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The Evolution of Success: Arizona Public Service

Thirteen years ago, that is what Arizona Public Service (APS) initially invested in a PdM program. Today, the program has evolved into seven technicians, utilizing over 50 different non-destructive testing (NDT) pieces of equipment, in nine areas of the department. As the PdM team and the company simultaneously grew, effective work management systems, communication systems and structures were created.

APS is the largest electric utility company in the state of Arizona. APS provides service to over 1.1 million customers within 35,000 square miles in 11 of the 15 counties in the state. APS generates 6,400 net megawatts and owns over 35,000 miles of transmission and distribution lines. The company has been serving Arizona’s energy needs for more than 126 years.

Scott Alford, the original reliability coordinator, now leads a team of seven technicians within the predictive maintenance department. The team focuses on overhead line reliability, underground equipment inspections, substation inspections, substation transformer surveys, radio frequency interference, pump vibration, Sf6 leak detection, corona detection and ground grid integrity testing.

Since inception, APS has seen over $20 million in cost avoidance benefits from predictive maintenance alone. Cost avoidance and improved reliability are some of the team’s greatest accomplishments, but safety is always the number one priority. The group proudly has not had a recordable event since the department’s beginning.

The team of technicians is a very diverse, yet focused group. As technicians are added, it is preferred that they have specific backgrounds in education or work experience. The technicians must have a proactive attitude, with an understanding of our industry and strong purpose as a PdM group. The ideal technician will frequently think outside the box and be self motivated to investigate abnormal equipment and situations related to the team’s areas of focus. All technicians complete formal classes and obtain certifications in various areas, including thermography, vibration and airborne ultrasound among others.


The two-person overhead reliability team uses a custom fabricated, state-of-the-art PdM vehicle to scan overhead lines while traveling down the road. The 4WD vehicle is equipped with an infrared camera, a corona camera and a wide angle digital camera with zoom. The team also utilizes a helicopter to fly over rural statewide transmission lines looking for anomalies. To date, the team has found in excess of 870 anomalies while patrolling over 7,700 miles of line throughout Arizona.

Underground equipment checks consist of thermal and visual inspections. Currently, these inspections are focused on APS’s key customers. The team has collected data from anomalies found and preventable outages over the last 18 months. A future goal is to have a dedicated team to inspect all underground equipment.


The PdM team performs infrared substation inspections on over 400 substations statewide. All of the substations are tier rated and the frequency of annual inspections for each substation is based on that rating. There have been over 1,700 anomalies found in APS substations using infrared cameras. APS also performs corona inspections in many of its substations. A yearly corona scan is scheduled in each of the company’s high voltage (115kv and above) substations. Any additional scans are based on “for cause.”



A substation transformer survey consists of collecting acoustic emissions data; vibration readings on the main tank and pumps; sound level data; a dissolved gas analysis (DGA), as required; a visual inspection; and collecting other pieces of information. The transformers are baselined, but also surveyed for cause when necessary. The high voltage transformers are equipped with an online DGA monitoring system. APS also has an on-site laboratory staffed with two chemists for manual DGAs. The PdM team utilizes its own portable DGA unit for immediate on-site results.

The transformer pumps have a set route and frequency for vibration readings. The frequency in which a pump is tested is increased or decreased based on results from the data collector.


All of the company’s radio frequency interference (RFI) complaints are also directed to the PdM department. The PdM team includes a dedicated RFI technician. This position focuses on external customer service. The PdM team’s RFI technician has been successful in finding even the most unique and complicated sources of RFI, many of which are not generated by APS equipment.

Never being satisfied with mediocrity, APS’s PdM team continuously seeks new and improved NDT equipment. In 2012, the team successfully launched a new ground grid integrity testing program. The new program has already identified several missing, corroded, or broken bonds within substations, therefore improving the safety of the substation crews and equipment. New predictive monitoring equipment was just purchased and allows the team to remotely monitor and record data in oil-filled equipment using 16 independent sensors.

The PdM department maintains an extensive database. This database is used to assist in cost avoidance, trending, planning and scheduling. The database is extremely organized. Even to the untrained eye, an employee would be able to access and view the information with a great deal of understanding almost immediately.

In order to maintain consistency and excellence, the PdM team has documented a procedure for each type of inspection or test. The group also has developed technical application guides (TAGs) for a majority of these. The documents are readily available to be read, reviewed and updated by any of the department’s PdM technicians.

For a long time, APS has used a computerized maintenance management system (CMMS) that plays a crucial roll in the PdM department. The software is used to schedule and issue work orders for planned maintenance (PM) inspections and testing. The team also utilizes it for condition-based maintenance tracking.

APS has two additional pieces of software that work alongside the CMMS for any anomalies that the PdM team finds. PDIQ is a custom APS program that manages all aspects of a substation. This application is available to the entire organization, allowing critical information to be entered into the system. This allows APS to view the overall health status of any substation or asset. Additionally, APS has deployed a corrective action request (CAR) system. The company can track any unsatisfactory condition more efficiently at all levels. This system is also configured to trend more accurately and consistently. Along with the company’s aggressive root cause analysis program, the CAR system is just one more tool in the arsenal.

PdM members have received formal root cause analysis training. In addition to this, APS has developed a separate in-house root cause analysis certification program. All PdM team members either have attended the in-house program or are scheduled to attend.

The PdM department’s annual goals are tracked using key performance indicators (KPIs). The team has a KPI for each month and year for the multiple NDT areas. The team is proud to report that 100% of the KPIs were completed in 2012.

The APS PdM team strongly believes that communication and customer satisfaction are the key factors of success. Besides utilizing CMMS, PDIQ and the CAR system, the team strives to maintain the highest level of customer satisfaction not only in communicating anomalies, but in giving and receiving feedback from various maintenance departments. When the unexpected request or emergency occurs, the technicians immediately respond, coordinate and work outside of their scheduled PM.


The PdM team has mission and vision statements in place, including an aggressive 10-year road map outlining future success. The group continually challenges itself to find new ways to improve safety, reliability and customer service for the company. This positive attitude has allowed the department to achieve the Infrared Program of the Year Award in 2010 and the Best Electrical Maintenance Reliability Program of the Year Award in 2012. The APS PdM department strives in looking forward, always searching for ways to grow in this ever-changing environment.

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