Electricity needs to be transmitted over large distances. The power plant where electricity is made could be hundreds of miles away and power plants all across the country are connected to each other through the power grid. Electricity is made at the power plant and a current is sent through the transformers to amplify the voltage to push the power over these lengthy distances.
The electrical charge travels through transmission lines, reaching the substation. The voltage is then lowered so that it can be transmitted on smaller power lines. It then travels through these smaller distribution lines, entering our homes.
High Voltage – Keep Out
Substations have fences around them to keep people out with high voltage warning signs on them. The voltage on the power line coming into your home is 240 volts. The distribution line is usually 7,200 volts while the voltage inside the substation is energized at more than 100,000 volts. Substation technicians are trained to work in high-voltage situations and to understand the functions of the equipment such as the oil circuit breakers, vacuum circuit breakers, earth testing, gas circuit breakers, the disconnect switches, the reactors, capacitors, instrument transformers and power transformers among others.
All You Need to Design and Maintain Substations
Engineering companies supply electrical test instruments, power cable accessories, PAT test equipment among others as well as specialist electrical services and reports. These include the likes of oil testing reports, cable mapping and metering system design. They provide everything needed to construct and also maintain high-voltage transmission and distribution substations.
Substations have switching- and control equipment as well as transformers. Instrument transformers for metering purposes, for instance, need to possess a high degree of accuracy to ensure accurate billing, and it is, therefore, imperative to inspect instrument transformers at regular intervals. This is to ensure the transformers react quickly in the event of a fault. The importance of transformer tests shouldn’t be underestimated and risks such as mixing up connections can be reduced simply by testing before use. A range of transformer testing equipment is available such as frequency response analyzers, oil testing kits, transformer ohmmeters and others.
A visual check and inspection of electrical equipment is carried out on all electrical equipment. The main substation equipment testing procedures include –
- A.C. Supply checks
- D.C. Supply Checks
- Internal Panel Wiring
- Scheme Checks
Relays will be checked to ensure no dirt in the magnet gaps and all connections will be checked for tightness on the relays. All devices will be checked so ensure they are clearly identified with the general arrangement drawings.
An earth survey is also conducted for the substation to get a value for the site earth resistivity. Standard earthing tests are carried out during erection stage of the substation. Inter-panel bus wiring will be tested as well as multi-core cables. Batteries and chargers will also be checked to ensure they have been assembled correctly.
Technical staff are shown safety precautions when working on substation equipment –
- How to de- energise transformers, battery banks, switchgear and breakers
- Safety considerations when approaching any substation job
- Knowing the process of how to ground a piece of substation equipment, isolating and de-energising it
- How to mark the area of the substation that is de-energised and to know precisely where test procedures will take place
- The testing process will also include safety precautions to observe during maintenance activities including repairing insulator and changing oil
- The proper clothing and tools required when working on battery banks.
The Right Processes to Avoid Catastrophes
Electrical substation failures occur any time of the year but perhaps more frequently during summer, and these failures result in the need for emergency electrical services because of the main areas without electricity. If there are loose connections, for instance, you could be looking at a thermal breakdown that won’t just result in no electricity, but a major electrical substation failure.
This is why it is so important to schedule regular maintenance checks to avoid problems such as substation failure. To do this, safety programs need to be in place and only trained and authorised workers be permitted to perform any kind of electrical maintenance.
Safety Needs to Receive Priority
Substation equipment testing procedures are important for the substation system. It is essential that safety with substations be given priority to avoid catastrophes. For fault locating to be efficient, highly trained technical staff require expert knowledge while working on high voltage power generation as well as transmission and distribution systems and equipment.