PRAM – What is it really and what does it help?
The PRAM laboratory is in the form of a van fully equipped and adapted to have very modern equipment that helps to check and test the installations before they are put into operation or in most cases to check, detect defects in existing installations.
PRAM works must be done according to very strict procedures that are followed exactly, according to EU standards. For electricity we must not have FEAR but respect and let technology and specialists check and solve any problems that may arise.
The electricity has a great influence and power in our daily life. Many people can suffer due to lack of maintenance of the facilities, due to lack of quick reactions and prompt intervention.
Also, most of the fire cases occur due to installations that are not periodically verified by PRAM and therefore short circuits can occur and lead to fires and unfortunately victims. The laboratory helps to identify the defect and put it into operation, restoring the power supply as quickly as possible.
The equipment in the PRAM laboratory is very complex, it detects, identifies problems with cables (underground, aerial installations etc). Each high voltage pole, even from the top of the mountain, has been measured and checked, but it needs maintenance because weather conditions can damage the installations. PRAM is the one who sees where the problem is, in safe conditions, before performing maneuvers and rehabilitation of the installation.
Examples in which non-compliance with this procedure leads to considerable damage in the energy sector:
- TULCEA COUNTY WIND FARM. In 2009, 6 wind turbines with a total value of 18 million euros caught fire because platinum discharging copper plateaus were not installed. In simple language, tens of millions of euros were invested, but the PRAM check was not done when the turbine was grounded and when lightning struck the wind turbine the electricity had to be discharged into the ground through that copper plate with a value of 50 euros. The current could have been dissipated and had a place to discharge in the river-washed sand that has properties in this respect. Due to the lack of PRAM measurements and non-compliance with the execution procedure, 6 wind turbines caught fire because they were connected in series.
- OLT COUNTY PHOTOVOLTAIC PARK. The evacuation line to the transformation station (underground, at the roadside) was executed very well, in conditions of maximum quality, but later the national road was widened with another lane. Hitting the existing cables during the road works lead to the operation of the park at a minimum capacity. The laboratory allowed us to identify the hit cables, to move the existing cables by sleeve and restore the full capacity of the park in less than 12 hours.
Periodic verification is provided by law as follows:
- Low voltage installations (except poles): once every 2 years;
- In underground operations (for local ones): twice a year;
- In underground operations (for the general network): once a year;
- In very dangerous environments: once a year;
- Checking the degree of corrosion of earthing installations: after 10 years from burial and then at least once every 5 years;
- In underground installations and in local earthing installations: at least twice a year;
- On general earthing networks: at least once a year.
There are two types of PRAM checks, depending on how often they are performed, namely:
- PRAM checks carried out before switching on the electrical installation, respectively checking the insulation resistance of the electrical conductors;
- Periodic checks – once every 6 months or annually, checks that can be performed with the electrical installation in operation, in charge.
Other PRAM technical usage:
- Checking the continuity of the null from electrical panels to machines and sockets: we check PRAM low voltage electrical installations, with the issuance of bulletins recognized by Labor Protection, Consumer Protection;
- Measurement of the dispersion resistance at the earthing of the lightning rod: periodically, once or twice a year, the operation in good condition of the lightning rod is checked, respectively the measurement of the dispersion value of the afferent grounding, which must not exceed 4 ohms, regardless of the condition of the ground – wet or dry.
- Checking the insulation resistance of conductors: checking the insulation resistance is done by applying high voltage to the conductors, so that it can be certified whether they withstand any shocks that may occur in the future. This is done before the electrical system is switched on and prevents a short circuit or even a fire.
- Checking the continuity of the protection null from the equipment and the earthing belt: checks shall be made to verify that there is a physical connection, through a properly calibrated conductor or through the Ol-Zn flat strip, between the housings, supports or control panels of the machinery and the earth socket corresponding to the production area concerned.
PRAM cable operations:
- Route identification
- Length measurements
- Identification and location of defects in low and medium voltage cables (several detection variants patented by Seba: Arm, ICE, decay, Arm burning, etc.
- Tess with Dc voltage up to 80kv
- Vlf tests (very low frequncy0.1 Hz) 54kv
- Controlled combustion
- Force burning (for changing the configuration of the defect) in the case of wet sleeves when it is impossible to detect.
- Grounding dispersion resistance
- Dispersion resistance for lightning rods
- Continuity connections for earthing belt protection
- Loop impedance, short circuit current
- Phase sequence
- Testing of DDR, RCD differential protections
- Testing of electrical insulation materials: gloves, boots, electrical insulation mats
- Insulation resistance for power and control cables
- Voltage measurement
- Sonometry, Light flux measurement
- Check / test PRAM insulation resistance of gloves and electrically insulating boots
Self- laboratory defectoscopy for underground electrical cables, PRAM checks (three-phase) – main equipment’s:
- Command and control unit: NSF 8 operation panel with device selection switch and the FU / EP security system with appropriate signaling:
- Separation transformer
- Reflectometer, TELEFLEX VX – 80kV high voltage module (ARMslide technology) + high power combustion, BPS 5000:
- Shock wave generator, SWG 1750/SWG 1750CD (1750 Joules/ 3500 Joules)
- Spring stabilization equipment, LSG 300
- Fixed audio frequency generator, FLG 200 (200W)
- Portable audio frequency generator, FLG 12 (12W) – combined portable receiver, FLE + Digiphone
- Fault locating system in cables with PD (partial discharges), PD Scan
- Current and voltage source for PRAM checks, RAPTOR C05 – 1000V megohmmeter, MIT 420/2
- Built-in Siroco system for heating equipment in the cold season – auxiliary generator – battery inverter for autonomous power supply