CN201286016Y - Voltage passive control apparatus - Google Patents

Abstract

The utility model relates to a voltage and reactive power control device suitable for on-load voltage regulation of two transformers running in parallel, comprising an automatic regulator of on-load voltage regulation switches of two transformers connected in the same substation and a voltage and reactive power control device between switching capacitor groups. The compensation control device is composed of power conversion, power collection, central control, switch input and output and control, alarm output and other units. The power conversion unit is connected to the central control unit through the power collection unit. The switch input terminal of the central control unit is connected to the switch The output terminal of the quantity input unit is connected, and the switch quantity output terminal of the central control unit is respectively connected to the input terminals of the switch quantity output unit and the control alarm output unit. The device can be used to accurately and reliably adjust the taps of the transformers when the transformers are running in parallel or in parallel, ensuring stable and reliable operation of the substation. At the same time, the device also has functions such as reactive power compensation control.

Description

Voltage reactive power control device

technical field

The utility model belongs to the technical field of electric power automatic control equipment, and relates to a voltage and reactive power control device used in electric power systems and substations, in particular to a voltage and reactive power control device suitable for two on-load voltage regulating transformers running in parallel.

Background technique

In the power supply system, voltage stability is an important index for assessing the quality of power supply and an important parameter for system operation. The transmission of system reactive power will not only reduce the transmission capacity of the system, but also increase the line loss, reduce the working efficiency of the power equipment in the power supply system, cause power waste and reduce the quality of power supply.

In recent years, in order to improve the power supply quality of the power system, stabilize the voltage, and reasonably compensate reactive power, on-load tap changer transformers and power capacitor banks with appropriate capacity are generally installed in substations of various voltage levels. How to reasonably adjust and control the on-load tap changer and power capacitor bank has become the key to improving the quality of power supply, the efficiency of power transmission and transformation, and reducing line loss.

There are two main forms of on-load tap-changing transformer control currently used, one is the VQC controller, and the other is a dedicated transformer on-load tap-changing controller. In practical applications, when two transformers are operated in parallel in a substation, the voltage regulation and control of the transformers can be basically realized by using the above two controllers, but when the two transformers are operated in parallel (especially when the voltage regulation of the two transformers When the taps are not consistent), since the two controllers control the two transformers separately, the adjustment control process is not easy to synchronize, which may generate a circulating current between the two transformers. Therefore, the existing OLTC controller is in The parallel operation of two transformers generally does not use automatic input, but can only be operated manually, which is difficult to meet the operation requirements of unattended or few-attended substations. As far as system compensation of reactive power is concerned, with the development of reactive power compensation technology, various compensation methods, from static compensation to dynamic compensation, from contact compensation to non-contact compensation, have achieved certain progress. However, there are still some practical problems, such as reactive power transfer problem, resonant wave problem, compensation method problem, reliability and accuracy of the control device, etc. These problems still need to be resolved by those skilled in the art. further research to resolve.

Utility model content

The purpose of the utility model is to solve the problems existing in the prior art, and provide a voltage and reactive power control device with reasonable structure, reliable operation, flexible and convenient configuration and installation, and automatic voltage regulation when on-load tap changer transformers operate in parallel.

The voltage and reactive power control device designed to achieve the purpose of the above invention is a voltage and reactive power compensation control device connected between the automatic regulators of two transformer on-load tap changers and the switching control terminals of the switching capacitor bank. It is composed of conversion unit, power collection unit, central control unit, switch input unit, switch output unit, control, alarm output unit and power supply. The output end of the power conversion unit is connected to the digital signal input of the central control unit after passing through the power collection unit. The switch input terminal of the central control unit is connected with the output terminal of the switch input unit, and the switch output terminal of the central control unit is connected with the input terminal of the switch output unit and the input terminal of the control and alarm output unit. In the actual control process, the real-time parameter acquisition adopts the power conversion unit (power transmitter) to realize the conversion of various power frequency quantities, and then performs data sampling through the power acquisition unit (high-speed A/D conversion module), and integrates various on-site operations. State, adopts programmable computer controller (central control unit, adopts PP41 programmable computer controller of B&R Company, referred to as PPC) for rapid analysis and calculation and intelligent decision-making, and finally controls the control and alarm output unit through the switch output unit.

The principle of using this device to control the voltage regulation of the transformer is: when the transformer is in the non-parallel operation mode, it is discretely controlled, and the method of voltage control is adopted; when the transformer is in the parallel operation mode, the control idea is to keep the two transformers in the Operate under the same transformation ratio as possible. During the adjustment process, first adjust the transformer with a small step difference, then adjust the transformer with a large step difference, and then adjust the transformer with a small step difference, and keep the minimum step difference during adjustment; when the first transformer After the adjustment, the second transformer will no longer be executed. When the second transformer issues an adjustment command, the first transformer should return to the original gear. Correspondingly, the switching control of the switching capacitor bank is based on the principle of combining the system reactive power deficit and reactive power development trend, and considering the influence of voltage and power factor, the switching of the capacitor bank is determined. In order to ensure the reliability of the operation of the compensation device, functions such as switching period control, blocking control, and fault alarm are set in the control device. Considering the flexibility of the operation of the compensation device, in the control device, the local manual control and automatic control blocking switching function, status data display function and data communication function are set.

Compared with the prior art, the device described in the utility model mainly has the following characteristics:

1. The utility model aims at the requirement of parallel operation of two transformers with inconsistent voltage regulation taps in this field and the actual situation of the reactive power compensation device. Without changing the operation state of the transformer and the capacitor bank, the utility model can make full use of the regulation. It has a particularly important role and significance in improving the quality of power supply and reducing the loss of lines and main power equipment, and also has a wide range of promotion and application value.

2. For the first time, the device introduces the design concept of phase object in the system design. Based on various component models, the advanced PCC technology is used to develop the voltage and reactive power control device, which not only greatly improves the reliability of the developed voltage and reactive power control device. At the same time, the configuration of the device is simple and convenient, and it has strong adaptability and flexibility. It is suitable for substations with typical wiring and operation modes of two on-load tap changer transformers. The output control amount can be expanded according to the number of capacitor banks. .

3. Introduce the control idea of separate implementation and coordination of voltage regulation and reactive power compensation control, which conforms to the design principle of risk dispersion, and improves the reliability and flexibility of substation equipment operation.

4. Use real-time operating parameters and equipment parameters for voltage prediction, and use the intelligent control scheme of self-adaptive operation mode and self-adaptive operation state to improve the operation flexibility of substation equipment, effectively reduce the number of operations of voltage regulating devices and capacitor switching, and improve the reliability of the device.

5. It has a variety of standard communication interfaces, which can be connected to remote or local communication networks, and can realize voltage regulation and reactive power network control, and implement voltage and reactive power optimization.

Description of drawings

Fig. 1 is a system structure diagram of the utility model.

Fig. 2 is a schematic structural block diagram of a specific embodiment of the utility model.

Detailed ways

The following will further explain the structural and functional content of the utility model, the switching control principle of the switching capacitor bank and the operation mode of the automatic adaptation substation in conjunction with the accompanying drawings.

1. The actual structural composition and function of each component in the device

Referring to the accompanying drawings, the utility model relates to an automatic regulator of on-load tap changers of two transformers B1 and B2 in the same substation and switching control terminals of switching capacitor banks C ₁₁ , C ₁₂ , C ₁₃ , and C ₁₄ The voltage and reactive power compensation control device, its hardware design is mainly composed of power conversion unit, power acquisition unit, central control unit (PPC), switch input unit, switch output unit, control, alarm output unit, power supply, etc. In terms of component connection structure, the output end of the power conversion unit is connected to the digital signal input end of the central control unit after passing through the power acquisition unit, the switch input end of the central control unit is connected to the output end of the switch input unit, and the switch of the central control unit The quantity output terminal is connected with the input terminal of the switch quantity output unit and the input terminal of the control and alarm output unit. The structure composition and function of each working unit are as follows.

1. Power conversion unit

The power conversion unit is mainly used to realize the function of converting the measured power into a linear proportional DC voltage output. This device uses the GP series power transmitter of the Sino-foreign joint venture Haiyan Pubo Electric Co., Ltd., including the voltage transmitter shown in Figure 1. Converters and power transmitters are used to complete the conversion of voltage, active power and reactive power.

The GP series power transmitter adopts a large-scale transmitter special chip manufactured by ASIC technology, which has excellent temperature characteristics and long-term stability, good resistance to electrical shock and overload performance, high-level accuracy and linearity, and does not require Frequent validation and maintenance, in full compliance with the requirements of IEC, ANSI, BEAMA and other standards.

2. Power collection unit

The power acquisition unit is a unit that converts analog signals into digital signals. This unit uses two AI354 analog input modules of B&R2000 series. The input signal of this module is +/-10V, 12-bit resolution, and the linearity error is <0.1%. Input impedance >20MΩ, each module has 4 input channels.

3. Central control unit (PPC)

The central control unit is the core of the device, which is used to realize various numerical calculations, logical operations and control algorithms. The unit adopts B&R's PP41 programmable computer controller, and the programmable computer controller (PPC) represents a new control Concept, it integrates the standard control functions of programmable logic controller (PLC) and the analysis and computing capabilities of industrial computers, installs a real-time multi-tasking operating system, uses high-level programming language for modular programming, and provides a wide range of solutions for realizing various intelligent control algorithms Good development foundation. PCC also has an advanced fieldbus communication system, which can form various networks through CAN, RS232, RS485, PROFIBUS, ETHERNET, etc. It is a relatively perfect automatic control device. The voltage and reactive power control device developed by it is not only reliable High performance, and powerful, fully meet the requirements of optimal control of voltage and reactive power. The CPU in this device product has multi-tasking processing function, has a hardware watchdog circuit, its instruction cycle is 0.8 microseconds, the real-time clock resolution is 1 second, and it provides two standard communication interfaces of RS232 and CAN.

4. Switch input unit and switch output output unit

The switch value input and output unit is the unit that converts the state or event signal into a digital signal input to the PPC or converts the digital signal output by the PPC into a switch value output unit. Both units use the B&R PP41 series self-contained module, which has 16 switches Quantity input channel and 20 switch quantity output channels.

5. Control and alarm output unit

The control and alarm output unit adopts relay output, and the relay adopts Omron relay. The switching control circuit driven by the control and alarm output unit adopts GU type, the technical parameters are: contact capacity: 30A, electrical life: 100,000 times, safety certification: UL E141060; the signal output circuit adopts MI 2ploes type, technical parameters For: contact capacity: 5A, electrical life: 100,000 times, safety certification: UL E141060.

6. Power supply

The power supply adopts AC/DC24V switching power supply, and the allowable input voltage range: 180V--240V.

2. The principle of capacitor switching control

According to the principle of combining the reactive power demand of the system with the predicted value of voltage change, comprehensive judgment is made to control capacitor switching. The voltage is divided into 6 files:

The first gear voltage>Umax strongly cuts the capacitor.

The second gear voltage < Umax and voltage ≥ Umax-UD only cut off.

The third gear voltage <Umax-UD and voltage ≥Umin+UD are switched normally.

The fourth gear voltage <Umin+UD and voltage ≥Umin can only be switched but not cut.

The fifth gear voltage <Umin and voltage ≥ 7.5KV strong investment capacitor.

The sixth gear voltage <7.5KV strongly cuts the capacitor.

UD: After the capacitor is switched on or off, the voltage change value.

Capacitor input action conditions: When the voltage is in the third and fourth gears, the measured reactive power is greater than the set input reactive power value, and the device issues a capacitor input command. When the voltage is in the fifth gear, the device sends out a capacitor strong throw command.

Capacitor cut action condition: When the voltage is in the second and third gears, the measured reactive power is less than the set cut reactive power value, and the capacitor is cut off. When the voltage is in the first gear and the sixth gear, the device sends out a command to force the capacitor to be cut.

3. Automatically adapt to the operation mode of the substation

A. Bus section operation: bus tie circuit breaker 100 is in the open state, 101 circuit breaker is closed, and the switching of C11 and C12 is controlled according to the measured value U101, Q1; 102 circuit breaker is closed, and C21, C21, are controlled according to the measured value U102, Q2 Switching of C22.

B. Non-segmented operation of the busbar (1): The bus tie circuit breaker 100 is closed, the circuit breaker 101 is closed, and the circuit breaker 102 is open. At this time, control C11, C12, C21, Switching of C22. Pay attention to the coordination of the two voltages of U101 and U102 during work: if one of the voltages is less than 0.75Ue and the other voltage is normal, it is considered that the voltage circuit of one side of the bus is disconnected, and the normal voltage is the control value.

C. Non-segmented operation of the bus (2): The bus tie circuit breaker 100 is closed, the circuit breaker 102 is closed, and the circuit breaker 101 is open. At this time, control C11, C12, C21, Switching of C22. Pay attention to the coordination of the two voltages of U101 and U102 during work: if one of the voltages is less than 0.75Ue and the other voltage is normal, it is considered that the voltage circuit of one side of the bus is disconnected, and the normal voltage is the control value.

D. Non-segmented operation of the bus (3): The bus tie circuit breaker 100 is closed, and the circuit breakers 101 and 102 are both closed. At this time, the switching of C11, C12, C21, and C22 is controlled according to the measured values U101, U102, (Q1+Q2) Cut; pay attention to the coordination of the two voltages of U101 and U102 during work: if one of the voltages is less than 0.75Ue and the other voltage is normal, it is considered that the voltage circuit on one side of the bus is disconnected, and the normal voltage is the control value.

Fourth, the principle of transformer on-load voltage regulation control

When the transformers are in the non-parallel operation mode, they are discretely controlled, and the method of voltage control is adopted; when the transformers are in the parallel operation mode, the control idea is to keep the two transformers operating at the same transformation ratio as possible. During the adjustment process, Adjust the transformer with a small step difference first, then adjust the transformer with a large step difference, and then adjust the transformer with a small step difference, and keep the minimum step difference during adjustment; when the first transformer is adjusted, the second transformer will not execute the adjustment command. , the first transformer should return to the original gear.

Claims (3)

1, a kind of voltage and reactive power control system comprises that one is connected in same transformer station two transformers (B1, B2) on-load voltage regulating switch automatic regulator and opening-closing capacitor bank (C ₁₁, C ₁₂, C ₁₃, C ₁₄) the switching control end between the voltage and reactive power compensation control device, it is characterized in that it is by the electric weight converting unit, the electric quantity acquisition unit, central control unit, the switching value input unit, switching value output unit and control, the warning output unit is formed, the output of electric weight converting unit passes to the digital signal input end of central control unit behind the electric quantity acquisition unit, the switching value input of central control unit connects with the output of switching value input unit, the switching value output of central control unit and the input and the control of switching value output unit, the input of warning output unit connects.

2, voltage and reactive power control system according to claim 1 is characterized in that said central control unit and switching value input and output unit adopt the PP41 programmable computer controller that carries switching value input, output module.

3, voltage and reactive power control system according to claim 1 is characterized in that said electric weight converting unit is made of GP series electric parameters transducer, comprises voltage transmitter and power transducer.

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