Basic knowledge of complete installation wiring - schematic diagram of secondary wiring

Basic knowledge of complete installation wiring - schematic diagram of secondary wiring

The schematic diagram of the secondary wiring is used to indicate the working principle of the relay protection measuring instrument and the automatic device.
Usually the secondary wiring and the primary wiring are related to the secondary wiring. On the schematic, all instruments, relays, and other electrical appliances are represented in a holistic manner. The interconnected current loops, voltage loops, and DC loops are all integrated and represent the portion of the primary loop involved. The feature of this wiring diagram is that it allows the viewer to have a clear overall concept of the composition and operation of the entire device. It is the basis for drawing the development diagram and installing the wiring diagram. An open drawing is a drawing drawn from a schematic. The general situation of the unfolding diagram: on the one hand, the position of the current and voltage transformer connected to the protection and measuring device in the first system diagram; on the other hand, the development of the protection control circuit. The expansion map can be divided into two parts: AC and DC. The AC circuit expansion diagram generally refers to the wiring diagram of the AC current loop and the AC voltage loop. The DC circuit expansion diagram refers to the wiring diagram of the control loop, protection loop, and signal loop.

Installation wiring diagram generally includes screen (table, box) surface layout, screen (table, box) rear view layout, rear wiring diagram and terminal arrangement diagram, which is the main drawing of manufacturing and installation, and also the main reference drawing for operation and maintenance. . The installation wiring diagram is generally drawn by the manufacturer according to the corresponding position of the components arranged on the development drawing, front and back, and is used for guiding the production inspection. At the same time, the order unit is provided with the product, which is the main reference drawing for the installation and commissioning operation. . The terminal arrangement diagram is the wiring diagram of the secondary cable on the screen, which is mainly used by the construction unit, and is also the main reference diagram for debugging and maintenance.
The floor plan is a drawing showing the layout of various electrical equipment and lines. It is an important basis for electrical installation. It is a drawing that must be referenced by our complete electrical equipment factory. It shows the plane position, installation method and various aspects of various electrical equipment. The drawings of the relationship, so that the manufacturer must consider the way of entering and exiting the line and the cabinet production in the production process. (ie whether there is a back door mounted cabinet) In the daily work production, each production personnel should know the name, model, symbol, function and structure of the electrical components, and also understand the principles, such as voltage transformers, current transformers. The voltage transformer changes the high voltage to a standard low voltage (100V). The current transformer changes the high voltage current or the low voltage and large current into a standard low voltage and small current (5A, 1A). For the meter, measure the voltage, current, and electric energy of the system and cooperate with the relay to protect the system and equipment from overvoltage, overcurrent, single-phase grounding, etc., so that the secondary circuit is isolated from the primary circuit. The secondary circuit operates safely. At the same time, the transformer becomes a standard low voltage and low current, which makes the voltage level and current level of electrical measuring instruments and relays have a unified standard. The voltage transformer is equivalent to a voltage source and is basically in an open circuit operation. The connected loads are loads with large resistance values, such as voltmeters, coils of voltage relays, and so on. These load components are connected in parallel, so they cannot be short-circuited, otherwise the transformer will be burnt out, so the secondary side of the voltage transformer is not allowed to be short-circuited and the fuse should be installed (except the metering circuit). The current transformer is equivalent to a current source, and the load resistance is very small, such as ammeter, current relay, etc. These components are connected in series, so the secondary side of the current transformer can not be opened, otherwise high voltage will be generated, the transformer The secondary side does not install components such as fuses and switches. When switching is required, short-circuit should be taken. Pay attention to the polarity of the transformer in the installation wiring. Relays: Relays are currently available in China for a wide variety of applications, including control relays and protection relays, for protection devices called protection relays; for control control relays. Relays are divided into metric relays and with or without relays depending on hole punching machine the function: 1. Measure relays are relays that measure the magnitude (or pressure, etc.) and operate in comparison to a predetermined value. Voltage relay: A relay that operates when the voltage in the circuit exceeds or falls below the set value; the power direction relay: a relay that operates when the current flows in a certain direction exceeds the set value; the impedance relay: the distance from the reaction fault point to the installation location of the protection device Impedance, and relay that determines the action time according to the distance (impedance); differential relay: a relay that operates at different points in the circuit and exceeds the set value. 2. With or without relay: The relay with or without relay is a relay that acts after the action of measuring the relay action, acts on the switch trip delay, signal, etc., or it is a kind of power-on (power) The relay does not have the function of measuring circuit parameters. Such as time relay: a relay that closes or opens its contacts after a certain delay except for the signal; an intermediate relay: a relay used to increase the number of signals or amplify the signal; a signal relay: used to signal or act on the signal system The relay shown.
In the control auxiliary circuit, in addition to the relay, the protection circuit is indispensable for the control switch. Its function is mainly used to turn on and off the main switch, such as control buttons, switches, universal switches LW5, LW12, etc. In addition to the above control protection components, there are electricians. Meters, indicating instruments, recording instruments, integrated meters, and frequency meters are also required for generators.