CN2731460Y

CN2731460Y - Theoretical line loss monitor

Info

Publication number: CN2731460Y
Application number: CN 03209091
Authority: CN
Inventors: 曹建凯; 孙晓东; 刘星华; 黄贵森
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-09-09
Filing date: 2003-09-09
Publication date: 2005-10-05
Anticipated expiration: 2013-09-09

Abstract

The utility model discloses a theoretical line loss monitor for monitoring the transit networks of electric power lines. A current mutual inductor detects the size of the three-phase current, and the three-phase current is changed into a voltage signal which can be accepted by an analog-digital converting unit and which is proportional to the current input from one primary side of the current mutual inductor via a signal regulating unit which is composed of amplifiers. The required data is obtained after the voltage signal is collected by a chip microprocessor, converted by the analog-digital converting unit, and calculated and processed by a specific software, and then the data is further sent to a display unit and a serial port communicating unit. The utility model simplifies the measuring and calculating process, improves the accuracy and largely shortens the measuring and calculating periodic time.

Description

The theory wire loss monitor

Technical field

The utility model is a kind of intelligence instrument of the following power line transmission network theory of monitoring 10KV (containing 10KV) line loss, particularly can continual real-time device for monitoring.

Background technology

As everyone knows, in the power transmission and distribution process, the transmission of electric energy and the conversion of electromagnetic energy all realize by electric current.Electric current will produce loss during by lead, in addition, has equipment such as a large amount of transformers, switch, instrument also can consume certain energy in the transmission network of electric power, and above energy loss is called line loss in the power system power supply process.

At present, the measuring and calculating of line loss, examination, management have consequence in the electric power enterprise power supply.The situation that the power distribution station operational factor that power supply enterprise generally runs in distribution operation, operation control can not be grasped in real time; Measuring method for line loss, electric power enterprise generally adopts computing method such as proportion of goods damageds method estimation of platform district and average current method at 10KV and the power distribution station below the 10KV, the secondary network line loss is calculated not accurate enough, and there is subjective error in the process complexity especially in representing day timing meter reading.

Summary of the invention

The measuring and calculating process complexity, the accuracy that have line loss now are not enough in order to overcome, the deficiency of measuring and calculating excessive cycle, the utility model provides a kind of Installation and Debugging convenient, can monitor, show the instrument of line loss amount in real time, has simplified the measuring and calculating process, improve accuracy, greatly must shorten the measuring and calculating cycle.

The technical scheme that its technical matters that solves the utility model adopts is: be the small intelligent monitoring instrument that core and the corresponding interface thereof are formed with the chip microprocessor.Detect the size of three-phase current by current transformer, by the signal condition unit of forming by amplifier, be transformed into can be accepted by AD conversion unit and with the voltage signal of the proportional size of current transformer primary side input current, collection, analog to digital conversion, specific computed in software through chip microprocessor are handled and are obtained needed data, further give display unit and serial communication unit.This device can be obtained the calculating parameters needed by button or serial ports, to adapt to different electric power transmission networks.

Description of drawings

Fig. 1 is a device external form sketch.

Fig. 2 is the principle of device block diagram.

Fig. 3 is a schematic diagram.

Fig. 4 is a signal condition unit enlarged drawing.

Fig. 5 and 6 is a chip microprocessor software processes process flow diagram.

Embodiment

Now further specify the utility model device in conjunction with Figure of description

Fig. 1 is an instrument external form sketch, long 156cm, and wide 115cm, high 36cm, there is the digital display window of 8 LED on instrument surface 1; Mark 2 is 3 LED light windows; Mark 3 is 5 buttons; Mark 4 is three-phase current input port and power input mouth; Mark 5 communicates to connect port for RS232.

The digital display window of 8 LED shows loss of energy, and LED light respectively is the duty lamp, transformer copper loss He Tai district's loss pilot lamp.5 buttons are as input parameter and the usefulness of checking every waste.

Fig. 2-1 mutual inductor unit is made up of 3 high precision small current mutual inductors, is the forward path of picking up signal, directly links to each other with the current transformer CT of Circuit Fault on Secondary Transformer, also will install simultaneously with high-pressure section and isolate, and improves the reliability of device.In Fig. 3, three-phase CT electric current is imported from three pairs of ports respectively, through 3 small current mutual inductor T1, and T2, T3, at T1, T2, the output terminal of T3 obtain the weak current signal of proportional relation, also finish the function of picking up signal.

Fig. 2-2 signal condition unit, form by high performance amplifier, the three-phase current signal that mutual inductor is picked up be transformed into be fit to that AD conversion unit is accepted and with the proportional voltage signal of corresponding phase current that will detect, the control signal that chip microprocessor also can be accepted in this unit changes gain, to adapt to the large-signal conversion of electric net overload.

The details of signal condition unit has been described in Fig. 4.The signal condition unit by 4 amplifier amplifier U3 (A, B, C, D), 4 path analoging switch U10 (A, B, C, D) and the chip periphery components and parts form.

With an explanation mutually wherein, remaining two-phase is identical.

Among Fig. 4, the change-over circuit that the weak current signal that obtains from the output terminal of current transformer T1 is formed through U3A, the reference voltage at the normal phase input end 2.5V of stack (Base Ref/2) of U3A makes raise the zero point of ac voltage signal.Output terminal 1 pin of U3A output 0 under the normal condition ~+ac voltage signal of 5V.

(C) analog switch takes turns the negative-phase input of the regular U3D of switching to three-phase current signal to U10 among Fig. 4 for A, B, reaches the effect of timesharing.

Among Fig. 4 U3D and U10D form controlled amplifying circuit the signal of prime zoomed into 0 ~+AC signal of 5V, this grade amplifying circuit is that gain is 4 times under normal condition, and under overload conditions, make gain drop to 1 times to the control of U10D by chip microprocessor.So under normal condition, guarantee precision, also can adapt to the situation of overload and do not reduce measurement range and precision, reached the voltage request that suitable A/D handles.

Fig. 2 chip microprocessor unit, because the develop rapidly of semiconductor industry, the utility model adopts powerful microprocessor and specific software, finishes signals collecting, processing, calculating, control, demonstration and communicates by letter.

U1 and peripheral device are formed the chip microprocessor unit in Fig. 3 schematic diagram.

Its software processes flow process is as illustrated in Figures 5 and 6:

Software processes is divided two main modular, timing sampling module and general task processing module.

Fig. 5 has shown the workflow of timing sampling module, finishes the signals collecting of three-phase in the timing sampling module, the flow process that adds up.This module and general task processing module are asynchronous execution, according to the time numeration zone bit are set, and carry out step by step for the task in the general task processing module.

Module routine is to the current waveform discretize, and sample frequency is 15KSPS, the three-phase current data stream that obtains, through square, the transient power original value that adds up and obtain electric current; After finishing 16384 A/D conversions, zone bit further is set and shifts original value for general task processing module processing.

Fig. 6 has shown the workflow of general task processing module, and general task processing module is finished the task in the flow graph 6.

General task processing module is to trigger by zone bit, and each task is carried out in inquiry;

After calculating finish back or input processing, the display process task is according to the different content of corresponding marker bit demonstration at every turn.

It is to make corresponding processing at the input of button and RS232 that input is handled.

It is the program of getting in touch with host computer that communication is handled, and is responsible for the transmission of data, the acceptance of command parameter.

The calculating of loss of energy is that the original value that will obtain in the timing sampling module further calculates desired value.Calculating to its energy loss is the mathematical model that adopts the power distribution network substitutional resistance.After parameter calculates according to distribution network, by communication interface or press key input device.Parameter and basis People's Republic of China (PRC) power industry standard " power network line losses calculating guide rule " DL/T 686-1999, " rural power grids power-saving technique rules " DL/T738-2000.

Stores processor is with parameter, end value, and important intermediate value is stored in EEPROM, prevents loss of data after the power down.

Fig. 2-6 communication unit is made up of U2 and peripheral components and parts in Fig. 3.Serial ports adopts RS-232 communication, can be directly and the host computer on-line communication, and as the passage that parameter is imported and data result is exported.

Fig. 2-7 power unit is a P cock power module, can be at the voltage power supply that exchanges under 90V ~ 260V.

In concrete enforcement, this device is sealed in the current transformer CT loop of platform district supply transformer (10KV or 10KV are following) low-pressure side, the method of attachment of noting three-phase current with whether firmly be connected, this device does not influence the normal use of other instrument and instrument in the CT loop.After to parameters such as this device input wires mode, substitutional resistances, can automatically calculate the line loss amount of power line transmission network in real time, and show with kilowatt/hour energy unit.

Claims

1, a kind of theory wire loss monitor, comprise current transformer, signal condition unit, unit microprocessor, display unit and serial communication unit, it is characterized in that: described current transformer is made up of 3 high precision small current mutual inductors, forward path for picking up signal, directly link to each other with the current transformer CT of Circuit Fault on Secondary Transformer, also will install simultaneously with high-pressure section and isolate, three-phase CT electric current is respectively from three pairs of port inputs; The signal condition unit is made up of high performance amplifier; Unit microprocessor is divided into two main modular, time block and general task processing module, the serial communication unit is made up of U2 and peripheral component, serial ports adopts RS-232 communication, directly and host computer online, as a passage of parameter input and output, the instrumentation table of display unit has been worn 8 LED digital display windows.

2, theory wire loss monitor according to claim 1 is characterized in that: worn 5 buttons of 3 LED light windows, three-phase current input port and power input mouth at instrumentation table, also had RS-232 communication link port.

3, theory wire loss monitor according to claim 1 is characterized in that: three-phase CT electric current is respectively from three pairs of port inputs, through 3 small current mutual inductors.

4, theory wire loss monitor according to claim 1 is characterized in that: the signal condition unit is by 4 amplifier amplifier U3, and 4 path analoging switch U10 and chip periphery components and parts are formed.