CN201141903Y - Substation three-phase flow simulation load tester - Google Patents

Abstract

A three-phase through-current simulation load tester, including a current output circuit, a current sampling circuit, a measurement and control device and a controller, the current output circuit is connected to the measurement and control device and the current sampling circuit, and also includes a three-phase power supply circuit, single-phase/three-phase Variable current source, three-phase voltage source, single-phase/three-phase variable current source including current coarse adjustment circuit and current amplification circuit, three-phase power supply circuit connected to current coarse adjustment circuit, current coarse adjustment circuit connected to current amplification circuit, current amplification circuit Connect the current output circuit; the three-phase power supply circuit is connected to the sampling tracking circuit, the sampling tracking circuit is connected to the phase-shifting amplitude circuit, the phase-shifting amplitude circuit is connected to the voltage power amplifier circuit, the voltage power amplifier circuit is connected to the voltage sampling circuit, the current output circuit, the current sampling circuit, and the sampling tracking circuit The circuit, the current coarse adjustment circuit, the phase shift amplitude circuit and the voltage sampling circuit are connected to the controller. The utility model has good safety, is convenient to use and can improve work efficiency.

Description

Substation three-phase flow simulation load tester

technical field

The utility model belongs to a load tester for substation flow simulation with load.

Background technique

At present, the single-phase current flow method commonly used in China only outputs current and can verify the transformation ratio of CTs, but it cannot check the polarity of all CTs, especially the transformer protection CTs used. If the load current is small, the CT transformation ratio and polarity cannot be verified correctly through the load test, and can only be guaranteed by the through-current test. The test of the device can reliably and conveniently ensure the correctness of the CT transformation ratio and polarity of the substation.

Contents of the invention

In order to overcome the deficiencies of the existing through-current simulation with load test equipment, which can only verify the transformation ratio of the CT of the substation, cannot check the CT polarity, and have poor experimental reliability, the utility model provides a kind of high reliability, which can simultaneously measure the transformation Substation CT transformation ratio and polarity substation three-phase through-current simulation with load tester.

The technical scheme that the utility model solves its technical problem adopts is:

A three-phase through-current simulation load tester for a substation, comprising a current output circuit, a current sampling circuit, a measurement and control device and a controller, the current output circuit is connected to the measurement and control device and the current sampling circuit, the current output circuit and the current sampling The circuit is connected to the controller, and the substation three-phase flow simulation belt load tester also includes a three-phase power supply circuit, a single-phase/three-phase variable current source, and a three-phase voltage source, and the single-phase/three-phase variable current The source includes a current coarse adjustment circuit and a current amplification circuit, the three-phase power supply circuit is connected to the current coarse adjustment circuit, the current coarse adjustment circuit is connected to the current amplification circuit, the current amplification circuit is connected to the current output circuit, and the current coarse adjustment circuit Connect the controller; the three-phase power supply circuit is connected to the sampling tracking circuit, the sampling tracking circuit is connected to the phase-shifting amplitude circuit, the phase-shifting amplitude circuit is connected to the voltage power amplifier circuit, the voltage power amplifier circuit is connected to the voltage sampling circuit, and the sampling The tracking circuit, the phase shifting amplitude circuit and the voltage sampling circuit are connected with the controller.

Further, the current output circuit includes Ia, Ib and Ic, the output terminal of Ia is assembled in the main box, and the output terminals of Ib and Ic are assembled in the auxiliary box.

The beneficial effects of the utility model are mainly manifested in: 1. The utility model has good reliability and can measure the transformation ratio and polarity of the CT of the substation at the same time; 2. The structure is simple and easy to carry.

Description of drawings

Fig. 1 is the circuit schematic diagram of the utility model's three-phase through-current simulation load tester for a substation.

Figure 2 is a circuit diagram of the voltage section.

Figure 3 is a circuit diagram of the current part.

Figure 4 is a circuit diagram of the power supply regulator.

Figure 5 is a schematic diagram of the voltage phase control part.

Figure 6 is a circuit diagram of the CPU measurement and control part.

Figure 7 is a partial circuit diagram of the power transformer.

Figure 8 is a circuit diagram of the phase sequence detection part of the three-phase power supply.

Fig. 9 is a schematic diagram of the on-site wiring of the present invention.

Figure 10 is a block diagram of the main program.

Detailed ways

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

Referring to Figures 1-10, a substation three-phase through-current simulation load tester includes a current output circuit 1, a current sampling circuit 2, a measurement and control device 3 and a controller 4, and the current output circuit 1 is connected to the measurement and control device and The current sampling circuit 2, the current output circuit 1 and the current sampling circuit 2 are connected to the controller 4, and the substation three-phase flow simulation load tester also includes a three-phase power supply circuit 5, a single-phase/three-phase variable current source, a three-phase voltage source, the single-phase/three-phase variable current source includes a current coarse adjustment circuit 6 and a current amplification circuit 7, the three-phase power supply circuit 5 is connected to the current coarse adjustment circuit 6, and the current coarse adjustment circuit 7 is connected to the current amplification circuit 7, the current amplification circuit 7 is connected to the current output circuit 1, the current coarse adjustment circuit 7 is connected to the controller 4; the three-phase power supply circuit 5 is connected to the sampling tracking circuit 8, and the sampling tracking circuit 8 Connect the phase-shift amplitude circuit 9, the phase-shift amplitude circuit 9 is connected to the voltage power amplifier circuit 10, the voltage power amplifier circuit 10 is connected to the voltage sampling circuit 11, and the sampling tracking circuit 9, the phase-shift amplitude circuit 10 and the voltage sampling circuit 11 are connected controller4.

The current output circuit includes Ia, Ib and Ic, the output end of Ia is assembled in the main box, and the output ends of Ib and Ic are assembled in the auxiliary box.

In Figure 1, the power supply part is powered by a three-phase power supply, and the working power supply of the electronic circuit is obtained by stepping down the UA transformer and rectifying and stabilizing the voltage to generate auxiliary power supplies of various voltage levels required for the work. Partially working energy.

The current loop is composed of a current coarse adjustment relay, a current amplification transformer, and a current output fine adjustment power amplifier. The output terminal introduces current sampling, and the signal is fed back to the CPU unit, and the control of each part is directly controlled by the CPU.

The voltage loop is composed of sampling tracking synchronization, phase shift amplitude control, and voltage power amplifier. The output terminal introduces voltage sampling, and the signal is fed back to the CPU unit. The control of each part is directly controlled by the CPU.

The connection relationship between each part: the current and voltage loops are independent of each other, and the two parts of the circuit are connected to the independent interface independently of the CPU, and are also independent of their respective main power supplies. The current loop adopts a three-phase step-down power supply, and the voltage loop adopts ± 80V power supply, power amplifier circuit and small signal amplification and control part adopt isolation and coupling measures.

In the embodiment shown in Figure 2, this part of the circuit uses ±80V as the main power supply. Q101, Q102, Q103, Q104 and R103, R104, R105, R106, R107, R108, L101, R109 group successfully put the output stage. D101, R110, and C103 form a voltage sampling circuit and connect to the CPU voltage sampling terminal. The driving stage of the voltage power amplifier uses +12V as the power supply, and uses T101 to isolate and couple the two parts. U101 and peripheral components form the driving stage, and U-j+ comes from the voltage amplitude and phase sequence control circuit.

The instrument contains three sets of the same voltage control circuits, which are Ua, Ub, and Uc, which together form a three-phase voltage output.

During the working process, the U-j+ signal is amplified by the driver stage and then sent to the power amplifier circuit through the isolation coupler to amplify again and output a relatively large voltage signal. That is, the three-phase output voltage Ua, Ub, Uc of the instrument.

In the embodiment shown in Figure 3, this part of the circuit directly uses AC220V as the main power supply, and the current amplification transformer T201 is a multi-winding transformer. It is two identical windings, which can work in series or in parallel. When connected in series, the output voltage is 2U and the current is 1I; when connected in parallel, the output voltage is 1U and the current is 2I. J201, J202, J203, and J204 form a current coarse adjustment switch, which is directly controlled by the CPU. Q201, Q202, Q203, Q204, R201, R202, R203, R204, R205, R206, D201, D202 form the current fine-tuning power output stage, the voltage signal from T201 is output by D201, D202, synchronously rectified and then output through the power amplifier circuit , this part of the circuit works with 0-100A, so that the output of the instrument can be continuously adjusted from 0-100A. When the output is greater than 100A, the CPU controls J205 to power on. The output current is adjusted stepwise by J201, J202, J203, and J204. D203, R212, R211, and C204 form a current sampling circuit and connect to the CPU current sampling terminal. The driving stage of the current power amplifier uses +12V as the power supply, and T202 is used to isolate and couple the two parts. U201 and peripheral components form the driving stage, and I-j+ comes from the D/A conversion output circuit of the CPU.

The instrument contains three sets of the same current control circuits, which are respectively Ia, Ib, and Ic to form a three-phase current output.

During the working process, the I-j+ signal is amplified by the driver stage and then sent to the power amplifier circuit through the isolation coupler to amplify again and output a relatively large current signal. That is, the three-phase output current Ia, Ib, Ic of the instrument.

In the embodiment shown in FIG. 4, U301, U302, U303, and U304 are all three-terminal voltage stabilizing devices, and the working process is rectification, filtering, voltage stabilizing, filtering, and output. The ±80V power supply is directly rectified and filtered by AC65V×2.

In the embodiment shown in Figure 5, R603, C601, R604, C602, R605, C603, R606, and C604 form an RC phase-shifting circuit, each stage achieves a phase shift of 60 degrees, Ub phase lags Ua by 120 degrees, and Uc phase lags 120 degrees of Ub. R601, R602, and J601 form a voltage switching circuit. When J601 is pulled in, the three-phase output voltage can be equal. When J601 is released, the voltage values of Ub and Uc can be set by R601 and R602 respectively to form three different voltages. , it is convenient to judge the difference.

During the working process, the phase shift control signal sent by the CPU is capacitively coupled and output to Ua-j+, Ua is output to Ub-j+ after 120 degree phase shift, and Ub signal is output to Uc-j+ after 120 degree phase shift.

In the embodiment shown in FIG. 6, U501 is a CPU, and U502 is a D/A conversion circuit, both of which use +12V working power. LCD501 is a display circuit, and AN1-6 are buttons. The three-phase current sampling signal I-i+, the three-phase voltage sampling signal U-u+, and the power phase synchronization signal 6V-1-2 are all sent to the A/D conversion input terminal of U501. The current output adopts off-chip D/A conversion circuit, and the I/O port of U501 is connected to each port of U502, and the output terminal of U502 outputs the three-phase current signal I-j+ after passing through the filter circuit composed of R531C505, R532C504, and R533C506. J201, J202, J203, J204, J205, J601 are controlled by U501 respectively.

In the embodiment shown in Fig. 7, T401 is a multi-winding power transformer, which can output various working power and synchronous power.

In the embodiment shown in Figure 8, U701 is a power supply phase detection circuit, and the peripheral resistor is a signal attenuation resistor to prevent overvoltage of the chip. The working power of U701 uses +12V. When the phase sequence of input UaUbUc is correct, D701 does not light up. When the phase sequence of the input signal is wrong, D701 lights up for alarm.

In the embodiment shown in Figure 9, the three-phase primary flow device verifies the flow pressure of the on-site CT and PT. When the data displayed by the measurement and control device is consistent with the output signal of the three-phase primary flow device, it means that the external circuit is connected correctly. Otherwise, it is necessary to check whether each connection point is correct, and it is very convenient to carry out online testing on each part. Among them, the access point selection, the voltage access point is the corresponding access point after the PT is disconnected for the second time, the current access point is the starting point of the circuit to be verified, and the intermediate associated switches are closed, and the end point is short-circuited with a wire , in order to form a current loop.

In the embodiment shown in FIG. 10, the workflow of the CPU program is listed.

Introduction to the entire working process of the instrument: the working power supply of the instrument is a three-phase four-wire system, and the output voltage is a three-phase four-wire system. There are two working modes for the voltage, mode one: Ua=Ub=Uc=60V; 60, Ub=40, Uc=20. The output current is a three-phase six-wire system. There are two connection methods according to the connection method (switching of the external connection piece of the instrument). The hourly output current is 2I, the output voltage is 1U; there are two ways to adjust the current output, way 1: continuous adjustment, 0-100A; way 2: step adjustment, 100A-300A divided into 5 levels.

When the instrument is powered on, the system is initialized, and each output is zero.

a. Change the output current: When pressing the current + (or current -) key, the output current of the instrument will rise (or fall) at the same time. When it is in the range of 0-100A, it will rise continuously until it is greater than 100A. When the current is turned into a step adjustment , each time the current + (or current -) is pressed, the current changes by 40A, and the three-phase current with a phase difference of 120 degrees.

b. Change the output voltage: when pressing the voltage key, the output of the instrument will be switched between Ua=Ub=Uc=60V Ua=60; Ub=40; Uc=20 Ua=Ub=Uc=0V, and the phase difference is 120V degrees of three-phase voltage.

c. Change the phase of the output voltage and current: the initial phase of the voltage and current is 0 degrees, and the source voltage of phase A is used as the reference phase. When the phase + (or phase -) key is pressed, the output voltage phase of the instrument will change accordingly. Change 1 degree, continuously adjustable within the range of 0-360 degrees, continuously press the button to accelerate adjustment, 0-360 degrees cycle display.

Instrument self-check and protection:

a. Three-phase power phase sequence detection alarm, when the three phases of the instrument are connected to the wrong phase of the power supply, the alarm will be output.

b. Voltage output overload protection, the CPU will judge according to the pressure difference, and when the output is overloaded, it will cut off the output and give an alarm.

c. For current output overload protection, the CPU will judge according to the output current. When the output is overloaded, it will cut off the output and give an alarm.

d. Current delay protection. This instrument is designed for short-time work. When the output is large current, the output will be cut off and an alarm will be issued when the set time is reached.

Claims (2)

1. A substation three-phase through-current simulation load tester, comprising a current output circuit, a current sampling circuit, a measurement and control device and a controller, the current output circuit is connected to the measurement and control device and the current sampling circuit, the current output circuit and the current sampling circuit The current sampling circuit is connected to the controller, and it is characterized in that: the three-phase through-flow simulation load tester also includes a three-phase power supply circuit, a single-phase/three-phase variable current source, and a three-phase voltage source, and the single-phase/three-phase The variable current source includes a current coarse adjustment circuit and a current amplifying circuit, the three-phase power supply circuit is connected to the current coarse adjustment circuit, the current coarse adjustment circuit is connected to the current amplifying circuit, the current amplifying circuit is connected to the current output circuit, and the current The coarse adjustment circuit is connected to the controller; the three-phase power supply circuit is connected to the sampling tracking circuit, the sampling tracking circuit is connected to the phase-shifting amplitude circuit, the phase-shifting amplitude circuit is connected to the voltage power amplifier circuit, and the voltage power amplifier circuit is connected to the voltage sampling circuit, The sampling tracking circuit, the phase shifting amplitude circuit and the voltage sampling circuit are connected with a controller. 2. The three-phase through-current simulation load tester for substation according to claim 1, characterized in that: said current output circuit includes Ia, Ib and Ic, the output end of Ia is assembled in the main box, and Ib and Ic The output end is assembled in the auxiliary box.

Images