CN115833146A - Mobile single-phase motor compensation device - Google Patents

Abstract

The invention discloses a mobile single-phase motor compensation device, which relates to the technical field of circuit compensation devices and comprises a power socket, a power supply and a control circuit, wherein the power socket is connected to a power supply; the motor socket is connected to the power socket; a motor connected to the motor socket; the compensating device is connected in parallel with a lead connected with the power socket and the motor socket; the compensation device comprises a capacitance selector, a first capacitor and a second capacitor, wherein the first capacitor and the second capacitor are electrically connected with the capacitance selector; the method has the advantages of being convenient to use, capable of compensating or balancing inductive reactive power of the electrical equipment, capable of reducing power grid loss and the like.

Description

Mobile single-phase motor compensation device

Technical Field

The invention relates to the technical field of circuit compensation devices, in particular to a mobile single-phase motor compensation device.

Background

The power output by the power grid comprises two parts: firstly, active power; second, reactive power.

Directly consuming electric energy, converting the electric energy into mechanical energy, heat energy, chemical energy or sound energy, utilizing the energy to do work, and the part of power is called active power;

the method is characterized in that electric energy is not consumed, but converted into energy in another form, the energy is taken as a necessary condition that electric equipment can do work, the energy is periodically converted with the electric energy in a power grid, the part of power is called reactive power, for example, the electric energy occupied by an electromagnetic element (a motor) for establishing a magnetic field, and the electric energy occupied by an electric field is established by a capacitor;

the transmission of reactive power aggravates the load of the power grid, so that the loss of the power grid is increased, and the voltage of the system is reduced;

therefore, the movable single-phase motor compensation device is provided, and transmission of reactive power can be reduced.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a mobile single-phase motor compensation device, so as to solve the problems that the transmission of the reactive power of the motor in the prior art described in the background art aggravates the load of a power grid, increases the loss of the power grid and reduces the voltage of the system.

In order to solve the above problems, the present invention provides the following technical solutions: a mobile single-phase motor compensation device comprises

The power socket is connected to a power supply;

the motor socket is connected to the power socket;

a motor connected to the motor socket;

the compensating device is connected in parallel to a lead connected with the power socket and the motor socket;

the compensation device comprises a capacitance selector, a first capacitor and a second capacitor, wherein the first capacitor, the second capacitor and the capacitance selector are electrically connected.

The technical scheme has the advantages that:

the capacitor in the compensation device is directly connected with the motor in parallel, and is put into or out of service at the same time, so that reactive power can not flow backwards, the power factor of a user is ensured to be always in a lagging state, and the compensation device is beneficial to the user and a power grid;

the starting current of the motor is reduced, sparks of the contactor are reduced, the reliability of work of the control electric appliance is improved, and the service lives of the motor and the control equipment are prolonged.

Drawings

Fig. 1 is a schematic diagram of a mobile single-phase motor compensation apparatus of the present invention.

Fig. 2 is a circuit diagram of a mobile single-phase motor compensation device of the present invention.

Wherein: power socket 10, capacitance selector 20, first capacitance 30, second capacitance 40, motor socket 50, motor 60, power supply 70.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to fig. 1-2, in the first embodiment, a mobile single-phase motor compensation device comprises

A power socket 10 connected to a power source 70;

a motor socket 50 connected to the power socket 10;

a motor 60 connected to the motor socket 50;

a compensating device connected in parallel to a lead wire connecting the power socket 10 and the motor socket 50;

the compensation device comprises a capacitance selector 20, a first capacitor 30 and a second capacitor 40, wherein the first capacitor 30, the second capacitor 40 and the capacitance selector 20 are electrically connected.

The present embodiment is implemented as follows:

when the electric power socket is used, a plug of the motor socket 50 is connected with the power socket 10, a power supply 70 is connected, then the plug of the motor 60 is connected with the motor socket 50, and then the first capacitor 30 or the second capacitor 40 is selected through the capacitor selector 20;

when the power of the motor 60 is 1.5 kilowatts, the capacitance selector 20 is adjusted to switch on the compensation capacitance of the first capacitance 30 with a capacity of 48uf;

when the power of the motor 60 is 2.2 kilowatts, the capacitance selector 20 is adjusted to switch on the compensation capacitance of the second capacitance 40 with a capacity of 70uf; the capacitance selector 20 is used to adjust the capacitance, and is adjusted according to the power of the motor 60.

Compensation principle:

when the current does work in the inductance element, the current lags behind the voltage by 90 degrees; when the current does work in the capacitor element, the current leads the voltage by 90 degrees; in the same circuit, the directions of the inductive current and the capacitive current are opposite, and the difference is 180 degrees; the capacitor element is proportionally arranged in the electromagnetic element circuit, so that the currents of the capacitor element and the electromagnetic element are mutually offset, and the included angle between the current vector and the voltage vector can be reduced;

connecting the device with capacitive power load and inductive power load in parallel in the same circuit, and exchanging energy between the two loads; in this way, the reactive power required by the inductive load can be compensated by the reactive power output by the capacitive load.

Reactive power is compensated, and a proportional constant of active power in a power grid can be increased;

the design capacity of power generation and supply equipment is reduced, investment is reduced, and for example, when the power factor cos phi =0.8 is increased to cos phi =0.95, the equipment capacity can be saved by arranging a 1kvar capacitor by 0.52kW; on the contrary, for the original equipment, the capacity of power generation and supply equipment is increased by 0.52kW; therefore, for new construction and reconstruction projects, reactive compensation is fully considered, so that the design capacity can be reduced, and the investment is reduced;

reducing the line loss by the formula Δ Ρ% = (1-cos phi/cos phi) × 100%, where cos phi is the power factor before compensation, and cos phi is the power factor after compensation:

cos phi is larger than cos phi, so that the line loss rate is reduced after the power factor is improved, the design capacity is reduced, the investment is reduced, the transmission proportion of active power in a power grid is increased, and the reduction of the line loss directly determines and influences the economic benefit of power supply enterprises. Therefore, the power factor is an important index for assessing economic benefits, and planning and implementing reactive compensation are imperative.

The parallel capacitor can compensate or balance the inductive reactive power of the electrical equipment, when the capacitive reactive power QC is equal to the inductive reactive power QL, the power grid only transmits the active power P, according to the relevant regulations of the country, the power factor of a high-voltage user should reach more than 0.9, and the power factor of a low-voltage user should reach more than 0.85;

if the capacitor power is selected to be Qc, the power factor is:

cosφ= P/ (P2 + (QL-Qc)2)1/2

in the actual engineering, the power factor value required to be achieved after compensation is determined according to the load condition and the requirement of a power supply department, and then the installation capacity of the capacitor is calculated:

Qc = P(tanf1 - tanf2)=P〔(1/cos2f1-1)1/2-(1/cos2f2-1)1/2〕

in the formula:

mounting capacity of Qc-capacitor, kvar

Active power of P system, kW

tan phi 1- -power factor angle before compensation, cosf1- -power factor before compensation

tan phi 2- -compensated power factor angle, cosf2- -compensated power factor

In a large system, reactive compensation is also used for adjusting the voltage of the power grid and improving the stability of the power grid.

In small systems, three-phase unbalanced currents can also be regulated by appropriate reactive compensation methods. According to wangs theorem: an inductor or capacitor connected across the phases can transfer active current between the phases. Therefore, for a system with unbalanced three-phase current, as long as capacitors with different capacities are properly connected between each phase and a zero line, the power factor of each phase can be compensated to be close to 1, and the active current of each phase can reach a balanced state.

The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, many variations and modifications can be made without departing from the inventive concept of the present invention, which falls into the protection scope of the present invention.

Claims (1)

1. A mobile single-phase motor compensation device is characterized by comprising

The power socket is connected to a power supply;

it is characterized in that the preparation method is characterized in that,

the motor socket is connected to the power socket;

a motor connected to the motor socket;

the compensating device is connected in parallel to a lead connected with the power socket and the motor socket;

the compensation device comprises a capacitance selector, a first capacitor and a second capacitor, wherein the first capacitor, the second capacitor and the capacitance selector are electrically connected.

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