How to operate the complete set of general frequency conversion series resonance test equipment?

1. Wiring according to the wiring diagram of the frequency conversion series resonance test device.

2. The excitation transformer is connected in parallel or in series with high voltage, and the excitation transformer to the reactor needs to be connected with a high-voltage wire.

3. Turn on the power supply, set the test voltage and time as required, start to set the power to 5% 10%, the frequency to 30Hz, the protection current to the maximum current value, and set the reactor inductance.

4. After the parameters are set, select manual or automatic test according to your needs, if you choose manual mode, you need to manually find the frequency, when the highest voltage reaches a certain frequency point is the resonance point, press the confirmation button, and then manually adjust the required test voltage of the test frequency, the instrument will automatically time, and automatically return after the timing is over, if you choose automatic test, the instrument will automatically find the frequency, boost, timing and automatically return.

5. After the test is completed, the test result will be automatically displayed.

Portable variable frequency series resonant withstand voltage test device is mainly used in the following aspects:

AC withstand voltage test of KV-500KV high-voltage cross-linked cable.

KV-500KV transformer power frequency withstand voltage test.

3. AC withstand voltage test of GIS and SF6 switches.

4. AC withstand voltage test of generator.

5. AC withstand voltage test of other power high-voltage equipment such as busbar, casing and transformer.

The requirements are different, ** different. For example, only 6kV, 1km cable series resonant withstand voltage equipment is considered and 500kV, 5km cable, 500kV

GIS and SF6 switches, disconnector series resonant withstand voltage equipment, configuration, weight, and high quality will be very different. The above is selected from Shanghai * Dafan * Electric.

How it works:

The working principle of the frequency modulation series resonance test device is wired, the AC 220V power frequency power supply, the voltage adjustable at the frequency conversion control unit is output at 30 200Hz, and it is sent to the excitation transformer, and the voltage is boosted to 0 1000V, and the resonant reactor L and the tested product CX form a high-voltage main harmonic circuit, and the capacitor voltage divider is a pure capacitive type, which is used to measure the test voltage. First, a lower voltage UE is sent to the main resonant circuit by the frequency conversion control unit through the excitation transformer, and the output frequency of the frequency conversion control unit is adjusted, and when the frequency meets the condition l=1 c, the circuit reaches the resonant state. At this time, under a small excitation voltage UE, a voltage UCX dozens of times that of UE can be generated on the CX of the test product.

The frequency conversion test system works on the principle of series resonant circuit. The resonance point is achieved by adjusting the frequency of the frequency converter to the natural frequency of the series resonant circuit. After the loop is resonated, the output voltage waveform is a pure sine wave, and the frequency of the system depends on the L-C parameters of the loop.

The reactance value of the reactor is adjustable, and the frequency of the system depends on the size of the load capacitance, as shown in the above formula. According to the size of CX, the inductance L value of the reactor can be adjusted appropriately, so that the resonant frequency is fixed within a required range, so as to meet the experiment of the sample that must be tested under the power frequency condition.

According to the principle of series resonance, Wuhan Sanxin Electric Power has designed a lightweight and easy-to-operate test equipment.

The complete set of frequency conversion series resonance test device mainly refers to the voltage and current of the series circuit reaching the same phase, that is, the inductive reactance of the inductor and the capacitance reactance of the capacitor in the circuit are equal, so that the circuit presents pure resistance characteristics. In the case of a given terminal voltage, a large current will appear in the circuit, and the active power consumed in the circuit will also be large.

The impedance imaginary part of the circuit of the variable frequency series resonance test device is equal to 0. Therefore z=r+jx, x=0, z=r, so i=u z=u r.

1. Resonance definition: the energy of L and C components in the circuit is equal, when one of the reactive elements in the circuit releases energy, the other reactive element must absorb the same energy, that is, resonance will occur between the two reactive elements.

2. The circuit produces resonance. There must be two components: inductor L and capacitor C.

3. When resonating, the corresponding frequency is the resonant frequency or resonance frequency, which is represented by fr.

4. The conditions of the series resonant circuit, when XL=XC, the resonance conditions of the RLC series circuit.

5. Whether it is series resonance or parallel resonance, when the resonance occurs, a complete energy exchange is realized between L and C, that is, the released magnetic energy is completely converted into the electric field energy stored in the capacitor, and at another time, the capacitor is discharged, and then converted into the magnetic energy stored by the inductor.

6. In the series resonant circuit, the energy exchange is carried out with the change of voltage polarity due to the same current flowing through the series of L and C in series. In a parallel circuit, the voltages at L and C are the same, and the energy conversion indicates that the current phases of the two components are opposite.

7. The inductance and capacitance are still two components during resonance. Otherwise energy exchange cannot take place, but from the point of view of equivalent impedance. It becomes an element, a resistor with a value of zero or infinity.

Respondent: Huatian Power.

The complete set of variable frequency series resonance test device is to use the principle of series resonance, use the excitation transformer to excite the series resonance loop, adjust the output frequency of the frequency conversion controller, make the loop inductance L and the test product C resonate in series, and the resonant voltage is the voltage added to the test product. Variable frequency resonance test device is widely used in electric power, metallurgy, petroleum, chemical and other industries, and is suitable for the handover and preventive test of large-capacity and high-voltage capacitive samples.

Baoying high-power power equipment factory.

The variable frequency series resonant complete test device is composed of a variable frequency power supply, an excitation transformer, a high-voltage reactor and a capacitor voltage divider. The capacitor of the tested product and the reactor form a series resonant connection mode; The voltage divider is connected in parallel on the test piece, is used to measure the resonant voltage on the test piece, and is used as an overvoltage protection signal; The frequency modulation power output is coupled to the series resonant circuit through the excitation transformer to provide the excitation power of series resonance.

The test methods of the complete set of frequency conversion series resonance test devices include (1) cable test ultra-low frequency method, (2) cable test resonance withstand voltage method, (3) cable test oscillation voltage method, (4) cable test and inductive resonant pressure resistance method, (5) cable test parallel resonance method, (6) cable test series resonance method six methods, this paper mainly introduces the three methods of cable AC withstand voltage test.

1. Ultra-low frequency method.

The commonly used is the withstand voltage test, due to the large capacity of the cable, the capacity of the test transformer, the power frequency test is required, and a considerable test power supply needs to be provided on site to provide reactive power for the cable, this method is not suitable for field use. Therefore, the use of ultra-low frequency as the test power supply can greatly improve the capacity of the test transformer. The theoretical capacity is 1 500 times the power frequency, which is easy to implement in the field.

However, this method is not effective in detecting the main and secondary insulation defects of extruded insulated cables such as cross-linked polyethylene (XLPE). At present, this method has been applied to the testing of medium and low voltage cables.

Second, the voltage swing method.

DC charging cable, inductor discharge voltage resistance to reach a certain gap to obtain a damping oscillation voltage, main insulated cable and accessories for defect inspection. This method is more effective than DC voltage testing, but there are still some problems, the oscillation voltage attenuation is present when it is difficult to meet the needs of long cables, and these two voltage cables have a higher frequency of greater damage.

3. Vibration withstand voltage method.

The method of resonant stress test is to change the inductance and frequency in the test loop, so that the loop is in a resonant state, which can meet the test requirements of high voltage and high current. The resonant withstand voltage method is divided into frequency modulation type and frequency modulation type according to the adjustment method. According to the resonance mode, it is divided into series resonance and parallel resonance.

1. The resonance withstand voltage of the inductive cable is achieved by adjusting the inductance of the reactor in the reactor and the capacitance of the cable at the resonant frequency (50 Hz), and the test requirements are realized.

2. By changing the output frequency of the test power supply, the reactor with fixed inductance in the circuit can resonate with the test product to meet the test requirements.

3. Cable and resonant series method, when the current of the test transformer meets the test requirements, and the voltage does not reach the test voltage, the reactor and the test piece are tested in series, when the circuit is in a resonant state, the output voltage of the transformer Q times (Q is the circuit quality factor) can be generated on the test piece, and the power provided by the power supply is only the active power consumed in the circuit.

4. Cable and resonance parallel method, when the main test requirements of the test voltage transformer and current are met, the anti-parallel connection with the test parameters is used to meet the test requirements of the resonant circuit, and the capacitive current of the test reactor is compensated when the induced current is compensated.

Respondent: Huatian Power.

Performance characteristics of the complete set of frequency conversion series resonance test device:

Packaged systems. 1.The output voltage waveform is good, the loop is in the power frequency resonant state, and it has low reactance to the power frequency fundamental current, and high reactance to other harmonic currents, and has excellent filtering performance.

2.Small power capacity is required. Since the circuit is in a resonant state, the output capacity is Q times the required power supply capacity, and the figure of merit Q value can reach 20 80.

3.When the test sample breaks down and the loop is detuned, the reactor immediately plays a role in limiting the short-circuit current, and the loop current is only 1 q of the normal working current, which will not aggravate the damage to the tested product.

4.The device is a dry-type combined series resonance device, which is composed of a dry-type test transformer (excitation transformer) and a dry-type reactor.

5.The whole set of equipment of this device should be combined and suitable for on-site use.

6.The voltage regulation control box has the function of over-current protection, and the over-current protection adopts DIP setting.

7.The reactor used in this device should adopt the method of continuous adjustable air gap, which is convenient to adjust its inductance value in a wide range.

Series resonant booster equipment.

Reactors and excitation transformers.

1.The difference between the inductance value of the reactor and the rated inductance value shall not exceed -5% +3% of the rated inductance value.

2.The insulation level of the reactor can withstand the action of the working frequency voltage of its rated voltage, and will not cause flashover and breakdown.

3.Under the load and time corresponding to the working of the resonant device, the temperature rise of the winding is not more than 45K.

4.Under the rated voltage, the reactor will carry out two high-end short-circuit discharges to the ground within 5min, and the whole device will not be damaged.

5.The partial discharge test of the reactor is carried out under the device's own system, and is not more than 10pc under the rated voltage.

6.The operation performance of the inductance reactor is stable, sensitive, non-jamming, and can be continuously adjusted, and the air gap position indication has a corresponding relationship with the inductance value, and the indication position should be correct and reliable.

7.The connection of the reactor operating system is a soft connection with a certain adjustment range.

8.The ratio of the no-load loss of the reactor after the withstand voltage to the pre-withstand voltage value is not more than a time.

9.The DC resistance, conversion ratio, insulation resistance, and dielectric loss performance requirements of the excitation transformer meet the performance requirements.

10.The temperature rise performance of the dry-type excitation transformer meets the rated capacity conditions, and the temperature rise of the winding is not more than 45K, and the insulation is not cracked.

11.The insulation level of the excitation transformer should withstand the action of the rated output voltage at the working frequency for 5min, and no flashover and breakdown will occur.

Complete set of frequency conversion series resonance test device.

The complete set of variable frequency series resonance test device is composed of variable frequency power supply, excitation transformer, high-voltage reactor and capacitance voltage divider; The complete set of frequency conversion series resonance test device adopts the method of adjusting the frequency of the power supply, so that the reactor and the tested capacitor can achieve resonance, and obtain high voltage and high current on the tested product. The capacitance and reactor of the sample are connected in series resonance, the voltage divider is connected in parallel with the sample, and the resonant voltage is measured by the complete set of frequency conversion series resonance test device, and the overvoltage protection signal is issued; The excitation transformer couples the FM power output to a series resonant circuit to provide the excitation power of the series resonant.

The complete set of frequency conversion series resonance test device has a high degree of automation, small size and light weight. The weight of each unit of the complete set of equipment does not exceed 40kg, which is suitable for on-site handling. The reactor adopts dry epoxy casting, which is reliable in operation and easy to handle, and the on-site test does not need to be hoisted, and the installation test can be carried out manually.

Inverter series resonance test equipment is widely used in electric power, metallurgy, petroleum, chemical and other industries.

Functional characteristics of the complete set of frequency conversion series resonance test device:

1. High stability and reliability, the system adopts imported power components as the core of power conversion.

2. The automatic tuning function is powerful, and the frequency sweep curve is displayed between 30 Hz and 300 Hz when the frequency conversion series resonance test system is automatically tuned.

3. Support a variety of test modes, the system supports the test modes of "automatic tuning manual voltage regulation", "automatic tuning automatic voltage regulation" and "manual tuning manual voltage regulation".

4. The system has a friendly human-machine interface, test parameter setting, test control, and equivalent screen display of test results, which is intuitive and clear, and has the functions of automatic timing and operation prompts.

5. The protection function is perfect, and the complete set of frequency conversion series resonance test device has the functions of zero protection, overcurrent protection, overvoltage protection, flashover protection, etc., which ensures the reliability of the system.

Respondent: Huatian Power.