A kind of high voltage DC transmission converter valve performance test voltage source
Technical field
The invention belongs to the high voltage DC transmission converter valve performance test field, relate in particular to a kind of high voltage DC transmission converter valve performance test voltage source.
Background technology
Along with the development of electric power system high voltage direct current transmission project, the converter valve of high-power thyristor device series connection becomes the core of DC transmission engineering current conversion station.Its cost generally accounts for about 25% of total investment of engineering, and its quality directly has influence on the reliability of power transmission and transformation system.
The operation test of converter valve is in order effectively to verify the operation characteristic of converter valve, can to satisfy the DC transmission system service requirement to guarantee converter valve, guaranteeing system safety and reliability service.IEC has formulated relevant operation test standard specially for this reason, and the operation test project has been done detailed explanation.In order to examine the performance of converter valve, the method for many in the world employing synthetic test loops is finished the pilot project of IEC regulation in recent years.Synthetic test loop adopt two independently the voltage and current origin system overlap by control system and apply the mode of test voltage and electric current, the actual motion characteristic of test product valve is examined.
Converter valve operating test voltage source, requirement can the fast-response control orders, stablely boost fast, provide test required stable state high pressure in each cycle for test product valve.At present, the voltage source of taking in the used synthetic test loop of converter valve operating test generally is by step-up transformer voltage to be raise, then by thyristor 6 fluctuation bridge rectifications, and output dc voltage; Then to capacitor group charging, the conducting by aux. control valve provides high pressure to test product valve.By control thyristor 6 fluctuation bridge trigger angle test voltage is regulated during the work of this voltage source, because load end is a capacity load, the governing response time is long, and adjustable range is limited, and when output was hanged down test voltage, the stability of a system was relatively poor simultaneously.
Summary of the invention
The purpose of this invention is to provide a kind of high voltage direct current converter valve operation test voltage source, to solve problems such as existing voltage source response speed is slow, adjustable range is limited.
For achieving the above object, the present invention adopts following technical scheme: comprise transformer, auxiliary main circuit, the primary side of described transformer is provided with the PWM modulation power source, is provided with high-voltage rectification silicon stack between the secondary side of transformer and the auxiliary main circuit.
This voltage source also comprises by two groups measures the feedback circuit that partial pressure sensor is formed, the output of described auxiliary main circuit is connected with test product valve, the input of described two groups of measurement partial pressure sensors is connected to the measurement output of charging capacitor set on test product valve and the auxiliary main circuit, and the output of two groups of measurement partial pressure sensors feeds back to the control end of described PWM modulation power source.
Described PWM modulation power source is the two PWM modulation power sources of the controlled AC/DC-DC/AC of three-phase.
High voltage direct current converter valve operation test of the present invention adopts the PWM modulation power source with the low-pressure side of voltage source, the test voltage wide ranges, and particularly the low-voltage test characteristic is good; The voltage source overall loss is low, and power supply capacity requires little, and power-supply system only needs the complementary testing return loss, requires little to power system capacity; And use high voltage silicon stack to carry out rectification in the on-load tap-changing transformer high-pressure side, and control is simple, and equipment cost is low, and electric current is very little, need not consider the extra type of cooling; Greatly reduce the equipment cost and the operating cost of total system.
The starting of voltage source can reach the soft starting mode that boosts by set speed linearity by control PWM modulation power source, and according to the measurement data that feedback circuit feeds back, different electric pressure test requirements documents are satisfied in control of test voltage automated closed-loop or manually control.This voltage source can realize that low pressure is adjustable continuously from 0-660V, high pressure 1-60kV, has the voltage-regulation wide ranges, response speed is fast, reliable and stable characteristics.
Compare with the commutating circuit that transformer and thyristor are formed; this voltage source has realized that pressure regulation, rectification separate with the auxiliary resonance circuit; make control and protection system modularization; the dividing potential drop reponse system can be at any time the monitoring circuit equipment state, improved the fail safe and the safeguard measure of operational outfit greatly.The design of modular loop can fast and safely be withdrawed from respectively when the operation troubles state of test loop in order, has protected the safety of equipment effectively.
Description of drawings
Fig. 1 is the structural representation of voltage source of the present invention.
Fig. 2 is the voltage simulation waveform of the big voltage source of the present invention.
Embodiment
Below in conjunction with specific embodiment the present invention is done further introduction.
Be illustrated in figure 1 as the structural representation of high voltage direct current converter valve operation test of the present invention with voltage source, as seen from the figure, this voltage source comprises the controlled PWM power supply of three-phase, transformer, high-voltage rectification silicon stack and auxiliary main circuit: the controlled PWM power supply of three-phase is set between the primary side of transformer and the power distribution network, between the secondary side of transformer and the auxiliary main circuit high-voltage rectification silicon stack is set, the output of auxiliary main circuit connects test product valve Vt and feedback circuit.
Feedback circuit is measured partial pressure sensor by two groups and is formed, the input of two groups of measurement partial pressure sensors is connected to the measurement output of charging capacitor set on test product valve and the auxiliary main circuit, the output of measuring partial pressure sensor feeds back to the control end of described PWM modulation power source, respectively the Voltage Feedback of test product valve and charging capacitor is arrived the control section of PWM modulation power source, be illustrated in figure 2 as the voltage simulation waveform of the big voltage source of the present invention, wherein, thick line shows is voltage on the test product valve, and that fine rule shows is C
LLast voltage, what black patch showed is electric current.
The controlled PWM power supply of three-phase in the present embodiment adopts the two PWM modulation of AC/DC DC/AC inverter, the test voltage wide ranges, and particularly the low-voltage test characteristic is good; Transformer adopting 0.66/55.0KV on-load voltage regulation voltage source transformer.Auxiliary main circuit comprises between the positive pole, cathode output end of high-voltage rectification silicon stack and is serially connected with protective resistance R, charging capacitor CL successively, is serially connected with the second auxiliary valve D between charging capacitor CL positive pole and the negative pole successively
A2, resonant inductance Ls, the 3rd auxiliary valve D
A3, commutating inductance Lc, behind tandem electric inductance Lt and the test product valve Vt, constitute the through-flow loop of test product valve Vt; The 3rd auxiliary valve D
A3Oppositely and be connected to the 4th auxiliary valve D
A4Resonant inductance Ls and the 3rd auxiliary valve D
A3Common node and the negative pole of charging capacitor CL between be serially connected with oscillating capacitor Cs, the second auxiliary valve D
A2And be serially connected with the second auxiliary valve D between the negative pole of the common node of resonant inductance Ls and charging capacitor CL
A5
High voltage direct current converter valve operation test of the present invention is as follows with the operation principle of voltage source: power distribution network is to being connected to the controlled PWM power supply of three-phase between the step-up transformer, but at first trigger control control inverter commutating circuit, the value of linear regulation output voltage according to control timing.By high-voltage rectification silicon stack ac voltage rectifier after output dc voltage, promptly to electric capacity
Charging.Carve in due course, trigger second auxiliary valve
, by
To
Charging obtains the required high voltage of test.Trigger the 3rd auxiliary valve D
A3, provide test required high pressure to test product valve Vt, finish the control procedure that voltage is provided to test product valve Vt.
After test product valve Vt triggering and conducting, flow through big electric current by cooperating with current source, trigger D once more
A3Valve, C
sTo the test product valve discharge, provide the di/dt when thyristor turn-offs in the test product valve, at this moment
Voltage becomes oppositely, after test product valve provides reverse recovery voltage, triggers
, make
Voltage is just being become by negative, and then triggers
, to
Replenish loss of energy.So far electric current and the voltage of finishing a complete cycle cooperate.
Voltage source of the present invention is compared with the method that adopts thyristor to carry out rectification, and control is simple, and the voltage source overall loss is low, and power supply capacity requires little, and power-supply system only needs the complementary testing return loss, requires little to power system capacity; And using high voltage silicon stack to carry out rectification in the on-load tap-changing transformer high-pressure side, electric current is very little, need not consider the extra type of cooling.
The experimental rig that the present invention adopts PWM modulation power source and silicon stack rectification to cooperate, cooperate the resonant tank of forming by CL, Ls, Cs simultaneously, regulation voltage is to set value fast, simultaneously also can carry out complementary energy to Cs fast, this response speed and test accuracy are that converter transformer cooperates the rectification circuit institute of thyristor inaccessiable.Simultaneously, adopt the silicon stack rectification, greatly reduce purchase cost from the processing of the device cost and the type of cooling, and the loss of entire system is lower, less to the electric power system influence of 10kV.