Component-Component Transformer / Transformer / Transformer
1. Iron Core
Iron core serves to simplify the way flux, magnetic generated by the electric current through the coil. Made from thin metal plates which insulated to reduce heat (as the iron losses) generated by Eddy Current.
2. Transformer coil
Transformer coil windings are some insulated wire forming a coil or coil. Coil consists of a primary coil and secondary coils are isolated either towards or against the inter-iron core coil with solid insulation such as cardboard, etc. pertinak. The coil as a means of voltage and current transformation.
3. Transformer Oil
Transformer oil is one of the liquid insulating material which is used as insulation and coolant in transformers.
• As part of an insulating material, the oil must have the ability to resist breakdown voltage, whereas
• as transformer oil cooler must be able to reduce heat generated,
so with both the ability of the oil is expected to be able to protect the transformer from the disorder.
Transformer oil has the element or compound contained hydrocarbons are paraffinic hydrocarbon compounds, hydrocarbon compounds and aromatic hydrocarbons naftenik. Besides all these compounds, transformer oils still contain compounds called additive even though its content is very small.
4. Bushing
The relationship between the coil transformers with external network through a bushing that is enclosed by a conductor insulator. Bushing also functions as an insulator / conductor with insulation between the transformer tank. On equipped facilities for testing bushing bushing condition which is often called a center tap.
5. Conservator Tank
Conservator tank serves to hold reserves of oil and steam / air heating due to the transformer due to load current. Between the tank and a transformer which paired relays bucholzt gas will absorb oil production due to damage. To keep the oil is not contaminated with water, tip into the airways through the release channel / venting moisture absorbing media has on the air, often referred to as silica gel and he's not out polluting the surrounding air.
6. Transformer Cooling Equipment Help
In the iron core and coil - the coil will rise due to heat losses from copper. Then the heat resulted in an excessive temperature increase, this will damage the insulation, to reduce the excessive temperature rise transformers need to be equipped with tools or cooling system to channel the heat out of the transformer, the media used in the cooling system can be: Air / Gas, Oil and Water.
In a natural way, streaming media as a result of the temperature difference between the media and to accelerate the cooling of the mainstream media (minyak-udara/gas) by completing a transformer with fins (radiators). If desired distribution of heat more quickly, the manual way can be equipped with equipment to speed up the circulation of cooling media to pump the oil circulation pump, air and water cooling method is called force (Forced).
7. Tap Changer
Quality of electric power operations if its nominal voltage according to the provisions, but at the time of surgery may decrease the voltage so that its quality decreases, it is necessary to stress that the voltage regulator on obtaining the best conditions, constant and continuous.
For the transformer is designed in such a way that changes the voltage on the inlet / input does not result in changes in voltage on the exit / output, in other words, the voltage on the exit / output equipment. This tool is called a voltage regulator leads without termination charges, commonly called the On Load Tap Changer (OLTC). In general, OLTC connected on the primary side and the amount depends on the design and system changes the voltage on the network.
8. Respirator (Dehydrating breather)
As shelter expansion caused by heat insulating oil that may arise, then the oil collected on the tank is often called a conservator. On the surface of the oil conservator is sought must not be in contact with air, because humidity air containing water vapor will contaminate the oil even if the process lasts long enough contamination. To overcome this, the incoming air into a tank of oil to the conservator at the time of cold moisture requires a media vacuum, which is used usually is silica gel. Contrary if a transformer heat so when it shrinks it will suck air from outside into the tank and to avoid contamination by air humidity, we need a media that is used usually sucking moisture is silica gel, which is specifically designed for the purpose mentioned above.
9. Indicators
a. Thermometer / Temperature Gauge, this tool is used to measure the heat from the transformer, both primary and secondary coils heat the oil too trafo. This thermometer works on the basis of mercury (mercury / Hg), which is connected with a tube connected with the expansion and the degree of heat indicator needles.
Some thermometers combined with heat from the resistor (which is connected with the special current transformer, which is inserted in the middle of phase one phase) thus obtained is a relative indication of the heat is actually happening.
b. Surface oil / Level Gauge, this tool serves to high-level appointment of an existing oil in the conservator. There are several types of appointment, such appointment is with immediate estimate on how to install the glass on one side so it will be easy to identify the conservator oil level. While other types if the conservator is designed to complement such a balloon of elastic material and filled with ordinary air and is equipped with protective devices such as the respiratory system so that expansion and contraction of the oil-air balloon into the dry and safe condition.
10. Internal Protection Equipment
a. Bucholzt relays, use of gas detection relay (Bucholtz) in oil immersed transformers is to secure the transformer which is based on disturbances such TRANSFORMER: arcing, partial discharge and over-heating which generally produce gas. These gases are collected in the room will do the relays and alarm contacts.
Gas detection relays also consists of a piece of equipment that responds to the high oil flow abnormalities arising at the time of the transformer serious disruptions. This equipment will move the contact trip that is generally connected with the circuit breakers trip flows from the transformer installation.
There are several types of relays bucholtz mounted on a transformer, Relay type but used to secure space On Load Tap Changer (OLTC) with the same working principle is often referred to as Relay Jansen. There are several types such as relays buhcoltz but there is no gas control, the kind of pressure one uses the membrane / membrane bending tin so that when the pressure changes because they will work disruption, there is no alarm here, but a direct trip and on the same principle only using a safety pressure or pressure switches.
b. Jansen membrane, this means more work for the safety of pressure (Explosive Membrane) / bursting Plate. This works because the relay is more pressure inside the transformer due to interference, because the pressure exceeds the ability of the membrane / membrane attached, then the membrane will rupture and the oil will come out of the transformer oil caused by pressure
c. More pressure relay (Sudden Pressure Relay), a flash over or short circuit resulting in an oil immersed transformers, will generally be associated with a more pressure inside the tank, because the gas formed by decomposition and evaporation of oil. By completing a relay release more pressure on the transformer, then the more pressure that could endanger the transformer tank size is limited. If this pressure can not be eliminated within a few millidetik, then there is more heat to the liquid tank and a transformer to explode. Safety equipment should be quickly worked to evacuate the pressure.
d. Tank safety relays, safety relays work as if there is current flowing in the tank, due to phase disturbance to the tank or the installation of aids such as fan motors, motors circulation and aids the other, heating etc..
This current differential relay as a substitute for a safety relay system is usually mounted on the transformer tank is not equipped with the current transformer primary side and usually on a transformer with a small capacity. Transformer mounted on insulators so that is not connected to the ground and then using a cable which is passed earthing transformer insulation levels and flows with a small ratio and then connected to the relay
ground tank with a current transformer ratio between 300 s / d 500 with the secondary side only 1 Amp.
e. Neutral Grounding Resistance / NGR or Resistance Grounding transformer, is the resistance that is placed between the transformer neutral point to earth, which serves to minimize the disturbance current. Resistance mounted on the transformer neutral point is connected to Y (star / Wye).
NGR normally mounted on a neutral point of 70 kV or 20 kV, whereas at neutral point of transformer 150 kV and 500 kV direct digrounding (solid)
NGR Value:
Voltage of 70 kV = 40 Ohm
Voltage of 20 kV = 12 Ohm, 40 Ohm, 200 Ohm and 500 Ohm
Type Neutral Grounding Resistance
- Resistance Liquid (Water), ie its resistance material is pure water. To obtain the desired resistance value of KOH added salt.
- Resistance Alloy, namely nekelin article is made of metal and made in panels with a pre-determined resistance value.
11. Additional equipment for safety transformers
a. Firefighters, (typically for transformers - large transformer), a modern fire-fighting system at the transformer as it is now very necessary. An important function to prevent or extinguish a transformer fire as quickly as possible transformer in case of fire.
The cause of a transformer fire was due to short circuit the transformer secondary side so that the maximum current will flow. If the process lasts long enough and the relays do not operate. Meanwhile, not as a result of the operation of relays also set the time of opening of the PMT, the relay is damaged, and the DC source that does not exist, as well as damage to wiring systems.
Modern firefighting systems by reducing the oil system automatically so there are spaces where oxygen separator gas forcibly incorporated into the air space that has no oil so no burning oil, and further damage can be avoided, even if the condition becomes damaged transformer .
Oil removal process using gravity or pumps DC motor is a condition that is very risky, because only with an automatic valve controlled by the trigger of the switch due to the heat of the fire and close automatic valves on the valve pipe connecting the oil tank (the conservator) to the transformer (before bucholz relays), and the presence of oxygen gas separator (high-pressure nitrogen gas) is loaded through the pipe to be joined at the bottom of the transformer and then going into the chamber is not filled with oil.
b. Thermometer measuring direct, directly measuring Thermometer is widely used on high voltage installations / sub station, as in the control room, relay room, living room etc. PLC. Room temperature is recorded periodically on the form which has been prepared and evaluated as a material statement.
c. Thermometer measuring indirect, indirect measuring thermometers are widely used on high voltage installations / transformer that serves to determine the change of oil and transformer winding temperature. Oil and transformer winding temperature is recorded periodically / regularly, on a form which has been prepared and evaluated as a report.
12. Transformer Protection Relay and Functions
Type of relay protection in power transformers are as follows:
a. Overcurrent relay (over current relay), serves to secure the transformer against short circuit between phases within and outside the security area transformer. These relays are also expected to have complementary properties with more load relay, this relay also serves as a safety backup on the other installations.
b. Differential relays, relay serves to secure the transformer to short circuit fault happens in the area of safety.
c. Limited ground fault relay (Restricted Earth Fault Relay), the relay serves to secure the transformer to ground the transformer in the security area, particularly near the neutral point of interruption that can not be perceived by the differential relay.
d. Directional overcurrent relays, Directional Over Current Relay, or better known as overcurrent relays that have a certain direction is the Safety Relay working because of the current and voltage quantities that can distinguish the direction of flow disturbances. These relays have two pieces measuring parameters of voltage and current into the relay to distinguish the current direction forward or backward direction of currents, the neutral point earthing transformer using prisoners. These relays installed at 20 KV feeders.
This relay works based on the current source of ZCT (Zero Current Transformer) and source voltage of the PT (Potential Transformers). Source voltage of PT generally use a series of Open-Delta, but did not rule out there that use direct connections three phase. These relays installed on a network of high voltage, medium voltage, also on the safety of power transformers, and serves to secure the electrical equipment due to the disruption of phase-phase or phase to ground. To distinguish the direction of the current one should compare phase with phase voltages on the other.
e. Relay connections, is the angle difference between the current and the input voltage relays at power factor of one. Relay maximum torque angle is the angle difference between the current and the voltage on the relay which produces maximum torque.
f. Ground fault relays, relay serves to secure the transformer if ground fault occurs inside and outside the security area transformer. Direction relay circuit ground signal and operating require polarizing signal. Operating signal obtained from the residual current through the current transformer circuit (IOP = 3Io), while the polarizing signal from the residual stress. Residual stresses can be obtained from the secondary circuit open delta voltage transformer.
g. Ground tank relays, relay serves to secure the transformer against short circuit between the coils of phase with the transformer and the transformer tank is earthed neutral point. Worked as a safety relay in case the current flows from tank to tank due to interference or phase of the installation aids such as fan motors, circulation and auxiliary motors, heaters etc..
The security of this flow as a substitute for the differential relay, safety relay system because the tank is usually installed on a transformer that is not equipped with the current transformer primary side and usually on a transformer with a small capacity. Transformer mounted on insulators so that is not connected to the ground and then by using a grounding wire is passed through a transformer with the current level of insulation and a small ratio, then the tank is connected to the relay current transformer with ratio of soil (CT) between 300 s / d 500 with the secondary side only 1 Amp.
13. Announciator High Voltage Installation System
Announciator are indicators of abnormal events occurred during the installation of high voltage system, both individually and collectively. Announciator coincides with a relay that works because if there is abnormality in the equipment. Annunciator usually in form of written instructions under normal conditions there is no designation, if there is abnormality in the indicator lights are lit in accordance with the conditions of the system at that time. Collection of these indicators are usually referred to as announciator.
Announciator the most complete in the present moment is the installation of SF6 substations, because at the GIS system, a lot that needs to monitor conditions such as gas pressure, humidity of SF6 gas in each compartment, the contact position of PMT, PMS PMS line well, an STD or STD land etc. Rel. For that discussion would be taken from the system annunciator annunciatornya SF6 substations. like. Annunciator at bay (SUTT or SKTT), transformers and Koppel.
