How power is measured: definition and types of loads, dependence on network parameters, ways to take into account kilowatts

According to the operation of the apartment electricity meter, it can be traced that the winding up of kilowatt-hours occurs the faster, the greater the load is supplied to the network. This is one of the ways in which power is measured. There are several varieties of the indicator, denoted by the first letter of the English watt - W. The amount of energy consumption depends on the parameters of the electrical circuit of the dwelling - it is directly proportional to the power of the connected pantographs.

Types of electrical power

The physical quantity W represents the rate of change, transmission, consumption and transformation of energy of the system under consideration. Specifically, the definition of power sounds like the ratio of the work performed in a certain period to the time interval of action: W = ΔA / Δ t, J / s = watt (W).

With regard to the electrical network, we are talking about the movement of charge under the influence of voltage: A = U. The potential between two points of the conductor is the indicator of the energy of motion of a single nucleon. The full work of the flow of the entire number of electrons is Ap = U * Q, where Q is the total number of charges in the network. In this case, the power formula takes the form W = U * Q / t, the expression Q / t - electric current (I), that is, W = U * I.

In energy, there are several terms W:

• Active (useful W) in watts - it is expressed in the complete conversion of one load to another. An example is a light bulb, when it burns, electricity is completely converted into heat and light.
• Reactive, Wр - accompanied by the appearance of induction, as a result of which part of the energy returns to the network, negatively affects the state of the circuit, disrupting the balance of current and voltage. Measured in volt-amperes reactive VAR.
• Full, W = Wа + Wр - denoted by VA or kVA, MVA.
• The power of semantic understanding: maximum - according to the composition of power equipment, connected - total for all consumers of the network, transformer - according to the energy of the available converters, installed - algebraically added the highest active power of devices, declared - determined by the contract between the consumer and the power supply organization. All of these types are measured in megawatts - MW.

It is necessary to dwell in more detail on the reactive component of the total power. Usually Wp is parasitic, harmful. Its concept is associated with starting currents, it is created in devices as a result of inductive and capacitive energy oscillations of the electromagnetic field. It is determined from the expression Wр = U * I * sinφ, where the sine of the angle is the phase shift between the voltage drop and the operating current in transformers, motors and capacitors.

The nature of the installed equipment predetermines the redundancy of Wр, when capacitive devices and the potential increases, or deficiency, if the mains inductance prevails (voltage decreases). Using the principle of the opposite action, devices have been developed that make it possible to compensate for the harmfulness of Wp and improve the quality and efficiency of energy supply.

Influence of network parameters on kilowatts

From the formula W = U * I, it can be seen that the power depends simultaneously on two characteristics of the power system - voltage and current. Their influence on the network parameters is parity. The process of generating electrical power can be described as follows:

• U is the work spent on moving 1 pendant;
• I is the number of charges flowing through the conductor in 1 second.

According to the calculated value of W, the consumed energy of the network is determined, multiplying the amount of power by the time it is spent. By changing one of the parameters W in the direction of decreasing or increasing, it is possible to save the energy of the system by constant level - to obtain high amperage at low voltage or high network potential at weak movement of pendants.

Converting devices designed to change parameters, called voltage or current transformers. They are installed at step-up or step-down electrical substations to transfer energy from a source to consumers over long distances.

Load measurement methods

You can find out the power of the device by referring to its instructions or passport, and if not, look at the nameplate attached to the case. If there is no manufacturer data, then other methods are available to determine the energy of the equipment. The main one is measure the load with a wattmeter (a device for recording electrical power).

According to their purpose, they are divided into 3 classes: direct current and low-frequency (LF), optical and high-impulse. The latter are referred to as the radio range and are divided into 2 types: included in the line break (passing power) and mounted at the end point of the route as an agreed (absorbed) load. By the method of communicating information to the operator, digital and analog devices are distinguished - indicating pointer and self-recording. Brief characteristics of some meters:

1. LF wattmeters are used in single- and three-phase power frequency networks. Varmeters - devices for determining reactive power belong to the same category. Analog meters are represented by the D5071, D8002, Ts301 models. Digital ones combine the possibilities of fixing not only the Wа component, but also Wр. The total value is displayed on the scoreboard and external devices - a printer or electronic information storage. Devices of this type are SCHV02, CP3010, MI2010A.
2. Wattmeters of the transmitted power of the radio range. Current and voltage transformers serve as sensors in the meter. For ultrahigh frequencies - thermistor, galvanomagnetic and thermoelectric converters. Samples - NAS, M2-32, M2-23.
3. Wattmeters for measuring the absorbed load of radio spectrum pulses - they use the power reflection coefficient. There are several types of devices: thermistor M3-28 and M3-22A, calorimetric MK3-68, MK3-70, M3-13, thermoelectric M3-93, M3-56, M3-51 wattmeters and with a peak detector M3-3A, M3-5A.
4. Optical meters - OM3-65, OMK3-69.

In addition to the help of special devices, the power is recognized by applying a calculation formula: an ammeter is included in the break of one of the supply wires, and the current and voltage of the network are determined. Multiplying the values ​​will give the desired result.