CN1560981A

CN1560981A - Dynamic compensator for voltage down and surge

Info

Publication number: CN1560981A
Application number: CNA2004100084624A
Authority: CN
Inventors: 李国杰; 孙元章
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2004-03-12
Filing date: 2004-03-12
Publication date: 2005-01-05
Anticipated expiration: 2024-03-12
Also published as: CN100347927C

Abstract

A voltage slump and surge dynamic compensator characterizes that a test and control circuit with a mciroprocessor as its core enables the sinusoidal voltage output by an inverter to be directly connected in series with the power supply voltage during slumps and surges to compensate the necessary voltage and not influence the load voltage. It utilizes the voltage left by the system in slump and adds it to the output voltage of the inverter so the load gets a stable operating voltage and it crossly charges the DC capacitor for half period.

Description

Voltage is subside the surge dynamic compensator

Technical field

Voltage is subside the surge dynamic compensator and is belonged to Electrical Power System Dynamic voltage compensator technical field.

Background technology

Developed country is very high to the requirement of quality of power supply level, power quality problem not only can bring very big economic loss to industrial quarters, cause production cost to increase as stopping work and restarting, the damage equipment that is quick on the draw, scrap semi-finished product, reduce product quality, cause marketing difficulty and the infringement corporate image and and user's good commercial relations etc., and bring harm can for the equipment of important electricity consumption such as medical treatment department, cause serious production and interruption of service, EPRI-Electric Power Research Institute (EPRI) studies show that, power quality problem causes U.S.'s industry in data every year, on material and the productivity with a toll of 30,000,000,000 dollars (Electric PowerResearch Institute, 1999), in Singapore, each voltage instantaneous descends all can cause the economic loss that surpasses 1,000,000 Singapore dollars; Along with developing rapidly of China's high-technology industry, requirement to quality of power supply level is also more and more higher, voltage subside with surge be wherein subject matter, voltage is subside the quality of voltage problem that not only can cause electric power system with surge, the also trouble free service of entail dangers to power consumption equipment, electric power system fault, large-size machine starts, subcircuits short circuit etc. can cause that all voltage subsides, voltage surge is by lightning, connecting electric power system and other reasons causes overvoltage to cause, large-size machine and air conditioner are that big voltage surge produces the source, though it is short that voltage was subside with the surge time, but it can cause the interruption or the shut-down of industrial process, and cause industrial process downtime be far longer than voltage and subside itself with the surge accident time, therefore the loss that is caused is very big, the feature that voltage is subside is that supply voltage drops to 10% to 90% normal voltage value suddenly and continues 0.5 to 50 cycle, the feature of voltage surge is that supply voltage rises to 110% to 180% normal voltage value suddenly and continues 0.5 to 50 cycle, overwhelming majority voltage is subside and surge, its change in voltage amplitude in 50%, and the duration be no more than 500 milliseconds;

Traditional method, can not address these problems as voltage regulator and surge suppressor, though and the UPS device can address these problems, but its cost and operating cost are all extremely expensive, in order to address the above problem, dynamic voltage compensator has been carried out research both at home and abroad, the inverter of voltage dynamic compensator is every both at home and abroad at present mainly constitutes the full-bridge type structure by 4 groups of IGBT mutually, from design, can be divided into two big classes:

1. injection transformer mode

The sinusoidal voltage of inversion is connected in series to circuit by the transformer that injects, and charges to dc capacitor with transformer, or waits energy storage with flywheel;

2. there is not the injection transformer mode

Need to charge to dc capacitor with storage battery, super storage capacitor or with transformer;

The subject matter of its existence:

1. only solve voltage and subside problem;

2. for dynamic voltage compensator, IGBT is most important element, and price is not cheap yet, and power is big more, and IGBT is just expensive more, 4 groups of shared cost height of IGBT;

3. the transformer capacity of Zhu Ruing is relevant with load, and load is big more, and transformer capacity is just big more, and volume and the cost impact to whole device is very big like this, and it is suitable for middle and high volt circuit.For low-voltage circuit, not too economical and practical, and also have problem such as transformer pressure drop;

4. there is not injection transformer if come energy storage with storage battery, its capacity usage ratio is extremely low, and problems such as maintenance, environmental protection are arranged, in general, battery applications is in the design of dozens of minutes or several hours, and the multiple discharge of utmost point short time can influence its life-span, comes energy storage all very expensive with super storage capacitor or flywheel, no injection transformer then needs very big capacity if come energy storage with dc capacitor; If will use the least possible direct current capacity, then the capacity of charging transformer must be relevant with load capacity, so just makes the volume of whole device and cost increase;

Apply for and disclose the dynamic series voltage compensator and the dynamic series voltage compensation method of the Singapore Power Ltd of (publication number is 1353880) in June, 2002 to China State Intellectual Property Office in April, 2000, subside (rapid drawdown) problem and design at voltage, use batteries to store energy, just not saying the maintenance issues of its storage battery, only the capacity usage ratio of its storage battery is with regard to very low (being lower than 2%), thereby also increased cost greatly, inverter is made of 4 groups of IGBT of H type, has also increased cost.

Summary of the invention

The object of the present invention is to provide a kind of voltage to subside the surge dynamic compensator;

It is directly to be connected in series to (as 380 volts) in the low voltage electric network that the voltage that the present invention proposes is subside the surge dynamic compensator, both solve in the electric power system alternating voltage and subside (moment decline) problem, solved the problem of voltage surge (moment rising) again, when line voltage is subside with surge, its inverter is exported corresponding sinusoidal voltage and directly is injected into and compensates required voltage in the electrical network, because most voltages are subside and surge, its voltage amplitude is in 50%, and the duration is no more than 500 milliseconds, therefore, the remaining voltage more than 50% of system intersects charging to the dc capacitor of energy storage when utilizing voltage to subside, make that required energy storage direct current capacity is minimum, by increasing the energy that rises when a discharge loop absorbs voltage surge; In the design, both there be not the injection transformer of volume heaviness, do not need charging transformer again, inverter is made of 2 groups of IGBT of full control semi-bridge type, reduced cost, the controllable silicon that utilizes of its uniqueness is controlled the design of charge circuit, makes charge circuit quick charge and simplification;

The invention is characterized in:

It subsides the surge dynamic compensator by three single-phase voltages forms, and respectively contains:

Measure and control circuit, comprise:

Microprocessor;

Programmable timer, its timing signal input end links to each other with the corresponding output end of described microprocessor;

Logical AND or door, its two inputs respectively with the insulated door gridistor of the pulse-width modulation PWM signal output part of described programmable timer, described microprocessor, i.e. IGBT, the block signal output links to each other;

The supply voltage instrument transformer of mutual serial connection, i.e. PT, and filter circuit, the input of described supply voltage instrument transformer links to each other with supply voltage, and the output of described filter circuit links to each other with the supply voltage measuring-signal input of described microprocessor;

The load current instrument transformer of mutual serial connection, i.e. CT, and filter circuit, the input of described load current instrument transformer is a load current signal, the output of described filter circuit links to each other with the load current measuring-signal input of described microprocessor;

Single-phase voltage is subside the surge dynamic compensator, contains:

Silicon controlled main rectifier is made of two controllable silicon inverse parallels, and it and load are serially connected with in the electric power loop jointly, and its control end links to each other with the silicon controlled main rectifier control signal output ends of described microprocessor;

The charging controllable silicon is formed by two controllable silicon forward serial connections, and their tie point links to each other with the other end of power supply; Each silicon controlled control end links to each other with the charging SCR control signal output part of described microprocessor respectively;

Discharge paths is formed by discharge resistance, the discharge switch serial connection that is controlled by described microprocessor;

The energy storage branch road is formed by two storage capacitors serial connection, their tie point and silicon controlled main rectifier is connected with power supply that is continuous;

Inverter, by two insulated door grid thyristors, be IGBT, serial connection forms, be connected in series filter inductance and electric capacity successively between the tie point of the tie point of above-mentioned two inverters and two storage capacitors, the tie point between this filter inductance and the filter capacitor links to each other with that contact that silicon controlled main rectifier links to each other with load through the normally opened contact of a relay or contactor; Described inverter is while and energy storage branch road, discharge paths and the parallel connection of charging controllable silicon; The control end of each insulated door grid thyristor links to each other with the control IGBT signal output part of above-mentioned logical AND or door.

Between described each silicon controlled main rectifier and power source loads, respectively be connected in series an isolating switch, between power supply and load, also following a by-pass switch.

The present invention does not use injection transformer, directly be connected on i.e. 380 volt of one side of voltage low pressure, under operate as normal, power to the load by controllable silicon, the efficient height, and when voltage is subside surge, can protect power consumption equipment, it has save big capacity charging transformer, by the charging controllable silicon to the control of charging of the dc capacitor of energy storage; It comes energy storage with direct current capacity seldom, and the dc capacitor of energy storage is divided into positive and negative two groups, and one group provides energy to the inverter time spent, and another organizes charging, and each group continuous discharge is half AC network cycle; It has also save half number of I GBT thyristor.

Description of drawings

Fig. 1. single-phase voltage is subside surge dynamic compensator schematic block circuit diagram.

Fig. 2. measure and the control circuit theory diagram.

Fig. 3. the voltage of single-phase zone by-pass switch is subside surge dynamic compensator schematic block circuit diagram.

Fig. 4. series compensation schematic diagram when voltage is subside.

Fig. 5. series compensation schematic diagram during voltage surge.

Embodiment

Subside the design principle figure of surge dynamic compensator 15 in the empty frame of Fig. 1 for single-phase voltage, three-phase can by independently three single-phasely constitute, energy required between the amortization period is provided by a spot of dc capacitor 6,7, not only environmental protection but also low cost, designed dynamic compensator can solve the problem of subsideing, and can solve the voltage surge problem again;

Shown in the empty frame 15 of Fig. 1, voltage is subside surge dynamic compensator 15 by silicon controlled main rectifier 1, inverter 2,3, charging controllable silicon 4,5, dc capacitor 6,7, ac filter inductance 8, ac filter electric capacity 9, relay or contactor 10, discharge resistance 11, controllable silicon discharge switch 12, and measuring and control circuit 16 (see figure 2)s formation, below introduce each part in detail:

1 is one group of antiparallel silicon controlled main rectifier (during low capacity, also can consider the IGBT anti-series is come to use together), and during operate as normal, power supply 13 voltages offer load by them;

2 and 3 is IGBTs (insulated door gridistors), and they have formed inverter, and power supply 13 voltage instantaneous change when surpassing set point, and according to required voltage, inverter is exported corresponding pulse-width modulation PWM signal;

4 and 5 is charging controllable silicons, is used for controlling the charging to dc capacitor 6,7;

6 and 7 is dc capacitors, is used for storage power so that when compensation is required, even between the amortization period, also can obtain charging every half period;

8 and 9 is respectively ac filter inductance and electric capacity, and the pwm signal of inverter 2 and 3 outputs obtains sinusoidal voltage during compensation after 8 and 9, and this sinusoidal voltage is connected in series to and compensates required voltage in the electrical network, makes load 14 voltages not be subjected to the influence of power supply 13 voltages;

The 10th, relay or contactor are closed soon after powering on;

11 and 12 discharge resistance and switches (switch is MOSFET or IGBT) when being voltage surge respectively;

13 represent power supply, and the L that links to each other with power supply represents live wire, and N represents center line;

14 represent load;

Goodbye Fig. 2～5:

When powering on, by measuring and control circuit 16 control charging controllable silicons 4,5 come dc capacitor 6,7 charge, when dc capacitor 6, after 7 voltage is full of, send signal by measurement and control circuit 16 and come closing relay or contactor 10, during operate as normal, power supply 13 voltages offer load 14 by silicon controlled main rectifier 1, measure and control circuit 16 real-time monitoring power supply 13 voltages, when detecting power supply 13 voltages above set point, disconnect silicon controlled main rectifier 1, measurement and control circuit 16 send control signal makes inverter 2, the corresponding pwm signal of 3 outputs, pwm signal obtains required sinusoidal voltage behind ac filter inductance 8 and electric capacity 9, this sinusoidal voltage and power supply 13 voltages are superimposed, make load obtain normal voltage, the series compensation schematic diagram was seen Fig. 4 when voltage was subside with surge, 5;

In actual applications, design as shown in Figure 1 can directly be connected in series in the power supply of load, also can be connected in series to together in the power supply of load to maintain easily, to overhaul with by-pass switch 17, isolating switch 18,19, as shown in Figure 3, by-pass switch and the isolating switch with three-phase is applied in the three-phase system.

Claims

1. voltage is subside the surge dynamic compensator, it is characterized in that: it contains three single-phase voltages and subsides the surge dynamic compensator, respectively contains:

Measure and control circuit, comprise:

Microprocessor;

Single-phase voltage is subside the surge dynamic compensator, contains:

2. voltage according to claim 1 is subside the surge dynamic compensator, it is characterized in that: respectively be connected in series an isolating switch between described each silicon controlled main rectifier and power source loads, also follow a by-pass switch between power supply and load.