Remaining current monitoring device for safe use of electricity

AnkruiRemaining current monitoring device for safe use of electricity

Remaining current monitoring device for safe use of electricityProduct application background

With the development of electrical modernization, people's lives have changed, and more and more electrical equipment has begun to enter households. The normal operation of electrical equipment and people's personal safety are very important. In the process of electricity consumption in civil and industrial buildings, the safe operation of equipment and the personal safety of operators are also crucial. Therefore, it is not only necessary to monitor conventional electrical parameters such as voltage and current, but also to monitor leakage current. Leakage current is an abnormal current in electrical circuits, which refers to the phenomenon where some of the current in the circuit, after being emitted from the power source, does not follow the predetermined path through the corresponding load or component, but decisively flows to the ground wire or other non target routes. If not dealt with in a timely manner, leakage current may pose great harm to the human body and objects. Therefore, controlling the harm of leakage current is very important.

Causes and Control Methods of Electric Leakage

1. Aging or damage of insulation materials

After a period of time, insulation materials will undergo aging or damage due to long-term exposure to factors such as electric field pressure, current, and temperature, thereby shortening the service life of the device.

2. Line design issues

The design of electrical circuits can also lead to the formation of leakage current. For example, if there are open circuits, short circuits, and leakage problems inside the circuit, it will cause voltage to flow to the ground or other non predetermined paths, resulting in leakage current.

3. Poor device processing and manufacturing

In the manufacturing process of electronic devices, problems such as tin hanging, poor soldering, and incomplete silver paste printing can also cause local current flow in the circuit to be abnormal, resulting in leakage current.

4. Incorrect use of electricity

During the use of electrical appliances, accidental operation may result in leakage current. For example, poor contact of socket plugs, incorrect wiring methods, etc. Poor grounding when using electrical appliances can also lead to phenomena such as leakage current and induced current.

Solution

A: Correct use of grounding wire:

When using electrical appliances, it is advisable to use appliances with grounding wires as much as possible, and ground all points such as the appliance casing to avoid charge accumulation and accidental leakage.

B: Equipment maintenance:

After a certain period of use, electronic devices should be inspected and maintained in a timely manner. If any damage or aging is found, it should be repaired or replaced in a timely manner to avoid affecting the normal operation of electronic devices.

Leakage current monitoring method and zero sequence current monitoring method

Leakage current (residual current)

The specific method is to install one CT on each of the tested three-phase line and the N line, or to pass the three-phase wire and the N line through a residual current CT, to obtain the current vector sum of the three-phase wire and the neutral line N, IA *+IB *+IC *+IN *. When no single-phase grounding fault occurs, regardless of whether the three-phase load is balanced or not, this vector sum is zero; When a phase to ground fault occurs, the fault current will return to the power supply through the protective PE and metal components connected to the ground, that is, IA *+IB *+IC *+IN *, and the value at this time is the ground fault current Id.

The function of residual current operated relay

1、 Protection against direct contact electric shock accidents

In the protection against direct contact electric shock accidents, residual current relays (RCDs) are only used as supplementary protection measures to the basic protection measures for direct contact electric shock accidents (excluding protection against direct contact electric shock accidents between phases and N lines).

When used for direct contact electric shock accident protection, RCD without delay should be selected, with a rated operating current not exceeding 30mA.

2、 Protection against indirect contact electric shock accidents

The main measure for protecting against indirect contact electric shock accidents is to adopt an automatic power-off protection method to prevent harmful effects or equipment damage accidents caused by continuous dangerous voltage on the exposed conductors of electrical equipment due to insulation damage. When insulation damage occurs in the circuit and the grounding fault current value is less than the operating current value of the overcurrent protection device, RCD should be installed.

Summary: It can greatly reduce electricity accidents and ensure the safety of people's lives and property.

Direct contact electric shock: Direct contact electric shock refers to the electric shock that occurs when the charged body of the equipment and circuit is in normal operation (such as the electric shock caused by accidental contact with the wiring terminal), also known as electric shock under normal conditions.

Indirect contact electric shock: Indirect contact electric shock is an electric shock that occurs when a conductor that is not charged under normal conditions is accidentally charged when the equipment or circuit fails (such as an electric shock that occurs when it touches the shell of a leakage device), also known as an electric shock in a fault state. The human body is subjected to lower than normal working voltage, such as human body voltage<phase voltage 220V, contact with charged shells, etc. Its danger is also relatively high.

Instructions for indirect contact electric shock protection

Application places and positions of ASJ series residual current operated relays

1、 End protection

The following equipment and locations should be equipped with end protection residual current relays:

1) Category I mobile electrical equipment and handheld power tools;

2) Electrical equipment for industrial production;

3) Electrical machinery and equipment at construction sites;

4) Electrical equipment installed outdoors;

5) Electrical equipment for temporary use of electricity;

6) Other power sockets or socket circuits for institutions, schools, hotels, restaurants, enterprises, institutions, and residential buildings, except for wall mounted air conditioning power sockets;

7) Electrical equipment for swimming pools, fountain pools, bathrooms, and bathhouses;

8) Power supply lines and equipment installed in water;

9) Medical electrical equipment that may come into direct contact with the human body in hospitals;

10) Electrical equipment for agricultural production;

11) Electricity consumption for aquatic product processing;

12) Other locations where RCD installation is required.

2、 Line protection

When using secondary or tertiary protection for low-voltage distribution lines according to specific situations, RCD should be installed at the power supply end, load group head end, or line end (power distribution box of agricultural production equipment).

ASJ series residual current operated relays in different distribution systems

Selection of ASJ series residual current operated relay products

Explanation: AC type: RCD (sinusoidal alternating current) that can ensure tripping for sudden or slowly rising residual sinusoidal alternating current

Type A: RCD (sinusoidal AC&pulsed DC) that can ensure tripping for sudden or slowly rising residual sinusoidal AC current and 6mA residual pulsating DC current

F-type residual current relay: Same as A-type, single-phase circuit composite residual current, residual pulsating DC current below 10mA

B-type residual current relay: Same as F-type, 1kHz sine, smooth DC superimposed residual AC current, residual pulsating DC, single-phase multiphase residual pulsating rectified DC

Product selection of AKH-0.66 L series residual current transformer

ASJ residual current action relay wiring and selection instructions

Typical Design of ASJ Series Residual Current Operated Relays

The feeder cabinet in the desulfurization power cabinet is designed with ASJ10-LD1A residual current action relay. When the residual current in the circuit exceeds the set value, the circuit trips.

Typical Design of ASJ Series Residual Current Operated Relays

The feeding circuit of the low-voltage distribution cabinet in the coal washing plant is equipped with a leakage relay, which is installed on the drawer panel,

After the leakage relay alarm, the signal enters the intelligent dry selection PLC

Installation Example of ASJ Series Products

Typical Cases of ASJ Series Products

AIM-R100 product application background

In the TN-S grounding system of medical Class 1 and Class 2 places such as delivery rooms, hemodialysis centers, and emergency rooms in hospitals, it is necessary to monitor leakage current. There are many monitoring circuits, high accuracy requirements, and an over limit alarm function.

In low-voltage distribution systems in laboratories, testing centers, and other places, it is necessary to monitor leakage current. There are many circuits with high accuracy requirements, and an over limit alarm function is required.

In low-voltage distribution systems such as biopharmaceuticals and precision instruments, it is necessary to monitor electrical leakage with high precision requirements.

Application of AIM-R100 Residual Current Monitor in Hospital Settings

12 residual current monitoring channels, 0mA~5000mA, with one alarm relay output

Application background of ASJ60 series residual current monitoring products

The ASJ60-LD16A residual current monitoring device is suitable for use in distribution lines with an AC rated voltage of 400V and below, and is used to monitor the residual current in the line as a residual current fire monitoring device. It can be combined with low-voltage circuit breakers and low-voltage AC contactors to form a residual current protection device, which is used to provide grounding fault protection for electrical circuits, prevent equipment damage and electrical fire accidents caused by grounding fault currents, or provide indirect contact protection for personal electric shock hazards.

This product can be used in distribution boxes for places such as petrochemicals, industrial plants, large public buildings, kindergartens, nursing homes, etc. It can also be used in distribution boxes for street lights, courtyard lights, and landscape lights to monitor leakage or grounding faults.

ASJ60 series multi-channel residual current monitoring products

16 residual current monitoring channels, 1mA~30A, 16 independent relay outputs

ASJ60 series single channel residual current monitoring product

1 residual current monitoring, 1mA~30A, 1 water immersion monitoring, insulation monitoring, 2 outputs, HPLC communication

Street Lamp Safety Electricity Management Cloud Platform

Install a single residual current monitoring product at the street lamp location to monitor the residual current of the street lamp power supply circuit. When there is a leakage problem in the street lamp power supply, an alarm will be triggered in a timely manner to prompt the staff to investigate. At the same time, the product can perform offline insulation monitoring to check whether there is a problem with the street lamp insulation.

Multiple residual current monitoring products are installed at the street lamp control box to monitor the residual current of the overall power supply circuit. When an abnormality occurs in the circuit, the product sends an alarm signal and can be disconnected according to the actual situation.

All monitoring devices can remotely send data to the monitoring platform through communication. The platform monitors all street lights in the entire area, and when a street light malfunctions, it promptly alarms and prompts staff to troubleshoot

Smart Street Lamp Control and Management Cloud Platform

Full Area View

Electrical parameter monitoring

Leakage current monitoring

electricity metering

Insulation monitoring

time-sharing control

Light quantity control

Intelligent group control

Dying Gasp

abnormal alarm

Offline alarm

statistical analysis

Operations Management

expert report