The AP-20 System

Accurate Phase Identification. . . Anywhere.

Avistar's AP-20 phase measurement system is a fast, easy-to-use tool for identifying phase and phase angle anywhere on your power system. Featuring complete one-person operation, immediate phase identification, and powerful features for remote work and GIS system-map integration, the AP-20 is by far the most capable tool in its class.

Click on any of the links below for additional information:

• Product Brochure
• Components
• Principles of Operation

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Features and Benefits:

• immediate, automated, on-the-spot phase identification when within cell range
• powerful remote work capabilities: stores 100 readings for as long as 4 days, then calculates and reports the phases automatically as soon as it finds cell service
• simple, one-person operation
• no phone calls to make, no codes to write down or type
• works on overhead T&D, on bare conductors;
  works underground for elbow test points and live-front parts for primary and secondary connections
• supports 120V - 500kV AC
• audible reporting (in addition to visible), so you can identify phase after phase while keeping your eyes on the hotstick and test points
• transfer of phase data to laptop in industry-standard CSV format, for easy import into your GIS based system map
• automatic correction for phase shifts
• faster than any comparable system

Common uses include:

• underground cable replacements
• map updates
• connection of new substations
• SCADA installations
• system expansion, optimization and load balancing
• switching procedures, particularly underground distribution
• verification of secondary PT connection phasing
• EMF modeling
• conversion from overhead to underground

AP-20 Users include:

• electric utilities
• large commercial, industrial, government and military facilities

Operational Description:

The AP-20 consists of a Reference Unit, Field Unit, and Hotstick Unit. The Reference Unit typically installs at a substation, plugged into a reference phase via a standard wall outlet. Using GPS broadcasts for timing information, it continuously records the exact times of the voltage zero-crossings. The Field Unit and Hotstick Unit go to the job site. The Field Unit receives readings via FM wireless from the Hotstick Unit and, like the Reference Unit, uses GPS as a timing reference.

The system compares the GPS time stamps at the test point with those at the reference location and uses this information to determine the phase angle at the Hotstick Unit's point of contact. Once the phase and phase angle are identified, the Field Unit displays them visibly and audibly. This is within seconds while within cell-service range. Outside of cell-service range, the Field Unit stores 100 readings for as long as 4 days, then automatically resolves and displays them for you as soon as you return to cell-service range.

EDM International, Inc. 4001 Automation Way Fort Collins, CO 80525 T: 970.204.4001 F: 970.204.4007