. The PowerLine Gateway is an IT/SCADA device, located at the substation, which provides configuration, observation, control and asset management services for the SWFDs. The PowerLine Gateway supports multiple communication protocols – including DNP3, IEC 61850, 60870-5-104 and others – and transmits the utility’s EMS commands to the PowerLine Coordinator. The PowerLine Coordinator, an IT/SCADA device located either in the substation or in the field, manages the secure wireless network that is used for communication with the SWFDs.

Optional PowerLine Manager software runs on a server located in the utility data center. This software includes features such as remote access to all the diagnostic data from the SWFDs and the ability to perform remote software updates.

Once the SWFDs are programmed initially, each unit largely controls its individual reactance injection on the transmission circuit. The SWFDs detect faults and automatically bypass when the current is at fault condition levels.

The Smart Wires Difference

Smart Wires solutions offer key advantages compared to traditional approaches to infrastructure investments. All of Smart Wires products are modular in-nature, meaning that deployments can be fine-tuned to meet system needs. Should utilities require a different amount of power flow control at some point in the future, Smart Wires’ installations can be easily scaled up or down. Smart Wires solutions are quick to deploy, providing utilities with an installed solution capable of addressing emergency needs. Also, all products are designed to be easy to re-deploy. This means that if grid conditions change and power flow control is no longer needed on a specific circuit, the Smart Wires solution can be moved to a different location on the grid. This reusable investment is perfectly suited for addressing problems that are known to be short-term or temporary in nature.