The difference between the regulator and transformer

We know that electricity is able to generate a magnetic field, the magnetic field also can be converted into electricity. Put on a coil with alternating current, the

alternating magnetic field is generated, then the alternating magnetic field through the other coil, the other coil will induce a voltage, which is the principle of

the transformer, the transformer and the two number number of turns of the coil; simply, the use of magnetic coupling transformer principle, all the original secondary

winding (coil) composed of the Voltage stabilizer across the coil is proportional to the size and the number of turns, so the primary and secondary coil turns This ratio

determines the transformer turns ratio. Obviously adapter is not the role of regulator, because the secondary voltage with primary voltage changes.
Regulator is to use the principle of negative feedback, so to speak, the tap water faucet open the half, at the head of the outlet fitted with a sensor that detects

the amount of water, if the water volume, and automatically will tap off a small point, if a small amount of water, it will automatically open a large number of taps,

so that the amount of water remains constant. Regulators principles generally true, there is one in the regulator can detect a change in output voltage circuit (error

amplifier inverting input resistor divider sampling circuit, which can now be reduced to only one integrated chip), when the output voltage changes, the output voltage

change is detected by the chip circuitry to provide feedback to the servo motors, and then by PW motor driven arm automatically adjust the location of the brush, so

that the output voltage is stable, which is the easiest regulator.
In summary said, there is no power transformers role of regulator, but the use of negative feedback can be designed with the role of regulator of the transformer, which

is no problem, but the general power transformer is not the case. The use of the transformer in a certain range of output voltage change is small, and we have not a

concept of said regulator.
All regulators, have taken advantage of the same technology to achieve a stable output voltage, output voltage by connecting to the error amplifier inverting input

resistor divider sampling error amplifier inverting input connected to a reference voltage. Always try to force the error amplifier input equal to its ends. To this

end, it provides the load current to ensure stable output voltage (ie, negative feedback)
Regulator type more common regulator include: automatic AC voltage regulator, purifying power exchange regulator, regulator parameters, high-power compensation power

regulator, non-contact smart power supply .
Telecommunications sector electromechanical systems through modern electronic technology and equipment to achieve the modernization of management, which involves

communication technology, electronic technology, automatic control, computer technology and other subjects, with technology-intensive, high-tech, high-performance

features. Power is the basis of mechanical and electrical equipment, power supply out of the question, will bring a series of problems, or even interrupted. Therefore,

under realistic conditions on many devices, including electrical equipment, precision instruments and equipment imports made stringent requirements, the relevant

departments in order to improve the reliability of the power supply system, in front of these devices increase the corresponding voltage regulator, power supply, power

compensated power voltage regulator with its economic and practical advantages in the distribution of widely used.

The role of the regulator

Regulator is able to automatically adjust the output Voltage stabilizer f the power supply circuit or equipment, the regulator's role is to be volatile and non-use of electrical

equipment requires a supply voltage stabilized at its set value range, the various circuit or electrical equipment can be rated working voltage to work properly. All

regulators are implemented using the same technology of the output voltage to a regulated output voltage by connecting the inverting input of the error amplifier

resistor divider sampling, the error amplifier's noninverting input connected to a reference voltage Vref. Here we look at the role of the regulator.
The initial power regulator is by beating stable voltage relay. When the grid voltage fluctuations, the power transformers  egulator circuit starts automatically corrected, so that

the internal relay. Forcing the output voltage remains near the set value, the advantages of this circuit is that the circuit is simple, the disadvantage is the

regulator accuracy is not high and beat every relay shift will occur once the power supply is interrupted and sparks momentary interference.
The latter is now the regulator is generally industrial regulator, industrial regulator to do is to use induction voltage adjustment, no contacts at linear load buck

adjust voltage adjustment, no frequency offset shift and surge, causing the load to the input power quality the same. High efficiency and a wide range of industrial

safety combination of parts that can withstand harsh temperature, humidity, vibration and dirty environments.
Mainly by regulating the regulator circuit, control circuit, and the servo motor, etc., when the input voltage or the load changes, the control circuit for sampling,

comparing, amplified, and then drives the servo motor rotation, so that a change of position regulator Brush by automatically adjusting the coil turns ratio, so as to

maintain the output voltage stability. Larger capacity regulator, also uses voltage compensation principle.
With the rapid development of society, increasing electrical equipment. But the power transmission and distribution facilities, aging and development lags behind, as

well as poor design and other causes of insufficient power supply voltage is too low is not the end user, and users are often high voltage thread on voltage electrical

equipment especially for demanding high-tech and precision equipment, like a time bomb.
Speaking of the role of the regulator, as a public utility power grid system, above all kinds of loads connected to the tens of thousands, some of the larger

inductive, capacitive, switching power supply, the load is not only to get electricity from the grid, will in turn impact on the power grid itself, worsening the grid

or local grid power quality, resulting in the mains voltage waveform distortion or frequency drift. Another unexpected natural and man-made disasters, such as

earthquakes, lightning, power transmission system is open or shorted, will endanger the normal supply of electricity, thus affecting the normal work load.
Unstable voltage will cause fatal injury or equipment malfunction, affecting production, resulting in delivery delays, inconsistent quality, and many other losses.

While accelerating the aging of equipment, affecting life and even burned parts, so that the owners faced with distress or in need of repair will shortly update the

device, a waste of resources; seriously, security incidents, causing incalculable damage.
Regulators For voltage electrical equipment especially for demanding high-tech and sophisticated equipment is essential, which also prompted us to ask us to develop

high-tech and more advanced regulator to meet a variety of instruments and equipment needs. Therefore, we should know to use the regulator, but also to understand the

role of the regulator.

The main types of voltage transformers

⑴ at the installation site can be divided into indoor type and outdoor type. 35kV and below, made more indoor type; 35kV or more is made of outdoor type.
⑵ Press phases can be divided into single-phase and three-phase, 35kV and above can not be made of three-phase.
⑶ can be divided by the number of winding double and three-winding voltage power transformers ,  three winding voltage transformer in addition to primary and basic secondary

side, there is a set of auxiliary secondary side for ground protection.
⑷ Press insulation can be divided into dry type, cast type, oil-immersed and inflatable. Dry-type voltage transformer simple structure, no fire and explosion hazard,

but a lower dielectric strength, applies only to the following indoor 6kV devices; cast voltage electric transformer compact, maintenance side

It is suitable for 3kV ~ 35kV indoor power distribution unit; immersed voltage transformer insulation performance is good, can be used for more than 10kV outdoor power

distribution unit; inflatable voltage transformer for SF6 fully enclosed appliances.
⑸ divided according to the principle, can be divided into electromagnetic voltage transformer, capacitor voltage transformers and electronic voltage transformer.

The use of current transformers

A) current transformer wiring should comply with the principles in series: the first winding in series with the circuit under test should be, while the secondary

winding of the transformer load current with all instrument series
2) Press the measured current size, select the appropriate changes, otherwise the error will increase. Meanwhile, the secondary side must be grounded at one end to

prevent the insulation being damaged, one side of the low pressure side of the high pressure fleeing into the secondary, resulting in personal and equipment accidents
3) Open the secondary side is absolutely not allowed, because once open, the primary current I1 all become magnetizing current, causing φm and E2 surge, causing

excessive core saturation magnetization, severe fever and even burned coil; while over-saturation magnetization of the magnetic circuit after , the error increases.

In normal operation the current transformer, the secondary side is similar to a short circuit, it is suddenly open, the value is very small excitation force by the

sudden change of the value of large value, the magnetic flux in the core presents a serious saturated flat wave, so the secondary winding of the magnetic induction

through zero

A very high spire wave, its value can reach thousands or even tens of thousands of volts, endangering the safety of staff and instrument insulation.
In addition, the secondary side of the open circuit voltage of the secondary side of several hundred volts, when it comes to electric shock. Therefore, the current

transformer secondary side switches are available in short, to prevent secondary side open. During use, the secondary side should immediately removed once the open-

circuit load, then

, And then deal with power outages. Everything handle before reuse.
4) In order to meet the measurement instrument, relay, breaker failure judgment and failure filtering device needs, generators, power transformers , outlet, bus section

breakers, circuit breakers, circuit breakers are located bypass 2 to 8 of the current transformer secondary winding

Makers.
5) For the installation of protective current transformer locations should try to eliminate the main protection device is not protected zone settings. For example: If

two current transformers, and the location permit, should be located on both sides of the circuit breaker, the circuit breaker is in the scope of cross-protection

among
6) In order to prevent pillar type current transformer bushing flashover caused by bus fault, current transformers are usually arranged in the circuit breaker or

transformer side outlet
7) In order to reduce the damage to the generator internal fault, means for automatically adjusting the excitation current of electric transformer shall be arranged on the

outlet side of the generator stator winding. In order to facilitate analysis and incorporated into the system before the discovery of the generator internal fault

current transformer used for measuring instruments

Device should be installed in the generator neutral point side.

Zero sequence current transformer action principle

Zero sequence current protection is generally suitable for use in TN grounding system. Because when occurs a phase to ground when the TN-S system Id loop impedance including the phase line impedance Z1, PE line impedance ZPE and contact impedance Zf, ie Zs = Z1 + ZPE + Zf; For TN-C system, Id loop impedance including the phase

Line impedance Z1, PEN line impedance ZPEN and contact resistance Zf, ie ZS = Z1 + ZPEN + Zf; For TN-CS system, Id loop impedance including the phase line impedance Z1, PEN line impedance ZPEN, PE line impedance Zf ZPE and contact resistance , the ZS = Z1 + ZPEN + ZPE + Zf, can generate a single-phase

Ground fault current Id = 220/ZS, no larger than a three-phase fault current imbalance, as long as the appropriate setting, you can detect a ground fault occurs zero sequence current in order to cut off the fault circuit. The IT systems are generally used for power supply reliability is higher

For single phase power supply Circuit breaker immediately cut unnecessary, but need to send insulation damage monitoring signal to maintain continued supply of industrial and mining enterprises for some time within the unworthiness of the neutral phase three-wire distribution lines. When single-phase ground when flowing through the fault line zero sequence

Current system-wide non-fault system capacitive currents, which can easily detect the ground fault current, it can be used zero-sequence current protection device to monitor the relative first ground fault. TT earthing system is often used in industry, agriculture, civil lighting, power supply mix

Three-phase four-wire power distribution system, often find the three-phase current imbalance greater when the event of a phase to ground, Id loop impedance including the phase line impedance Z1, PE line impedance ZPE, load side grounding resistors RA and power side grounding resistor RB, contact impedance Zf, ie

ZS = Z1 + ZPE + RA + RB + Zf, the earth fault current Id = 220/ZS, the RA + RB >> Z1 + ZPE + Zf, and RA + RB values ??are generally larger, it is clear ring system failure TT Road impedance of the resulting single-access fault current Id, far less than the current imbalance is difficult to check

Measure the fault current, it does not apply to TT earthing system.
For the zero-sequence current protection zero sequence CT installation process must comply with the relevant standards. For IT earthing system, as a result of single-phase ground fault, earth fault currents may not only along the cable back into the surface of the conductor, but also could not fault along the cable

The conductor surface flow back, it must be installed by the cable head to ground zero sequence CT, so as to ensure the faulted phase and non-fault phase current through the ground capacitance, which can prevent external fault protection device malfunction, but also to ensure failure device reliable action. For

IT earthing system, generally installed on the neutral line N zero sequence CT, on the low pressure side of the zero-sequence CT busbar must be installed in the neutral line N and the work of ground (or repeating ground) between the busbars. Such as zero-sequence CT installed in the N line distribution panel busbars, power distribution panel as gold

Metal enclosure generally associated directly with the ground electrode, when the bus is shorted to ground occurs, the resulting fault current Id of the metal shell along the distribution screen → → ground current electric transformer neutral point, without passing through the zero-sequence CT, reach The demands of the protection function, which is in

When the construction site is easy to neglect.

Voltage transformer Precautions

Voltage transformer (PT) and current transformer (CT) is an important electrical power system equipment, which bears the high and low pressure systems and high voltage isolation between the amount of functions to convert low voltage. The wiring is correct or not, the system protection, measurement, monitoring and other equipment

Normal work is extremely important. In the new installation PT,power transformers commissioning or replacement PT, CT secondary cable, using the polarity of the test method test PT, CT wiring is correct, it is already an indispensable protection staff working procedures.
Avoid reverse polarity is to find the transformer input and output of the "dot end of the" specific method is the "point of polarity." This example shows how to point the current transformer polarity. The specific method is the multimeter connected to the output transformer secondary winding,

Multimeter hit the DC voltage profile; Then a battery of negative fixed at a current transformer output wires; reuse batteries positive to "point" of a current transformer input leads, so that the transformer primary mcb circuit breaker will generating a + (positive)

Pulse current; while observing pointer multimeter hands which direction "Offset", if the multimeter's hands shifted from left to right from 0, j namely hands "positive start" to show that you access the "current transformer input "and" Analog Multimeter positive terminal connection

A current transformer secondary output "is the same name as the end, and this connection is called a" positive polarity "or" minus polarity "; if the multimeter's hands shifted from right to left from 0, ie hands" anti-Kai "to show that you access" current transformer input "and" Pointer

Multimeter positive terminal connected to an output terminal of the current transformer secondary "is not the same name as the end, and this connection is called a" reverse polarity "or" plus polarity. "