third week

· See the maintenance of a battery charger in a substation

· Battery charger is used in VCB (vacuum circuit breaker) switchgear.

· The battery used is a wet battery, like often seen in a car.

· There are 25 of battery in one compartment.

· Total voltage across the battery is between 32.6V to 35.6V. The voltage across one battery is about 1.5V to 1.8V. If the voltage is sum up, it will get the total voltage across the total battery.

· The voltage from positive to earth is about 17.3V to 17.6V. The voltage from negative to earth is also about 17.3V to 17.6V.

· The water in the battery need to be added if it is inspected less.

· Multimeter is used to measure the voltage in the battery charger.

· There is also thermo scan process in this week.

· Thermo scan is a process to see the temperature and heat in each substation. The equipment used is very expensive.

· The heat in transformer, switchgear, LVDB and each cable can be seen.

· If the temperature is ±76 ºC, then it is okay. Otherwise, it is not okay and will be needed to be check.

· There were also ultrasonic test. It will detect noises in each things in substation such as humming, tripping

· Followed the SVR (salur atas voltan rendah) gang for three days.

· Unlike the pencawang gang, this group works with a much lower voltage area.

· Connected the cable connector in each houses because the cable is not connected well before.

· If the cable is not connected well, current will trip the cable and eventually will blow the circuit and it is very dangerous

· Going to TNB store in Perai. There were the place where the things like brand new transformers, switchgears, feeder pillar is placed.

First Week

• followed the maintenance gang
• checking current fault by using earth fault indicator(EFI)
• EFI is the faulty cable length is easy located by tracing the last indicator that has been tripped and the first indicator which has not tripped. The faulty section can be switched off and the rest of the cable can be put into operation again.
• The Led will be placed outside the substation so that it is easier for the technician to see which substation has tripped. For each EFI,they have different bits set to be set occording to the specifications given by the engineers. Each type of bit sets are representing the duration of time for the EFI to keep operating when trip happened.
• Learned about system, safety and things in pencawang elektrik (P/E) which is switchgear,lower voltage distribution board(LVDB) and transformer.
• get to know a few designs and brands for switchgear and how it operates
• transformers - a few specifications, has tap changer which will be set to 11 kV (number 3)
• After P/E, there is PAT or also known as pencawang atas tiang which is functioning as a P/E.
• In PAT we have transformer, drop fuse, black box, and also LVDB.
• See the powerful and dangerous model of switchgear, which is the vacuum circuit breaker (VCB). Battery charger is used to supply the VCB.The vacuum will cover the circuit from blow.
• There are relay in VCB. When trip occur,current produced was large,so the relay use a ratio to minimize the current.If the relay did not minimize the value of the current,it may cause damage to the relay and switch box.
• involve in cabling the earthing cable in a P/E. the cable need to be replace because the old cable has been stolen.
• Learned about how many LVDB should be place in one P/E.