CN205679686U - The external chopper of electric energy meter - Google Patents

Abstract

The utility model discloses an external circuit breaker for an electric energy meter, which comprises an electric operating mechanism part, a circuit breaker part and a current transformer; the current transformer is installed on the outgoing line of the electric energy meter and the output end is connected with a controller of the electric operating mechanism part The current transformer is used to detect the outlet current of the electric energy meter and transmit the detected current signal to the controller of the electric operating mechanism part; the controller of the electric operating mechanism part judges whether the outgoing line of the electric energy meter generates leakage current according to the detected current signal, and When the generated leakage current is greater than the set value, the circuit breaker is controlled to partially disconnect the outgoing line of the electric energy meter to ensure the safety of low-voltage power users. The utility model detects the leakage current through the current transformer, and cuts off the power supply in time according to the size of the leakage current, so that the user's electric energy can be disconnected in time when the leakage or a grounding fault occurs, and the leakage protection function is realized to protect the personal and property safety of the electricity user; In addition, the utility model has the advantages of simple realization, low cost and high reliability.

Description

Electric energy meter external circuit breaker

technical field

The utility model specifically relates to an external circuit breaker for an electric energy meter.

Background technique

With the rapid development of China's industry, people's living standards continue to improve, and various types of electrical equipment continue to increase, and there are many types, and the power consumption is also increasing. Safe use of electricity has become a necessary requirement in people's production and life, so higher requirements are placed on the stability and reliability of low-voltage switches.

The installation of leakage protectors in low-voltage power distribution systems is one of the effective measures to prevent personal electric shock accidents, and it is also a technical measure to prevent electrical fires and electrical equipment damage accidents caused by leakage. The leakage protector is a protective device used to prevent personal electric shock and electrical fire when the circuit or electrical insulation is damaged and short-circuited to the ground. It is generally installed on the branch circuit such as the socket of the distribution box of each household and the main line at the rear end of the meter outlet; Among them, the leakage protector installed on the main line at the back end of the meter outlet plays the role of general protection of the low-voltage power grid or leakage, grounding or insulation monitoring and protection of the main line. Therefore, the leakage protection plays a pivotal role in low-voltage switching appliances, and it has also attracted more and more attention.

However, a large number of cost-controlled smart meters currently on the market use external cost-controlled load switches to control power on and off. and the circuit breaker part, the outlet end of the fee-controlled smart meter goes out through the circuit breaker part of the external circuit breaker of the electric energy meter and connects to the low-voltage power user, and the electric operating mechanism part of the external circuit breaker of the electric energy meter is connected with the fee smart meter to obtain the fee Smart meter control signal: When the meter user owes the fee, the fee-controlled smart meter sends an opening signal, and the controller of the electric operating mechanism part controls the circuit breaker to trip and disconnect after receiving the opening signal from the fee-controlled smart meter. The power supply of low-voltage power users realizes the function of power outage due to meter arrears; when the user pays the fee, the fee-controlled smart meter sends a closing signal, and the controller of the electric operating mechanism receives the closing signal from the fee-controlled smart meter. Control the partial closure of the circuit breaker, connect the power supply of low-voltage power users, and realize the function of meter payment and power transmission.

However, at present, this kind of external circuit breaker of the electric energy meter only has the simple function of a circuit breaker; and as a main line load switch at the back end of the electric energy meter, if the branch line does not have any protective measures or protection functions, once personal electric shock or leakage occurs, the existing The external circuit breaker of the electric energy meter cannot apply any protective action, which will bring great personal and property threats to users, and may lead to personal safety accidents and property losses.

Utility model content

The purpose of the utility model is to provide an external circuit breaker for an electric energy meter with an electric leakage protection function, which is simple to implement and low in cost.

The electric energy meter external circuit breaker provided by the utility model includes an electric operating mechanism part and a circuit breaker part, and is characterized in that it also includes a current transformer; the current transformer is installed on the outgoing line of the electric energy meter, and the output terminal of the current transformer Connect with the controller of the electric operating mechanism; the current transformer is used to detect the outgoing current of the electric energy meter, and transmit the detected current signal to the controller of the electric operating mechanism; the controller of the electric operating mechanism detects The detected current judges whether there is a leakage current in the outgoing line of the electric energy meter, and sends a control command to control the circuit breaker to partially disconnect the outgoing line of the electric energy meter when the generated leakage current is greater than the set value, so as to ensure the electricity safety of low-voltage power users.

The electric energy meter is a single-phase electric energy meter or a three-phase electric energy meter.

When the watt-hour meter is a single-phase watt-hour meter, there are two current transformers, namely a live wire current transformer and a neutral wire current transformer; It is used to detect the live wire current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; the neutral wire in the outgoing line of the electric energy meter passes through the neutral wire current transformer, and the neutral wire current transformer is used to detect the neutral wire at the outlet end of the electric energy meter The current and the detection signal are transmitted to the controller of the electric operating mechanism.

The live wire current transformer and the neutral wire current transformer can be installed at the incoming line end of the circuit breaker part, or at the outgoing line end of the circuit breaker part at the same time.

When the electric energy meter is a three-phase electric energy meter, there are four current transformers, which are respectively A-phase current transformer, B-phase current transformer, C-phase current transformer and N-phase current transformer; The A-phase power line of the electric energy meter passes through the A-phase current transformer, and the A-phase current transformer is used to detect the A-phase current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; the B-phase power line in the electric energy meter outgoing line Through the B-phase current transformer, the B-phase current transformer is used to detect the B-phase current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; the C-phase power line in the electric energy meter outlet line passes through the C-phase current Transformer, C-phase current transformer is used to detect the C-phase current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; the N-phase power line in the electric energy meter outgoing line passes through the N-phase current transformer, and the N-phase The current transformer is used to detect the N-phase current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism.

The A-phase current transformers, B-phase current transformers, C-phase current transformers and N-phase current transformers can all be installed on the incoming line end of the circuit breaker part at the same time, or all can be installed on the outgoing line of the circuit breaker part at the same time end.

There is only one current transformer, and it is a residual current transformer; all outgoing lines of the electric energy meter pass through the residual current transformer at the same time, and the residual current transformer directly detects the leakage current of the electric energy meter outgoing line, and the detected leakage current The magnitude of the current is passed to the controller of the electric operating mechanism part.

The residual current transformer is installed at the incoming line end or the outgoing line end of the circuit breaker part.

The external circuit breaker of the electric energy meter provided by the utility model can measure the leakage current of the outgoing line of the electric energy meter only by adding a simple current transformer or residual current transformer, and control the external circuit breaker according to the measured leakage current Timely disconnect the power supply, so the utility model can disconnect the user's electric energy in time when the electric energy meter user leaks electricity or a grounding fault occurs, realizing the leakage protection function and protecting the personal and property safety of the electricity user; in addition, the utility model is simple to implement , low cost, high reliability.

Description of drawings

Fig. 1 is a schematic diagram of the connection between the cost control smart meter and the external circuit breaker of the electric energy meter in the background technology.

Fig. 2 is a functional block diagram of the application of the utility model on a single-phase electric energy meter.

Fig. 3 is a functional block diagram of the application of the utility model on a three-phase electric energy meter.

detailed description

As shown in Figure 2, it is the functional module diagram of the application of the utility model on the single-phase electric energy meter: the 220V power supply incoming line passes through the ordinary circuit breaker of the electric energy meter and then enters the intelligent fee-controlled electric energy meter, and the intelligent electric fee-controlled electric energy meter has four outlets in total. : Charge control indication signal line, which is connected to the controller of the electric operating mechanism part of the external circuit breaker of the electric energy meter, used for the charge control indication signal; action feedback signal line, which is connected to the electric operation of the external circuit breaker of the electric energy meter On the controller of the mechanism part, it is used for the feedback of the opening and closing state of the circuit breaker; the live wire of the power outlet and the neutral wire of the power outlet, and the two power outlets are connected to the power user through the circuit breaker part of the external circuit breaker of the electric energy meter and supply power.

In this embodiment, there are two current transformers, namely the live wire current transformer and the neutral wire current transformer; the live wire in the outlet line of the electric energy meter passes through the live wire current transformer, and the live wire current transformer is used to detect the live wire at the outlet end of the electric energy meter The current and the detection signal are sent to the controller of the electric operating mechanism; the zero line in the outlet line of the electric energy meter passes through the zero line current transformer, and the zero line current transformer is used to detect the zero line current at the outlet end of the electric energy meter and transmit the detection signal The controller of the electric operating mechanism; the controller judges whether there is a leakage current in the outgoing line of the electric energy meter through the current detected by the current transformer, and sends a control command to control the circuit breaker to disconnect the electric energy meter when the leakage current is greater than the set value. Outgoing wires to ensure the safety of low-voltage power users.

In this embodiment, the live wire current transformer and the neutral wire current transformer are installed at the incoming line end of the external circuit breaker of the electric energy meter at the same time. Similarly, live line current transformers and neutral line current transformers can also be installed at the outlet of the circuit breaker section at the same time.

In addition, the current transformer can also use only one residual current transformer. At this time, the two incoming lines or two outgoing lines of the external circuit breaker of the electric energy meter must pass through the residual current transformer at the same time. When only one residual current transformer is used for the current transformer, the residual current transformer can still be installed at the incoming line terminal or the outgoing line terminal of the circuit breaker part of the electric energy meter external circuit breaker.

As shown in Figure 3, it is a functional block diagram of the application of the utility model on the three-phase electric energy meter: there are four 380V power supply lines, which are A-phase power line, B-phase power line, C-phase power line and N-phase power line , the four power lines go through the ordinary circuit breaker of the electric energy meter and then enter the intelligent cost-controlled electric energy meter. There are five outgoing lines in the intelligent electric cost-controlled electric energy meter: the electric charge control indicator signal line, which is connected to the electric operating mechanism of the external circuit breaker of the electric energy meter On part of the controller, it is used for the charge control indication signal; the action feedback signal line is connected to the controller of the electric operating mechanism part of the external circuit breaker of the electric energy meter, and is used for the feedback of the opening and closing state of the circuit breaker; the A-phase power supply Outlet, B-phase power outlet, C-phase power outlet and N-phase power outlet, the four power outlets are connected to the power user through the circuit breaker part of the external circuit breaker of the electric energy meter and supply power.

In this embodiment, only one residual current transformer is used as the current transformer, and all outgoing lines of the electric energy meter pass through the residual current transformer at the same time, and the residual current transformer directly detects the leakage current of the outgoing line of the electric energy meter, and the detected The magnitude of the leakage current is transmitted to the controller of the electric operating mechanism. According to the current detected by the residual current transformer, the controller judges whether there is a leakage current in the outgoing line of the electric energy meter, and sends a control command to control the circuit breaker to partially disconnect the outgoing line of the electric energy meter when the generated leakage current is greater than the set value, so as to ensure that the low-voltage power users electricity safety

In this embodiment, the residual current transformer is installed at the outlet terminal of the external circuit breaker of the electric energy meter. Similarly, the residual current transformer can also be installed at the incoming line end of the external circuit breaker of the electric energy meter.

In addition, for the three-phase electric energy meter, four current transformers can also be used, which are A-phase current transformer, B-phase current transformer, C-phase current transformer and N-phase current transformer; The power line passes through the A-phase current transformer, and the A-phase current transformer is used to detect the A-phase current at the output terminal of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; the B-phase power line in the electric energy meter outgoing line passes through the B Phase current transformer, B-phase current transformer is used to detect the B-phase current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; the C-phase power line in the electric energy meter outgoing line passes through the C-phase current transformer, The C-phase current transformer is used to detect the C-phase current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; the N-phase power line in the electric energy meter outgoing line passes through the N-phase current transformer, and the N-phase current transformer is used It is used to detect the N-phase current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism. When four current transformers are used, all four current transformers can be installed at the incoming line end of the circuit breaker part at the same time, or all can be installed at the outgoing line end of the circuit breaker part at the same time.

Taking the three-phase electric energy meter as an example below, the working principle of the utility model when multiple current transformers are used is illustrated:

According to Kirchhoff's law, the leakage current is the vector sum of the three-phase current plus the neutral current, that is When the three-phase four-wire distribution line is in normal operation, the three-phase load is unbalanced, and the line leakage current is zero at this time, that is When a ground fault occurs in a certain phase, the vector sum of the detected three-phase current plus the neutral line current is not zero, but equal to the ground fault current.

The controller of the electric operating mechanism separately collects the vector current j of each phase of A, B, C, and N through the current transformer: amplitude (I _A , I _B , I _C , I _N ) and angle (φ _A , φ _B , φ _C , φ _N ), decompose each vector into real parts (I _A I, I _B I, I _C I, I _N I) and imaginary parts (jI _A , jI _B , jI _C , jI _N ) ,Have:

I＝I _A I+I _B I+I _C I+I _N I

J＝jI _A +jI _B +jI _C +jI _N

When a ground fault occurs, the leakage current amplitude I _PE collected by the current transformer:

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; E.</span>}}<span\; class="notranslate">\; =</span>\sqrt{{\mathrm{<span\; class="notranslate">\; I</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

Assuming that the transformation ratio of the current transformer is K, then the ground fault current I _O(d) :

I _O(d) = K×I _PE

The set value (setting value) I _ZdG of the leakage protection of the external circuit breaker of the electric energy meter complies with:

I _O(d) ≤1.3I _ZdG

In order to avoid misoperation, the set value I _ZdG should be 2.5 to 4.0 times greater than the sum of the leakage current of the line and equipment during normal operation, and can be set according to the field application conditions.

During normal operation, the controller of the electric operating mechanism collects and calculates the leakage current (earth fault current) I _O(d) in real time, and compares it with the set value) I _ZdG . When leakage occurs and the leakage current is greater than the set value, that is, I _O(d) >1.3I _ZdG , the control circuit breaker part performs an opening action to cut off the power supply.

Similarly, the single-phase energy meter also uses the same method to detect leakage current.

For the form of using a current transformer, because the power outlets of the electric energy meter all pass through the current transformer; The sum of the vector values of the current should be 0. At this time, the leakage current collected by the current transformer is 0. Once the load of the electric energy meter has a ground fault or leakage, the current collected by the circuit transformer is directly the leakage current. Amplitude I _PE ; the product of I _PE and the transformation ratio K can get the ground fault current I _O(d) , the controller of the electric operating mechanism compares I _O(d) with the set value I _ZdG , when leakage occurs and When the leakage current is greater than the set value, that is, I _O(d) >1.3I _ZdG , the control circuit breaker part performs the opening action and cuts off the power supply, which can also realize the leakage protection function.

Claims (9)

1. An electric energy meter external circuit breaker, comprising an electric operating mechanism part and a circuit breaker part, is characterized in that it also includes a current transformer; the current transformer is installed on the outgoing line of the electric energy meter, and the output terminal of the current transformer is connected to the electric operation The controller of the mechanism part is connected; the current transformer is used to detect the outgoing current of the electric energy meter, and the detected current signal is transmitted to the controller of the electric operating mechanism part; the controller of the electric operating mechanism part is based on the current detected by the current transformer Judging whether there is a leakage current in the outlet of the electric energy meter, and sending a control command to control the circuit breaker to partially disconnect the outgoing line of the electric energy meter when the generated leakage current is greater than the set value, so as to ensure the safety of low-voltage power users. 2. The electric energy meter external circuit breaker according to claim 1, characterized in that said electric energy meter is a single-phase electric energy meter. 3. The electric energy meter external circuit breaker according to claim 2, characterized in that there are two sets of said current transformers, which are respectively a live wire current transformer and a neutral wire current transformer; the live wire in the outgoing line of the electric energy meter passes through The live wire current transformer, the live wire current transformer is used to detect the live wire current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; The device is used to detect the zero line current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism. 4. The electric energy meter external circuit breaker according to claim 3, characterized in that the live line current transformer and the neutral line current transformer can be installed at the incoming line end of the circuit breaker part at the same time, or can be installed at the circuit breaker at the same time The outlet end of the device part. 5. The external circuit breaker with electric energy meter according to claim 1, characterized in that said electric energy meter is a three-phase electric energy meter. 6. The electric energy meter external circuit breaker according to claim 5, characterized in that there are four current transformers, which are respectively A-phase current transformer, B-phase current transformer, C-phase current transformer and N-phase current transformer. Phase current transformer; the A-phase power line in the outlet line of the electric energy meter passes through the A-phase current transformer, and the A-phase current transformer is used to detect the A-phase current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; The B-phase power line in the outgoing line of the electric energy meter passes through the B-phase current transformer, and the B-phase current transformer is used to detect the B-phase current at the outgoing line end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; The C-phase power line passes through the C-phase current transformer, and the C-phase current transformer is used to detect the C-phase current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism; the N-phase power line in the electric energy meter outgoing line passes through Through the N-phase current transformer, the N-phase current transformer is used to detect the N-phase current at the outlet end of the electric energy meter and transmit the detection signal to the controller of the electric operating mechanism. 7. The electric energy meter external circuit breaker according to claim 6, characterized in that the A-phase current transformer, B-phase current transformer, C-phase current transformer and N-phase current transformer can all be installed at the same time At the incoming line end of the circuit breaker part, or all at the same time installed at the outgoing line end of the circuit breaker part. 8. The electric energy meter external circuit breaker according to any one of claims 1, 2 or 5, characterized in that there is only one current transformer, and it is a residual current transformer; all outgoing lines of the electric energy meter pass through at the same time The residual current transformer, the residual current transformer directly detects the leakage current of the outlet line of the electric energy meter, and transmits the detected leakage current to the controller of the electric operating mechanism. 9. The electric energy meter external circuit breaker according to claim 8, characterized in that said residual current transformer is installed at the incoming line end or outgoing line end of the circuit breaker part.