CN204405734U - A kind of electric energy meter with residual current detection function - Google Patents

Abstract

The utility model discloses an electric energy meter with a residual current detection function, which comprises a processor, a nonvolatile memory, a metering unit, a human-computer interaction unit, and a communication interface; the processor and the nonvolatile memory, The metering unit, the human-computer interaction unit, and the communication interface are connected; it is characterized in that the electric energy meter also includes a residual current transformer interface, an analog-to-digital conversion unit, a relay and a circuit breaker interface; the residual current transformer interface passes through the analog-to-digital conversion unit It is connected with the processor; the circuit breaker interface is connected with the processor through a relay. The electric energy meter of the utility model can effectively detect the residual current of the terminal user, provide accurate grounding fault detection, control and reduce line loss, and prevent equipment accidents and electrical fires caused thereby.

Description

An Electric Energy Meter with Residual Current Detection Function

technical field

The utility model relates to an electric energy meter with a residual current detection function.

Background technique

As an electric energy metering device, the electric energy meter is widely used in various aspects of the national economy and people's livelihood. Installing a residual current operated protective device (referred to as RCD, hereinafter referred to as a residual current protector) in a low-voltage power grid is an effective protective measure to prevent personal electric shock, electrical fire and electrical equipment damage. Countries around the world and the International Electrotechnical Commission have vigorously promoted the use of residual current-operated protectors in low-voltage power grids by formulating corresponding electrical installation regulations and electricity utilization regulations.

The basic principle is that the iron core surrounds all the current-carrying conductors of an electrical circuit, and the magnetic flux generated in the magnetic core is related to the arithmetic sum of the currents of these conductors at an instant; the current flowing in one direction is assumed to be positive ( I1), then the current flowing in the opposite direction is negative (I2). In a normal circuit without faults I1 + I2 = 0, there is no magnetic flux in the core and the electromotive force in the coil is zero. The ground fault current Id flows to the fault point through the magnetic core, but returns to the power supply through the earth or the protection line of the TN system. The currents through the conductors of the core are thus no longer balanced, and the difference in currents creates a magnetic flux within the core. This current is called the "residual" current, and this principle is also known as the "residual current" principle.

As a terminal device for electricity consumption, the energy meter has a residual current protection function while measuring electrical parameters and measuring electrical energy, which can provide accurate ground fault detection, control and reduce line loss, and prevent equipment accidents and electrical fires caused by it. It can be used as an electrical fire monitor, and at the same time has the function of preventing electric shock and ensuring personal safety. Residual current protection needs to be equipped with a special current residual current transformer. According to the comparison of the sampled residual current value and the set residual current action value, it is judged whether to start the residual current protection function.

In order to adapt to different requirements, the residual current is used as an over-limit task. When the residual current value is greater than the fixed value, the relay acts or sends out an alarm. At the same time, you can choose its function switching, residual current threshold and alarm mode through setting.

Contents of the invention

The problem to be solved by the utility model is to enable the electric energy meter to have a residual current protection function while measuring electric parameters and measuring electric energy.

For solving the problems referred to above, the scheme that the utility model adopts is as follows:

An electric energy meter with a residual current detection function, including a processor, a nonvolatile memory, a metering unit, a human-computer interaction unit, and a communication interface; the processor and the nonvolatile memory, the metering unit, and the man-machine The interaction unit is connected to the communication interface; it is characterized in that the electric energy meter also includes a residual current transformer interface, an analog-to-digital conversion unit, a relay and a circuit breaker interface; the residual current transformer interface communicates with the processor through the analog-to-digital conversion unit connected; the circuit breaker interface is connected to the processor through a relay. Among them, the non-volatile memory is ferroelectric memory; the metering unit is an integrated circuit chip with the function of measuring current and voltage and calculating the electric energy value; the human-computer interaction unit is composed of LCD display screen, LED indicator light and keys; the communication interface is RS485 interface.

Further, it also includes a residual current transformer and a circuit breaker, the residual current transformer is connected to the processor via the analog-to-digital conversion unit through the residual current transformer interface; the circuit breaker is connected to the processor through the circuit breaker interface Connected to the processor via the relay.

The technical effect of the utility model is as follows:

1. The energy meter of the utility model can effectively detect the residual current of the end user, provide accurate ground fault detection, control and reduce line loss, and prevent equipment accidents and electrical fires caused by it.

2. The electric energy meter of the utility model can provide various alarm and control means to protect the residual current.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail.

As shown in Figure 1, an electric energy meter with a residual current detection function includes a processor 10, a voltage and current collector 21, a metering chip 22, a residual current transformer 31, a residual current transformer interface 32, and an analog-to-digital converter 33 , a relay 34 , a circuit breaker interface 35 , a circuit breaker 36 , a non-volatile memory 40 , a human-computer interaction unit 50 and a communication interface 60 . The processor 10 is connected with the non-volatile memory 40 , the human-computer interaction unit 50 and the communication interface 60 . The voltage and current collector 21 and the metering chip 22 form a metering unit. The voltage and current collector 21 is used to collect voltage and current, and the collected data is analog. The metering chip 22 is an integrated circuit chip, which is used to convert the analog quantities of voltage and current collected by the voltage and current collector 21 into digital quantities and then calculate the electric energy value. The voltage and current collector 21 is connected to the processor 10 through the metering chip 22 , so that the processor 10 can obtain data such as voltage value, current value and electric energy value through the metering chip 22 . The residual current transformer 31 is connected to the processor 10 through the residual current transformer interface 32 and the analog-to-digital conversion unit 33 . The residual current transformer 31 is used to detect residual current, and the detected residual current is sent to the analog-to-digital conversion unit 33 through the residual current transformer interface 32 in an analog manner. The analog-to-digital conversion unit 33 is used to convert the analog residual current into a digital value and send it to the processor 10 . The processor 10 is connected to a circuit breaker 36 through a relay 34 and a circuit breaker interface 35 . The relay 34 is used to generate a control signal for opening the circuit breaker 36 , and the opening control signal generated by the relay 34 is transmitted to the circuit breaker 36 through the circuit breaker interface 35 . Non-volatile memory 40 is employed for storing historical voltage, current and energy data and configuration parameters. In this embodiment, the nonvolatile memory 40 is a ferroelectric memory. The human-computer interaction unit 50 is composed of an LCD display, LED indicator lights and keys, and is used for human-computer interaction. The communication interface 60 adopts RS485 interface for uploading data and issuing instructions and configuration data. The voltage and current collector 21, the residual current transformer 31 and the circuit breaker 36 are all connected to the detected and controlled AC line. Wherein, the residual current transformer 31 is close to the user side and connected to the user equipment 99 . The circuit breaker 36 is located on the upstream side. The voltage and current collector 21 is located between the residual current transformer 31 and the circuit breaker 36 . The AC line to be detected and controlled is three-phase AC.

The energy meter of this embodiment can set the alarm threshold and alarm mode of the residual current through the human-computer interaction unit 50, or set the alarm threshold and alarm mode of the residual current by the background server and issue it through the RS485 communication interface 60 to the energy meter. Parameter values such as the alarm threshold and alarm mode of the residual current are set and stored in the non-volatile memory 40 of the electric energy meter. When the electric energy meter in this embodiment is installed on the line, the residual current is sampled by the residual current transformer 31 , and the sampled value is converted by the analog-to-digital conversion unit 33 and provided to the processor 10 for judgment. The processor 10 judges whether the residual current exceeds the limit according to the alarm threshold value of the residual current stored in the non-volatile memory 40. If the residual current exceeds the alarm threshold value of the residual current, the processor 10 sends a signal to the circuit breaker 36 through the relay 34. The circuit breaker 36 shuts down the circuit according to the control command for shutting down the circuit.

It should be noted that the electric energy meter in the above embodiment is an electric energy meter installed on three-phase alternating current. Those skilled in the art understand that the electric energy meter of the present invention can also be an electric energy meter for single-phase alternating current. In the above embodiments, the non-volatile memory 40 is a ferroelectric memory. Those skilled in the art understand that the non-volatile memory 40 may also use other memories such as EEPROM. In addition, in the electric energy meter of the above-mentioned embodiment, the residual current transformer 31 and the circuit breaker 36 are built-in, that is, the residual current transformer 31 and the circuit breaker 36 are installed in the electric energy meter as components. The built-in residual current transformer 31 and circuit breaker 36 are connected to the processor 10 through corresponding interfaces (ie, residual current transformer interface 32 and circuit breaker interface 35 ), so that the residual current transformer 31 and circuit breaker 36 are easily disassembled for maintenance. Those skilled in the art can understand that the residual current transformer 31 and the circuit breaker 36 can also be external. When the residual current transformer 31 and the circuit breaker 36 are external, the electric energy meter does not include the residual current transformer 31 and the circuit breaker. 36. The external residual current transformer 31 and circuit breaker 36 are connected to the electric energy meter through their corresponding interfaces (ie residual current transformer interface 32 and circuit breaker interface 35).

Claims (6)

1. the electric energy meter with residual current detection function, comprises processor, nonvolatile memory, metering units, man-machine interaction unit, communication interface; Described processor is connected with described nonvolatile memory, metering units, man-machine interaction unit, communication interface; It is characterized in that, this electric energy meter also comprises residual current transformer interface, AD conversion unit, relay and circuit breaker interface; Described residual current transformer interface is connected with described processor by AD conversion unit; Described circuit breaker interface is connected with described processor by relay.

2. the electric energy meter of band residual current detection function as claimed in claim 1, it is characterized in that, this electric energy meter also comprises residual current transformer and isolating switch, and described residual current transformer is connected with described processor through described AD conversion unit by described residual current transformer interface; Described isolating switch is connected with described processor through described relay by described circuit breaker interface.

3. the electric energy meter of band residual current detection function as claimed in claim 1 or 2, it is characterized in that, described nonvolatile memory is ferroelectric memory or EEPROM.

4. the electric energy meter of band residual current detection function as claimed in claim 1 or 2, it is characterized in that, described metering units comprises computation chip and electric current and voltage collector; Described computation chip is the integrated circuit (IC) chip having electric current and voltage measurement and calculate energy value function.

5. the electric energy meter of band residual current detection function as claimed in claim 1 or 2, it is characterized in that, described man-machine interaction unit is made up of LCD display, LED light and button.

6. the electric energy meter of band residual current detection function as claimed in claim 1 or 2, it is characterized in that, described communication interface is RS485 interface.