What are the Tests and Maintenances That Should Be Done on High Voltage Lines?

High voltage lines are transmission infrastructures that form the backbone of the energy system, and the reliable operation of these structures depends on a regular maintenance program. For this reason, the tests and maintenance that need to be done on high voltage lines are not only operations that come into play after a malfunction occurs. The main purpose is to detect mechanical breakdowns, electrical weaknesses, environmental risks and security problems that may occur along the line before a failure occurs. Because a small defect in the transmission line may turn into a systemic problem, not a regional one, over time.

The first step in maintenance is always safety and planning. Operational preparation, access plan, approach distances, site permits and, if necessary, a power cut scenario should be determined according to which section the work will be done. Maintenance work on the high voltage line is not only an electrical risk; Working at heights involves additional risks such as open terrain, wind, soil conditions and mechanical access. Therefore, the maintenance approach must include both electrical safety and field operation safety.

Line patrols form the basis of the maintenance program. These patrols can be carried out on foot, by vehicle, when necessary, with air support or technological monitoring methods. Aim; It is to see tower structures, conductor status, insulator strings, shield wire, tree approach, environmental damage, corrosion and external intervention risks as early as possible. On a line that is not regularly patrolled, the fault is usually first noticed at the time of the outage. However, a good maintenance system aims to see line problems before failure occurs.

Control of tower and pole structures is one of the most critical topics in high voltage line maintenance. Access elements such as tower legs, connection bolts, cross members, cross members, rust areas, deformations, mechanical impact traces, anti-climbing structures, stairs and platforms should be carefully examined. It should also be checked whether there is settlement, soil opening, erosion, concrete cracks or anchor loosening in the foundation areas. Because the weakness in the carrier structure of the transmission line can have serious consequences as well as an electrical defect.

Conductors and conductor equipment are the electrical and mechanical center of maintenance. The conductor should be checked for broken wires, excessive wear, damage caused by birds or external factors, corrosion, out-of-lay condition, local burn marks and deterioration in joint areas. Jumpers, additional bells, dead-end and suspension equipment, spacers, vibration dampers and connection clamp areas are also part of this examination. Because in high voltage lines, the problem often occurs not only in the body of the conductor, but also in the equipment that carries or connects the conductor.

Insulator arrays are one of the most sensitive elements of the high voltage line. Defects such as contamination, cracks, fractures, surface marks, signs of corona, missing discs, fitting loosening, cuts or erosion in the composite body should be carefully monitored. The condition of the insulator surface directly affects line performance, especially in coastal, industrial or heavily polluted areas. Insulator cleaning, when necessary, should be considered as a dedicated part of the maintenance plan. Because surface contamination combined with moisture can seriously increase the risk of leakage currents and surges.

Shield wire or ground wire control should not be neglected. This conductor not only provides protection against lightning, but is also part of the overall mechanical and protective behavior of the line. Defects such as disconnection, corrosion, loosening of joints, loss of connection or external damage in OPGW types should be carefully evaluated. Likewise, tower grounding connections, down conductors and grounding continuity should also be included in the maintenance program. Because lightning performance depends not only on the top wire but also on how the current is transferred to the ground.

Sagging and clearance evaluations are of great importance, especially in cases of temperature change, heavy loading, icing or aged lines. If the conductor sags more than normal between the towers, the environmental approach distances decrease or the distance between phases becomes risky, this is a critical finding in terms of maintenance. For this reason, ground clearance, tree approach, structure approach and mechanical behavior in long spans should be regularly monitored along the line. Visible sagging differences should be verified with more detailed measurement and engineering review when necessary.

Thermal inspection is an invaluable diagnostic tool in high voltage line maintenance. Especially when joint points, jumper connections, clamp areas, terminal ends and metal-metal contact areas that may create high resistance are examined with a thermal camera, unnoticeable hot spots can be detected at an early stage. The purpose of thermal evaluation is not to see the absolute temperature alone, but to see the differences between similar phases and similar equipment. A significant temperature difference often indicates a loose connection, increased contact resistance, or hardware failure.

In some cases, UV inspection also provides important support. In particular, corona activity, surface degradation or high electric field effects on insulators and hardware may become more visible with UV-based inspection. This method is especially useful in evaluating some defects that are not clearly visible visually, especially on energized lines. However, UV inspection alone is not always sufficient; It gives stronger results when interpreted together with visual control and thermal evaluation.

Plant and line corridor management is a separate main topic of high voltage line maintenance. Tree approach, risk of branch contact, vegetation obstructing access to tower foundations, vegetation rubbing against guylines, and dense growth complicating maintenance access should be checked regularly. Corridor maintenance is important not only for outage prevention, but also for fire risk, tower foundation inspection and access to grounding elements. The environmental safety of the line often depends on the quality of corridor management.

Maintenance on high voltage lines is not just mechanical inspection; External influences should also be considered. The effects of bird-borne pollution, hunting bullet damage, third-party intervention, unauthorized construction, agricultural equipment approach, road clearing and extreme weather events should be included in maintenance records. Because such external influences may create risks that are not included in the design of the line but seriously affect the operational reliability.

Classifying and prioritizing critical defects is a fundamental part of maintenance management. Not every defect is evaluated with the same weight. While some problems require immediate attention, others can be placed on a planned maintenance schedule. Situations such as broken insulator, shield wire about to break, serious thermal anomaly, dangerous sagging or structural risk in the tower foundation have immediate priority. In contrast, light surface contamination or incipient corrosion can be resolved within scheduled maintenance. Making this distinction correctly is also important in terms of resource management.

At the end of maintenance, all findings should be recorded regularly. Patrol reports, photographs, thermal images, defect locations, tower numbers, environmental observations and corrective actions taken should be kept in a single maintenance history. Because high voltage line problems often grow with defects that develop over time, rather than suddenly. When trend monitoring is done, recurring problems in the same tower, corrosion concentrated in certain areas or environmental effects are seen more clearly.

In summary, the tests and maintenance that must be done on high voltage lines; It consists of regular line patrols, tower and foundation inspections, conductor and equipment checks, insulator evaluations, shield wire and grounding verifications, thermal and, when necessary, UV inspections, sagging and clearance checks, and corridor maintenance. A good maintenance system aims not only to fix the fault, but also to see the weak points of the line before the fault occurs. If high voltage line connections, MV/HV field suitability, transmission equipment controls and maintenance planning will be evaluated together in your facility HV/MV testing, maintenance and repair, on the project side LV/MV/HV project design and consultancy and business processes SA operation responsibility It is possible to progress in integration with services.