With the development of society, capacitor reactive power compensation frequency conversion technology, 9 medium frequency furnace, large AC/DC conversion equipment, seasonal energy lamps and other uv transient peak transients are only sinusoidal when the voltage and current suddenly rise. A transient distortion of the current and voltage in the circuit, its main manifestations are surge harmonics, intermittent waves.
At present, most of the power equipment manufacturing enterprises in China use ferromagnetic materials as the core part of motors, transformer ballasts and relays. The hysteresis of transient load in ferromagnetic materials produces iron loss and copper loss. These losses are in the equipment. The total energy consumption usually accounts for about 15% to 25% of P-active power; Q-reactive power.
New technologies and new equipment are constantly appearing. These devices send transients and harmonic waves into and pollute the power grid through capacitive coupling and inductive sensing. Prof. Chen Shousun of Tsinghua University proposed the concept of “distortion power†to solve the above problems. , and proposed to calculate the formula S2 = P2 + pan + D2; Q is a reactive power caused by voltage and current interactions with different phases of the same frequency; D is the "distortion power", a kind of transient current and harmonic generation Power.
1 Influence of Transient Load on Equipment Energy Consumption As the hysteresis of the ferromagnetic material obstructs the working magnetic field from penetrating the iron core of the material, alternating currents in the direction of instantaneous flow result in the generation of ferromagnetic eddy currents and copper losses in the electrical equipment. In an environment where transient currents vary in frequency, power consumption can be increased by 5% in electricity-consuming equipment, and power consumption can be increased by 2% (or more) in environments where instantaneous flow changes are very active.
The change is only active when the power demand remains constant, and the percentage of normal power loss is left 0.0083% of the power loss per instantaneous current. In the actual power use, most transients contain intermediate frequency frequencies. Let the power loss be r: Guardian LC2 Because the impedance of the power equipment is designed based on the minimum resistance loss, R is usually very small and can generally be ignored in the actual calculation, so its power loss approximate formula is: Suddenly interrupted. In a single-phase power system, when the voltage or current crosses zero, the transient does not generally occur. However, the instantaneous current in the three-phase power system appears almost without exception on two phases. The main reason is that the voltage and current are separated by 120. It is impossible for two phases to be zero at the same time. The transient surge voltage typical in a three-phase system is shown in Table 1: Table 1 Typical Instantaneous Surge Voltage Values ​​in Three-Phase Systems Phase vs. Sine Wave Phase/(Voltage Standard) Value 2 Conversion of electrical energy and field energy during current transients Since the magnetic energy Wm of an inductive device is abruptly interrupted, it must be interchanged (oscillated) with the alternating electrostatic energy Wc present in the alternate device. The energy behaves as: line voltage (maximum) Due to the resonance phenomenon, the inductive energy and the electrostatic energy must be exchanged in equal amounts, so that the oscillation of the Wm inductive energy and the electrostatic charge is exchanged until it completely disappears in the line resistance R. If The power loss of the core of a public power equipment is shown in the hysteresis curve of the power equipment with iron core. Rc is the copper loss caused by resistance and skin effect, and Rh is The magnetic loss caused by the Moore effect.Rm is the eddy current loss caused by the current flowing through the core. This loss is used in the total energy loss WT. Il is the average current, then EIl=Wl is the wattage lost per hour of transient load. Using this formula and the various values ​​mentioned above, according to the relevant determination, the ferromagnetic loss parameter of the transient power to the power equipment is obtained, and the energy loss expression in formula (7) is as follows: ab1 - 1 transient magnetic induction Intensity; - a system of main magnetic flux change; - a main magnetic field change time; - a transient load magnetic field change time; - magnetic field change cycle, in the 50Hz power supply system is 0.02s; - a instantaneous flow occurs every second 3 Elimination of instantaneous flow device input Meter reading record Time of reading meter days Number of anaphoric energy meter Digital daily average word Number 4 Elimination of power loss caused by transient power Based on the above loss analysis, it can be clearly seen that the transient power is in the power equipment. Is a typical useless work, its presence in addition to causing the device temperature to rise, but also cause distortion of the voltage waveform, affect the normal operation of the device, shorten the life of the device in the running power In preparation, the higher the frequency of transients, the greater the loss of electrical equipment caused by transient currents. Through comparative studies, we determined that reducing the power consumption of electrical equipment to save energy is actually to eliminate the system using hardware equipment. Transient power is currently used as a method of eliminating the hardware of the instantaneous current device in parallel with the power supply end of the power-consuming equipment, and grounding the transient current in the power grid into the earth through the grounding device of the hardware device to reduce the transient power in the device core and coils. In the mid-20th century, the advanced countries in the Western countries invested a lot of funds to develop and research the power equipment for suppressing the transient power of the power system, and developed a variety of electronic devices that suppress the instantaneous flow of the power system. , And formed a variety of series, and achieved significant power-saving effect 5 Statistical analysis of the effect of energy conservation In order to verify the power-saving situation of the power equipment installed to eliminate the transient current device, we chose to install in a workshop of a steel group company. Eliminating transient current devices for experimentation, and taking measures to ensure that production does not fluctuate greatly during the experiment, maintaining a comparative environment 2 Elimination of instantaneous flow devices before meter input Meter reading time period Days of days Electricity meter Digital daily average word Number identity, and the experimental records are listed in Table 2 Table 3 Statistical analysis available, no installation to eliminate the instantaneous flow device The average daily average number of characters was 4.66 when the output was unchanged, and the total number of meter reading days after the installation of the elimination of the transient current device was 127 days. The total number of words traveled on the meter was 475.4; the average daily number of words was 3.74, and the installation eliminated the transient current device. After the saving rate was 19.74%, the power saving effect was very obvious.
6 conclusions In view of the above analysis of transient power, the transient power has a great influence on the power consumption of the power equipment, and the effect of saving energy after adopting the elimination of transient load measures is very obvious. Therefore, it is eliminated in the case of severe shortage of power resources in China. The social benefits of saving electricity by transient power are very obvious, and should be promoted to the whole society under the guidance of the government.
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