CN102593777A - Design method of direct-current ice melting device with special converter transformer - Google Patents

Abstract

The invention relates to a design method of a direct-current ice melting device with a special converter transformer. The method comprises the following steps of 1) determining a covered line of the ice melting device; 2) pre-selecting a wire ice melting current; 3) determining the maximum allowable current of the lead; 4) calculating the direct current voltage drop and power under the preselected ice melting current; 5) determining rated parameters of the ice melting device; 6) calculating an ideal no-load direct current voltage; 7) calculating the rated voltage of the valve side of the commutation reactor; 8) calculating the rated voltage of the commutation reactor side of the converter transformer; 9) calculating rated current of an alternating current side of the converter; 10) calculating inductance of the commutation reactor; 11) calculating the rated capacity of the converter transformer; 12) calculating the inductive reactance of the converter transformer; 13) determining rated capacity and current of a TCR branch circuit or a TSR branch circuit; 14) determining the total inductive reactance value of the TCR branch or the TSR branch; 15) determining that inductance value needs to be increased for the TCR branch or the TSR branch; 16) determining a zero power loop inductance; 17) determining a zero-power minimum allowable current; 18) and designing an alternating current filter.

Description

A Design Method of DC Ice-melting Device with Special Converter Transformer

technical field

The invention relates to a design method of a DC deicing device with a special converter transformer, in particular to a design method involving a comprehensive consideration of DC deicing and its equivalent test, a thyristor controlled reactor (TCR) or a thyristor switching reactor (TSR) It belongs to the innovative technology of DC ice melting and static var compensation application of high-voltage and ultra-high voltage power grid transmission lines.

Background technique

Icing of transmission lines in winter seriously threatens the safe operation of the power system. Due to the increased ice load on the conductors, it will cause certain mechanical damage to the conductors, iron towers and fittings. When the ice is severe, the wires will be broken and the towers will fall, resulting in large-scale power outages and great losses to the national economy.

As the global climate continues to deteriorate, the damage caused by ice disasters to transmission lines is becoming more and more serious. Especially the ice disaster in early 2008 caused huge losses to my country's power grid.

Several ideas for research on ice melting at home and abroad are as follows: convert electrical energy into heat energy to melt ice; deicing.

Since the 1970s, my country has been using the AC short-circuit method to melt ice on lines below 220kV, which has played a certain role in preventing ice disasters. Due to the high heat required for AC melting and the reactance of the AC line, the capacity of the ice-melting power supply required for 220kV and below lines is 5-10 times the actual ice-melting power of the line; for ultra-high voltage and ultra-high voltage above 500kV The ice-melting power supply capacity required for AC transmission lines to melt ice is 10-20 times the actual line ice-melting power. There is often the problem that the capacity of the ice-melting power supply is far insufficient when implementing AC current short-circuit ice melting. Therefore, for 500kV or higher voltage transmission lines, it is not feasible to use an AC short circuit ice melting solution because it is difficult to find a melting ice power supply that meets the requirements.

Due to the limitations of the AC short-circuit ice melting method, the possibility of DC ice melting and the development of DC ice melting devices have been discussed internationally since the 1980s. After the North American ice storm disaster in 1998, Hydro-Québec and AREVA jointly developed a DC ice-melting device, which was installed in the Lévis substation in Quebec and completed on-site commissioning in 2008. But so far, the device has not been used to actually melt ice.

After the ice disaster in 2008, Chinese power science and technology workers independently carried out the research and development of DC ice-melting technology and devices, and successfully developed a high-power DC ice-melting device with completely independent intellectual property rights, mainly including dedicated converter transformers and non-specialized converter transformers. Various types such as converter transformers and vehicle-mounted mobile types have been promoted and applied throughout the country.

In January 2011, due to the continuous low-temperature rain and snow freezing weather, power transmission and transformation facilities in most areas of Guizhou, northern Guangxi, northern Guangdong, and northeastern Yunnan, within the power supply area of China Southern Power Grid, were in danger of being iced one after another. As a result, 1414 10kV and above lines and 70 35kV and above substations were out of service. The first ice disaster in 2011 was another severe ice disaster encountered by China Southern Power Grid after 2008. However, compared with 2008 when multiple lines were disconnected and towers collapsed, the 500kV main grid was severely damaged, multiple power grids were disconnected or operated in isolation, and a large number of supply loads were reduced, there were no tower collapses of 220kV and above lines during the ice disaster. , No power outage accidents occurred in cities at the county level or above, ensuring the safe and stable operation of the power grid and the normal supply of power. During the ice disaster in 2011, the 19 sets of DC ice-melting devices installed by China Southern Power Grid were fully tested for the first time and played a huge role. They melted ice for 110kV and above lines 227 times, including more than 40 times for 500kV lines.

In view of the actual application effect of the DC deicing device, my country's power grid enterprises have carried out a new round of large-scale promotion and application since 2011.

In view of the fact that the DC ice melting device is not used for ice melting for a long time each year, in practical applications, it generally also has the function of a static var compensation device, and no complete design method has yet been proposed.

Contents of the invention

The purpose of the present invention is to consider the above problems and provide a design method for a DC deicing device with a dedicated converter transformer that comprehensively considers functions such as DC deicing and its equivalent test, thyristor control reactor or thyristor switching reactor. The invention is convenient and practical.

The technical solution of the present invention is: a design method of a DC deicing device with a dedicated converter transformer, the DC deicing device with a dedicated converter transformer has a static reactive power compensation function, including one or two dedicated converter transformers T, one or two sets of reactors L1a, L1b, L1c, one or two sets of six-pulse converter R, one or two sets of reactors L2a, L2b, L2c, knife switches S1, S2, S3, S4, Control and protection system CP, AC filter bank F, reactors L1a, L1b, L1c are commutation reactors in DC deicing mode, and part of thyristor control reactor TCR or thyristor switching reactor TSR in reactive power compensation mode , the reactors L2a, L2b, L2c are three-phase parallel or one phase is a smoothing reactor in the DC ice melting mode, and it is a part of the thyristor controlled reactor TCR or the thyristor switching reactor TSR in the reactive power compensation mode; In the ice melting mode, the AC side of the converter R is connected to the dedicated converter transformer T through the reactors L1a, L1b, L1c, and the DC side of the converter R is connected to the knife switches S1, S2, S3, S4 is connected, and the dedicated converter transformer T is connected to the AC system through the isolation switch K and the circuit breaker QF; The valves V1 and V4 in the converter R are connected in antiparallel to the reactors L2a and L1c in series and then connected between the phases b and c of the low-voltage side of the dedicated converter transformer T. The valves V5 and V2 in the converter R are connected in antiparallel to the reactors L1a and L1a. L2b is connected in series between phases a and c of the low-voltage side of the dedicated converter transformer T, and the valves V3 and V6 in the converter R are connected in anti-parallel and connected in series with the reactors L2c and L1b, and then connected to the low-voltage side a and c of the dedicated converter transformer T. Between phase b, the dedicated converter transformer T is connected to the AC system through the isolation switch K and the circuit breaker QF; the filter F is connected to the power supply side of the converter transformer T through the isolation switch K1 and the circuit breaker QF1; the switch S1, S2, S3 , K, K1, position signals of circuit breakers QF, QF1, converter valve side current signals Iva, Ivb, Ivc, grid side currents Ia, Ib, Ic, DC side current signals Idp, Idn, Idgnd and DC side voltage signals The monitoring signals of Udp, Udn and converter R are connected to the control and protection system CP; the control and protection system CP issues the opening and closing commands of the knife switch and circuit breaker, and sends out the control and trigger commands of the converter R;

Among them, the design method of the DC ice-melting device with special converter transformer with static var compensation function includes the following steps:

1) Determine the line range covered by the DC deicing device;

2) Pre-select the ice-melting current of each wire;

3) Determine the maximum allowable current of each wire;

4) Calculate the DC voltage drop and DC power of each line when the ice-melting current is preselected;

5) Determine the rated parameters of the DC deicing device;

6) Calculate the ideal no-load DC voltage of the converter at the rated firing angle;

7) Calculate the rated AC voltage on the valve side of the commutation reactor;

8) Calculate the rated AC voltage on the commutation reactor side of the special converter transformer;

9) Calculate the rated current of the AC side of the converter;

10) Calculate the inductance value of the commutation reactor;

11) Calculate the rated capacity of the dedicated converter transformer;

12) Calculate the inductive reactance of the dedicated converter transformer;

13) Determine the rated current and rated capacity of the thyristor controlled reactor TCR or thyristor switching reactor TSR branch;

14) Determine the total inductance value of the thyristor controlled reactor TCR or thyristor switching reactor TSR branch;

15) Determine the inductance value of the thyristor control reactor TCR or the thyristor switching reactor TSR branch in addition to the commutation reactor;

16) Determine the loop inductance in the zero power mode of the DC deicing device;

17) Determine the minimum allowable current in the zero power mode of the DC deicing device;

18) Design AC filter.

The above steps 1) determine the method of covering the line range of the DC deicing device as follows:

Determine the line that needs to use the device for ice melting according to the location where the DC ice melting device is used, including individual lines that may be connected in series through substations for ice melting in special cases. According to the type of wires of each line, the DC resistance value of each wire of the line at 20°C can be obtained.

The method of the above step 2) pre-selecting the ice-melting current of each wire is as follows:

Calculate the minimum ice-melting current of each line under typical icing conditions according to the Burgersdorff formula, and take 1.1 times of the calculated value as the pre-selected ice-melting current of each conductor, that is

I _dpr ＝1.1I _de·min (1)

In the formula, I _dpr - the pre-selected ice-melting current of each wire, kA; I _{de · min} - the minimum ice-melting current of the line, kA.

The above step 4) calculates the DC voltage drop and DC power of each line at the time of pre-selecting the ice-melting current as follows:

According to the method of connecting two-phase wires in series, that is, "one to one return" method, or "1-1" method, calculate the DC voltage drop and DC power of each line at the time of pre-selecting the ice-melting current, which is the following formula

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}}\mathrm{<span\; class="notranslate">\; RL</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="dN"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">dN</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; RL</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _dpr - the DC voltage drop of each wire when the ice is melted in the "one-to-one-return" method, kV; R-the DC resistance of the ice-melting line at 20°C, Ω/km; L-the length of the line, km; P _de -the wires The DC power when the ice is melted in the "one-to-one-back" method, MW.

The method for determining the rated current parameters of the DC deicing device in the above step 5) is as follows:

Determine the rated DC power, DC current and DC voltage of the DC ice-melting device based on the maximum value calculated by formulas (1) and (2), and the rated DC power, rated DC current and rated DC voltage of the DC ice-melting device are greater than or equal to The maximum value calculated by formulas (1) and (2), and the rated DC current is less than the maximum value of the maximum allowable current I _max of the wire, that is

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span>\\ \mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span>\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _dN - rated DC voltage of DC ice melting device, kV; I _dN - rated DC current of DC ice melting device, kA; P _dN - rated DC power of DC ice melting device, MW; i - use the DC ice melting device Line number for ice melting.

The method for calculating the ideal no-load DC voltage of the converter at the rated firing angle in the above step 6) is as follows:

The ideal no-load DC voltage of the converter at the rated firing angle is calculated by the following formula, namely

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dio\; N</span>}}<span\; class="notranslate">\; =</span>\frac{\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}{\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; xn</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; rn</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

U_K％为系统阻抗电压U_S％、换流变阻抗电压U_T％与换相电抗器阻抗电压U_CR％之和，设计中可忽略系统阻抗电压；d_rn-直流阻性压降标幺值，取0；V_T-换流器正向导通压降，取0。In the formula, U _dioN - the ideal no-load DC voltage at the rated trigger angle, kV; α _N - the rated trigger trigger angle, the trigger angle corresponding to the rated DC voltage and DC power conditions, °, take 5°-20°; n - the number of six-pulse converters, 1 for six-pulse converters, and 2 for twelve-pulse converters formed in series with double bridges; d _xn - per unit value of DC inductive voltage drop,

U _K ％ is the sum of system impedance voltage U _S ％, commutation transformer impedance voltage U _T ％ and commutation reactor impedance voltage U _CR ％, the system impedance voltage can be ignored in the design; d _rn - DC resistive voltage drop per unit Value, take 0; V _T -converter forward conduction voltage drop, take 0.

The method of calculating the rated AC voltage on the valve side of the commutation reactor in the above step 7) is as follows:

The rated AC voltage on the valve side of the commutation reactor is calculated according to the following formula, namely

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; di</span>}\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; N</span>}}}{\mathrm{<span\; class="notranslate">\; 1.35</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _VN is the AC voltage on the valve side of the commutation reactor, kV.

The method for calculating the rated AC voltage on the commutation reactor side of the special converter transformer in step 8) above is as follows:

The rated AC voltage on the commutation reactor side of the special converter transformer is calculated according to the following formula, namely

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; \%</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _2N is the AC voltage on the commutation reactor side of the special converter transformer, kV; U _CR % is the impedance voltage of the commutation reactor, which is 0-0.06, and when it is 0, the commutation reactor is not used, and the commutation reactor The converter is directly connected to the output side of the dedicated converter transformer.

The method for calculating the rated current of the AC side of the converter in the above step 9) is as follows:

The rated current on the AC side of the converter is calculated using the following formula, namely

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.816</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

In the formula, I _VN - the rated valve side current of the converter, kA.

The method for calculating the inductance value of the commutation reactor in the above step 10) is as follows:

The inductance value of the commutation reactor is calculated by the following formula

${\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="u\; CR\; \%"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">u</figure-callout></span><figure-callout\; id="2"\; label="u\; CR\; \%"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; \%</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;f</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

In the formula, L _CR - commutation reactor inductance value, H; U _CR ％ - commutation reactor impedance voltage;

The method for calculating the rated capacity of the special converter transformer in the above step 11) is as follows:

For the six-pulse converter, one three-phase transformer is used for the dedicated converter transformer, and for the twelve-pulse converter, two three-phase transformers are used for the dedicated converter transformer, and the rated capacity of a single unit is calculated using the following formula, namely

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

In the formula, S _N - rated capacity of special converter transformer, MVA; K - harmonic power multiple, take 0.08-0.12;

The method for calculating the inductance of the special converter transformer in the above step 12) is as follows:

The inductive reactance of the dedicated converter transformer is calculated using the following formula

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

In the formula, X _T - special converter transformer impedance, Ω; U _T % - special converter transformer impedance voltage, take 0.08-0.12, take the larger value when there is no commutation reactor, and take the smaller value when there is a commutation reactor;

The method for determining the branch circuit capacity and rated current of the thyristor-controlled reactor TCR or thyristor switching reactor TSR in the above step 13) is as follows:

When the DC deicing device is converted into a thyristor-controlled reactor TCR or a thyristor-switched reactor TSR, the branch capacity of the thyristor-controlled reactor TCR or thyristor-switched reactor TSR is determined by the capacity of the dedicated converter transformer, so

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; SVCN</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}\\ {\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; SVCN</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; SVCN</span>}}}{\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; an</span>}}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

In the formula, Q _SVCN - rated capacity of thyristor controlled reactor TCR or thyristor switched reactor TSR, MVAr; I _SVC N - rated current of thyristor controlled reactor TCR or thyristor switched reactor TSR branch, kA;

The method for determining the total inductance value of the thyristor-controlled reactor TCR or thyristor switching reactor TSR branch in the above step 14) is as follows:

The total inductance value of thyristor controlled reactor TCR or thyristor switching reactor TSR branch is calculated by the following formula, namely

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; SVC</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="N"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">N</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 9</span>}{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; )</span>$

In the formula, X _SVCY - thyristor controlled reactor TCR or thyristor switching reactor TSR branch reactance value, Ω.

The above step 15) to determine the thyristor control reactor TCR or thyristor switching reactor TSR branch in addition to the commutation reactor to increase the inductance of the reactor is as follows:

For the thyristor controlled reactor TCR or thyristor switched reactor TSR branch, the inductance value of the reactor needs to be increased according to the following formula, namely

In the formula, L _{TCR Δ} - the inductance value of the thyristor-controlled reactor TCR branch increased reactor, H; α _N - the delayed trigger angle of the thyristor-controlled reactor TCR rated capacity, °, 95-104°; L _TSR·Δ - thyristor switching reactor TSR branch increases the inductance value of the reactor, H.

The method for determining the loop inductance in the above step 16) in the zero power mode of the DC deicing device is as follows:

For twelve-pulse, use thyristor-controlled reactor TCR or thyristor-switched reactor TSR branch to increase the three-phase parallel connection of the reactor as a smoothing reactor, and the inductance of the entire loop in the zero-power mode of the DC deicing device is calculated according to the following formula ,Right now

For the six-pulse, use a thyristor-controlled reactor TCR or a thyristor-switched reactor TSR branch to add one phase of the reactor as a smoothing reactor, and the inductance of the entire loop in the zero-power mode of the DC deicing device is calculated according to the following formula, namely

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; dcs</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1.5</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="x\; T"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">x</figure-callout></span><figure-callout\; id="2"\; label="x\; T"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;f</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; TCR</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}}\\ {\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; dcs</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1.5</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="x\; T"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">x</figure-callout></span><figure-callout\; id="2"\; label="x\; T"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;f</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; TSR</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 15</span>}<span\; class="notranslate">\; )</span>$

In the formula, L _dcs - the loop inductance value of the DC deicing device in zero power mode, H;

The method of determining the minimum allowable current in the zero power mode of the above step 17) is as follows:

For the twelve-pulse DC ice-melting device, the minimum allowable current in zero power mode is calculated according to the following formula, namely

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; al</span>}\mathrm{<span\; class="notranslate">\; min</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; sr</span>}}\frac{\mathrm{<span\; class="notranslate">\; 0.023</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dio\; N</span>}}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; dcs</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 16</span>}<span\; class="notranslate">\; )</span>$

For the six-pulse DC deicing device, the minimum allowable current in zero power mode is calculated according to the following formula, namely

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; al</span>}\mathrm{<span\; class="notranslate">\; min</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; sr</span>}}\frac{\mathrm{<span\; class="notranslate">\; 0.0931</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dio\; N</span>}}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; dcs</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 17</span>}<span\; class="notranslate">\; )</span>$

In the formula, I _almin - the minimum allowable current of the DC ice melting circuit, kA; K _sr - the reliability factor to ensure that the current is not continuous during the zero power test, take 1.2-2.0;

Above-mentioned step 18) the method for designing AC filter is as follows:

The AC filter design is completed according to the harmonic and reactive power characteristics of the DC deicing device operating in zero power mode at rated current.

Compared with the prior art, the present invention provides a complete design of a DC deicing device with a dedicated converter transformer, which comprehensively considers the functions of DC deicing and its equivalent test, thyristor control reactor or thyristor switching reactor, etc. method. The invention is a convenient and practical design method of a DC ice-melting device with a special converter transformer.

Description of drawings

Figure 1 is a schematic diagram of a 12-pulse DC deicing device with a dedicated converter transformer.

Fig. 2 is a schematic diagram of a twelve-pulse DC deicing device with a special converter transformer converted to TCR or TSR operation.

Figure 3 is a schematic diagram of a six-pulse DC deicing device with a dedicated converter transformer.

Fig. 4 is a schematic diagram of a six-pulse DC deicing device with a dedicated converter transformer converted to TCR or TSR operation.

Detailed ways

Example 1:

The structural diagram of the 12-pulse DC ice-melting and reactive power compensation device with special converter transformer of the present invention is shown in Figures 1 and 2. In this embodiment, two special converter transformers T (one is Y/Y connection, the other is Y/Δ connection), two sets of reactors L1a, L1b, L1c, two sets of six-pulse converter R, two sets of reactors L2a, L2b, L2c, knife switches S1, S2, S3, S4 , control and protection system CP, AC filter bank F, reactors L1a, L1b, L1c are commutation reactors in DC ice melting mode, and are thyristor control reactor TCR or thyristor switching reactor TSR in reactive power compensation mode One part, the reactors L2a, L2b, L2c are all connected in parallel as smoothing reactors in the DC deicing mode, and are part of the thyristor controlled reactor TCR or the thyristor switching reactor TSR in the reactive power compensation mode; in the DC deicing mode In this mode, the AC side of two six-pulse converters R is connected to two dedicated converter transformers T through reactors L1a, L1b, L1c to form a twelve-pulse converter, and the DC side of two six-pulse converters R passes through The reactors L2a, L2b, L2c are connected to the switches S1, S2, S3, S4, and the two dedicated converter transformers T are connected to the AC system through the isolation switch K and the circuit breaker QF; in the reactive power compensation mode, the thyristor control In the reactor TCR or thyristor switching reactor TSR mode, the valves V1 and V4 in the six-pulse converter R are connected in anti-parallel and then connected in series with the reactors L2a and L1c, and then connected between phases b and c of the low-voltage side of the special converter transformer T , the valves V5 and V2 in the converter R are connected in anti-parallel and connected in series with the reactors L1a and L2b, and then connected between phases a and c on the low-voltage side of the dedicated converter transformer T, and the valves V3 and V6 in the converter R are connected in anti-parallel After connecting in series with reactors L2c and L1b, it is connected between phases a and b of the low-voltage side of the dedicated converter transformer T. The dedicated converter transformer T is connected to the AC system through the isolation switch K and circuit breaker QF; the filter F is connected through the isolation switch K1 and circuit breaker QF1 are connected to the power supply side of the converter transformer T; the position signals of the knife switches S1, S2, S3, K, K1 and circuit breakers QF, QF1 and the current signals Iva, Ivb, Ivc of the converter valve side and the grid side current Ia, Ib, Ic and the DC side current signals Idp, Idn, Idgnd and DC side voltage signals Udp, Udn and the monitoring signals of the converter R are connected to the control and protection system CP; Combining commands and issuing control and trigger commands for converter R. Among them, the design method of the DC ice-melting device with special converter transformer with static var compensation function includes the following steps:

1) Determine the range of lines covered by the DC deicing device

Determine the line that needs to use the device for ice melting according to the location where the DC ice melting device is used, including individual lines that may be connected in series through substations for ice melting in special cases. According to the type of wires of each line, the DC resistance value of each wire of the line at 20°C can be obtained.

2) Pre-select the ice-melting current of each wire

Calculate the minimum ice-melting current of each line under typical ice-covered conditions (for example: -5°C, wind speed 5m/s, ice thickness 10mm, and complete ice melting within 1 hour) according to the Burgersdorff formula, and take the calculated value 1.1 times is the pre-selected ice-melting current for each wire, that is

I _dpr ＝1.1I _de·min (1)

In the formula, I _dpr - the pre-selected ice-melting current of each wire, kA; I _{de · min} - the minimum ice-melting current of the line, kA.

3) Determine the maximum allowable current of each wire

Calculate the maximum allowable current I _max of each conductor according to the calculation method provided in Article 5.0.6 of the "Code for Design of 110kV-750kV Overhead Transmission Lines" in GB5045-2010. Calculation conditions: ambient temperature 10°C, wind speed 0.5 m/s, allowable temperature of the conductor 90°C, radiation coefficient 0.9, absorption coefficient 0.9, sunlight intensity 0.1W/cm ² .

4) Calculate the DC voltage drop and DC power of each line when the ice-melting current is pre-selected

According to the method of connecting two-phase wires in series, that is, "one to one return" method, or "1-1" method, calculate the DC voltage drop and DC power of each line at the time of pre-selecting the ice-melting current, which is the following formula

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}}\mathrm{<span\; class="notranslate">\; RL</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="I\; dN"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">I</figure-callout></span><figure-callout\; id="2"\; label="I\; dN"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}^{\mathrm{<span\; class="notranslate">dN</span>}}\mathrm{<span\; class="notranslate">\; RL</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _dpr - the DC voltage drop of each conductor when the ice is melted in the "one-to-one-return" method, kV; R-the DC resistance of the ice-melting line at 20°C, Ω/km; L-the length of the line, km; P _dc -each conductor The DC power when the ice is melted in the "one-to-one-back" method, MW.

5) Determine the rated current parameters of the DC ice melting device

Determine the rated DC power, DC current and DC voltage of the DC ice-melting device based on the maximum value calculated by formulas (1) and (2), and the rated DC power, rated DC current and rated DC voltage of the DC ice-melting device are greater than or equal to The maximum value calculated by formulas (1) and (2), and the rated DC current is less than the maximum value of the maximum allowable current I _max of the wire, that is

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span>\\ \mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span>\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _dN - rated DC voltage of DC ice melting device, kV; I _dN - rated DC current of DC ice melting device, kA; P _dN - rated DC power of DC ice melting device, MW; i - use the DC ice melting device Line number for ice melting.

6) Calculate the ideal no-load DC voltage of the converter at the rated firing angle

The ideal no-load DC voltage of the converter at the rated firing angle is calculated by the following formula, namely

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dio\; N</span>}}<span\; class="notranslate">\; =</span>\frac{\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}{\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; xn</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; rn</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

U_K％为系统阻抗电压U_S％、换流变阻抗电压U_T％与换相电抗器阻抗电压U_CR％之和，设计中可忽略系统阻抗电压；d_rn-直流阻性压降标幺值，取0；V_T-换流器正向导通压降，取0。In the formula, U _dioN - the ideal no-load DC voltage at the rated firing angle, kV; α _N - the rated firing angle, the firing angle corresponding to the rated DC voltage and DC power conditions, taking 5-20°; d _xn - DC per unit value of inductive voltage drop,

U _K ％ is the sum of system impedance voltage U _S ％, commutation transformer impedance voltage U _T ％ and commutation reactor impedance voltage U _CR ％, the system impedance voltage can be ignored in the design; d _rn - DC resistive voltage drop per unit Value, take 0; V _T -converter forward conduction voltage drop, take 0.

7) Calculate the rated AC voltage on the valve side of the commutation reactor

The rated AC voltage on the valve side of the commutation reactor is calculated according to the following formula, namely

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; di</span>}\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; N</span>}}}{\mathrm{<span\; class="notranslate">\; 1.35</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _VN is the AC voltage on the valve side of the commutation reactor, kV.

8) Calculate the rated AC voltage on the commutation reactor side of the special converter transformer

The rated AC voltage on the commutation reactor side of the special converter transformer is calculated according to the following formula, namely

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; \%</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _2N is the AC voltage on the commutation reactor side of the special converter transformer, kV; U _CR % is the impedance voltage of the commutation reactor, which is 0-0.06, and when it is 0, the commutation reactor is not used.

9) Calculate the rated current of the AC side of the converter

The rated current on the AC side of the converter is calculated using the following formula, namely

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.816</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

In the formula, I _VN - the rated valve side current of the converter, kA.

10) Calculate the inductance value of the commutation reactor

The inductance value of the commutation reactor is calculated by the following formula

${\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="u\; CR\; \%"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">u</figure-callout></span><figure-callout\; id="2"\; label="u\; CR\; \%"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; \%</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;f</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

In the formula, L _CR - commutation reactor inductance value, H; U _CR % - commutation reactor impedance voltage.

11) Calculate the rated capacity of the dedicated converter transformer

Two three-phase transformers are used for the dedicated converter transformer, and the rated capacity of a single transformer is calculated using the following formula, namely

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

In the formula, S _N - rated capacity of special converter transformer, MVA; K - harmonic power multiple, take 0.08-0.12.

12) Calculate the inductive reactance of the dedicated converter transformer

The inductive reactance of the dedicated converter transformer is calculated using the following formula

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

In the formula, X _T - special converter transformer impedance, Ω; U _T % - special converter transformer impedance voltage, take 0.08-0.12, take a larger value when there is no commutation reactor, and take a smaller value when there is a commutation reactor.

13) Determine the thyristor controlled reactor TCR or thyristor switching reactor TSR branch capacity and rated current

When the DC deicing device is converted into a thyristor-controlled reactor TCR or a thyristor-switched reactor TSR, the branch capacity of the thyristor-controlled reactor TCR or thyristor-switched reactor TSR is determined by the capacity of the dedicated converter transformer, so

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; SVCN</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}\\ {\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; SVCN</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; SVCN</span>}}}{\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; an</span>}}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

In the formula, Q _SVCN - rated capacity of thyristor controlled reactor TCR or thyristor switched reactor TSR, MVAr; I _SVCN - rated current of thyristor controlled reactor TCR or thyristor switched reactor TSR branch, kA.

14) Determine the total inductance value of the thyristor controlled reactor TCR or thyristor switching reactor TSR branch

The total inductance value of thyristor controlled reactor TCR or thyristor switching reactor TSR branch is calculated by the following formula, namely

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; SVC</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="N"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">N</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 9</span>}{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; )</span>$

In the formula, X _SVC·Y - thyristor controlled reactor TCR or thyristor switching reactor TSR branch reactance value, Ω.

15) Determine the inductance value of the thyristor control reactor TCR or the thyristor switching reactor TSR branch in addition to the commutation reactor;

For the thyristor controlled reactor TCR or thyristor switched reactor TSR branch, the inductance value of the reactor needs to be increased according to the following formula, namely

In the formula, L _{TCR Δ} - the inductance value of the thyristor-controlled reactor TCR branch increased reactor, H; α _N - the delayed trigger angle of the thyristor-controlled reactor TCR rated capacity, °, 95-104°; L _TSR·Δ - thyristor switching reactor TSR branch increases the inductance value of the reactor, H.

16) Determine the loop inductance of the DC ice melting device in zero power mode

For twelve-pulse, use thyristor-controlled reactor TCR or thyristor-switched reactor TSR branch to increase the three-phase parallel connection of the reactor as a smoothing reactor, and the inductance of the entire loop in the zero-power mode of the DC deicing device is calculated according to the following formula ,Right now

In the formula, L _dcs - the loop inductance value of the DC deicing device in zero power mode, H;

17) Determine the minimum allowable current in the zero power mode of the DC ice melting device

For the 12-pulse DC ice-melting device, the three-phase parallel connection in the reactor is used as the smoothing reactor, and the minimum allowable current in the zero-power mode is calculated according to the following formula, that is

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; al</span>}\mathrm{<span\; class="notranslate">\; min</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; sr</span>}}\frac{\mathrm{<span\; class="notranslate">\; 0.023</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dio\; N</span>}}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; dcs</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 15</span>}<span\; class="notranslate">\; )</span>$

In the formula, I _almin - the minimum allowable current of the DC ice melting circuit, kA; K _sr - the reliability factor to ensure that the current is not continuous during the zero power test, taking 1.2-2.0.

18) Design AC filter

The AC filter design is completed according to the harmonic and reactive power characteristics of the DC deicing device operating in zero power mode at rated current.

Example 2:

The structural diagram of the six-pulse DC deicing and reactive power compensation device with special converter transformer of the present invention is shown in Figures 3 and 4. In this embodiment, a special converter transformer T (Y/Δ connection) is included, and a set of Reactors L1a, L1b, L1c, a group of six-pulse converter R, a group of reactors L2a, L2b, L2c, knife switches S1, S2, S3, S4, control and protection system CP, AC filter group F, reactors L1a, L1b, and L1c are commutation reactors in DC ice-melting mode, and are part of thyristor-controlled reactor TCR or thyristor switching reactor TSR in reactive power compensation mode. Reactors L2a, L2b, and L2c are all in DC ice-melting mode. The next phase of the mode is a smoothing reactor, which is a part of the thyristor control reactor TCR or thyristor switching reactor TSR in the reactive power compensation mode; in the DC ice melting mode, the AC side of the six-pulse converter R passes through the reactor L1a, L1b, L1c are connected to the dedicated converter transformer T, the DC side of the six-pulse converter R is connected to the switch S1, S2, S3, S4 through the reactor L2a, L2b, L2c, and the dedicated converter transformer T is passed through the isolation switch K and circuit breaker QF are connected to the AC system; in reactive power compensation mode, that is, thyristor controlled reactor TCR or thyristor switching reactor TSR mode, valves V1 and V4 in six-pulse converter R are connected in antiparallel with The reactors L2a and L1c are connected in series between the low-voltage side b and c of the dedicated converter transformer T, and the valves V5 and V2 in the converter R are connected in antiparallel and connected in series with the reactors L1a and L2b and then connected to the dedicated converter transformer T Between phases a and c on the low-voltage side, the valves V3 and V6 in the converter R are connected in anti-parallel, connected in series with reactors L2c and L1b, and then connected to the dedicated converter transformer T between phases a and b on the low-voltage side, and the dedicated converter transformer T is isolated by The switch K and the circuit breaker QF are connected to the AC system; the filter F is connected to the power supply side of the converter transformer T through the isolation switch K1 and the circuit breaker QF1; the switches S1, S2, S3, K, K1 and the circuit breakers QF, QF1 The position signal and the converter valve side current signal Iva, Ivb, Ivc and the grid side current Ia, Ib, Ic and the DC side current signal Idp, Idn and the DC side voltage signal Udp, Udn and the monitoring signal of the converter R Enter the control and protection system CP; the control and protection system CP issues the opening and closing commands of the knife switch and the circuit breaker, and sends out the control and trigger commands of the converter R. Among them, the design method of the DC ice-melting device with special converter transformer with static var compensation function includes the following steps:

1) Determine the range of lines covered by the DC deicing device

Determine the line that needs to use the device for ice melting according to the location where the DC ice melting device is used, including individual lines that may be connected in series through substations for ice melting in special cases. According to the type of wires of each line, the DC resistance value of each wire of the line at 20°C can be obtained.

2) Pre-select the ice-melting current of each wire

Calculate the minimum ice-melting current of each line under typical ice-covered conditions (for example: -5°C, wind speed 5m/s, ice thickness 10mm, and complete ice melting within 1 hour) according to the Burgersdorff formula, and take the calculated value 1.1 times is the pre-selected ice-melting current for each wire, that is

I _dpr = 1.1 _Ide·min (1)

In the formula, I _dpr - the pre-selected ice-melting current of each wire, kA; I _{de · min} - the minimum ice-melting current of the line, kA.

3) Determine the maximum allowable current of each wire

Calculate the maximum allowable current I _max of each conductor according to the calculation method provided in Article 5.0.6 of the "Code for Design of 110kV-750kV Overhead Transmission Lines" in GB5045-2010. Calculation conditions: ambient temperature 10°C, wind speed 0.5 m/s, allowable temperature of the conductor 90°C, radiation coefficient 0.9, absorption coefficient 0.9, sunlight intensity 0.1W/cm ² .

4) Calculate the DC voltage drop and DC power of each line when the ice-melting current is preselected;

According to the method of connecting two-phase wires in series, that is, "one to one return" method, or "1-1" method, calculate the DC voltage drop and DC power of each line at the time of pre-selecting the ice-melting current, which is the following formula

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}}\mathrm{<span\; class="notranslate">\; RL</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dc</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="I\; dN"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">I</figure-callout></span><figure-callout\; id="2"\; label="I\; dN"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}^{\mathrm{<span\; class="notranslate">dN</span>}}\mathrm{<span\; class="notranslate">\; RL</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _dpr - the DC voltage drop of each wire when the ice is melted in the "one-to-one-return" method, kV; R-the DC resistance of the ice-melting line at 20°C, Ω/km; L-the length of the line, km; P _de -the wires The DC power when the ice is melted in the "one-to-one-back" method, MW.

5) Determine the rated current parameters of the DC ice melting device

Determine the rated DC power, DC current and DC voltage of the DC ice-melting device based on the maximum value calculated by formulas (1) and (2), and the rated DC power, rated DC current and rated DC voltage of the DC ice-melting device are greater than or equal to The maximum value calculated by formulas (1) and (2), and the rated DC current is less than the maximum value of the maximum allowable current I _max of the wire, that is

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span>\\ \mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span>\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dpr</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \}</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _dN - rated DC voltage of DC ice melting device, kV; I _dN - rated DC current of DC ice melting device, kA; P _dN - rated DC power of DC ice melting device, MW; i - use the DC ice melting device Line number for ice melting.

6) Calculate the ideal no-load DC voltage of the converter at the rated firing angle

The ideal no-load DC voltage of the converter at the rated firing angle is calculated by the following formula, namely

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dio\; N</span>}}<span\; class="notranslate">\; =</span>\frac{\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}{\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; xn</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; rn</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

U_K％为系统阻抗电压U_S％、换流变阻抗电压U_T％与换相电抗器阻抗电压U_CR％之和，设计中可忽略系统阻抗电压；d_rn-直流阻性压降标幺值，取0；V_T-换流器正向导通压降，取0。In the formula, U _dioN - the ideal no-load DC voltage at the rated firing angle, kV; α _N - the rated firing angle, the firing angle corresponding to the rated DC voltage and DC power conditions, taking 5-20°; d _xn - DC per unit value of inductive voltage drop,

U _K ％ is the sum of system impedance voltage U _S ％, commutation transformer impedance voltage U _T ％ and commutation reactor impedance voltage U _CR ％, the system impedance voltage can be ignored in the design; d _rn - DC resistive voltage drop per unit Value, take 0; V _T -converter forward conduction voltage drop, take 0.

7) Calculate the rated AC voltage on the valve side of the commutation reactor

The rated AC voltage on the valve side of the commutation reactor is calculated according to the following formula, namely

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; di</span>}\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; N</span>}}}{\mathrm{<span\; class="notranslate">\; 1.35</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _VN is the AC voltage on the valve side of the commutation reactor, kV.

8) Calculate the rated AC voltage on the commutation reactor side of the special converter transformer

The rated AC voltage on the commutation reactor side of the special converter transformer is calculated according to the following formula, namely

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; \%</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

In the formula, U _2N is the AC voltage on the commutation reactor side of the special converter transformer, kV; U _CR % is the impedance voltage of the commutation reactor, which is 0-0.06, and when it is 0, the commutation reactor is not used.

9) Calculate the rated current of the AC side of the converter

The rated current on the AC side of the converter is calculated using the following formula, namely

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.816</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; dN</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

In the formula, I _VN - the rated valve side current of the converter, kA.

10) Calculate the inductance value of the commutation reactor

The inductance value of the commutation reactor is calculated by the following formula

${\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="u\; CR\; \%"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">u</figure-callout></span><figure-callout\; id="2"\; label="u\; CR\; \%"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; CR</span>}}<span\; class="notranslate">\; \%</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;f</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

In the formula, L _CR - commutation reactor inductance value, H; U _CR % - commutation reactor impedance voltage.

11) Calculate the rated capacity of the dedicated converter transformer

The dedicated converter transformer adopts a three-phase transformer, and the rated capacity is calculated by the following formula, namely

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; VN</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

In the formula, S _N - rated capacity of special converter transformer, MVA; K - harmonic power multiple, take 0.08-0.12.

12) Calculate the inductive reactance of the dedicated converter transformer

The inductive reactance of the dedicated converter transformer is calculated using the following formula

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

In the formula, X _T - special converter transformer impedance, Ω; U _T % - special converter transformer impedance voltage, take 0.08-0.12, take a larger value when there is no commutation reactor, and take a smaller value when there is a commutation reactor.

13) Determine the thyristor controlled reactor TCR or thyristor switching reactor TSR branch capacity and rated current

When the DC deicing device is converted into a thyristor-controlled reactor TCR or a thyristor-switched reactor TSR, the branch capacity of the thyristor-controlled reactor TCR or thyristor-switched reactor TSR is determined by the capacity of the dedicated converter transformer, so

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; SVCN</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}\\ {\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; SVCN</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; SVCN</span>}}}{\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; an</span>}}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

In the formula, Q _SVCN - rated capacity of thyristor controlled reactor TCR or thyristor switched reactor TSR, MVAr; I _SVCN - rated current of thyristor controlled reactor TCR or thyristor switched reactor TSR branch, kA.

14) Determine the total inductance value of the thyristor controlled reactor TCR or thyristor switching reactor TSR branch

The total inductance value of thyristor controlled reactor TCR or thyristor switching reactor TSR branch is calculated by the following formula, namely

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; SVC</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="N"\; filenames="HDA0000132714990000011.png,HDA0000132714990000031.png"\; state="\{\{state\}\}">N</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 9</span>}{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; )</span>$

In the formula, X _SVCY - thyristor controlled reactor TCR or thyristor switching reactor TSR branch reactance value, Ω.

15) Determine the thyristor control reactor TCR or thyristor switching reactor TSR branch to increase the inductance value of the reactor in addition to the commutation reactor

For the thyristor controlled reactor TCR or thyristor switched reactor TSR branch, the inductance value of the reactor needs to be increased according to the following formula, namely

In the formula, T _{CR Δ} - the inductance value of the thyristor-controlled reactor TCR branch increased reactor, H; α _N - the delayed trigger angle of the thyristor-controlled reactor TCR rated capacity, °, 95-104°; L _TSR·Δ - thyristor switching reactor TSR branch increases the inductance value of the reactor, H.

16) Determine the loop inductance of the DC ice melting device in zero power mode

For the six-pulse, use a thyristor-controlled reactor TCR or a thyristor-switched reactor TSR branch to add one phase of the reactor as a smoothing reactor, and the inductance of the entire loop in the zero-power mode of the DC deicing device is calculated according to the following formula, namely

In the formula, L _dcs - the loop inductance value of the DC deicing device in zero power mode, H;

17) Determine the minimum allowable current in the zero power mode of the DC ice melting device

For the six-pulse DC deicing device, one phase of the added reactor is used as the smoothing reactor, and the minimum allowable current in zero power mode is calculated according to the following formula, namely

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; al</span>}\mathrm{<span\; class="notranslate">\; min</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; sr</span>}}\frac{{\mathrm{<span\; class="notranslate">\; 0.0931</span>}\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; dio\; N</span>}}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; dcs</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 15</span>}<span\; class="notranslate">\; )</span>$

In the formula, I _almin - the minimum allowable current of the DC ice melting circuit, kA; K _sr - the reliability factor to ensure that the current is not continuous during the zero power test, taking 1.2-2.0.

18) Design AC filter

The AC filter design is completed according to the harmonic and reactive power characteristics of the DC deicing device operating in zero power mode at rated current.

Claims (10)

1. method for designing with special-purpose converter transformer DC de-icing device; The special-purpose converter transformer DC de-icing device of said band has the static reactive function; Include one or two special-purpose converter transformer T, one group or two groups of reactor L1a, L1b, L1c, one group or two group of six pulse conversion device R; One group or two groups of reactor L2a, L2b, L2c; Disconnecting link S1, S2, S3, S4, control protection system CP, alternating current filter group F; Reactor L1a, L1b, L1c are commutating reactance under the DC ice melting pattern; Be the part of thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR under the reactive power compensation pattern, reactor L2a, L2b, L2c parallel three phase or are smoothing reactor under the DC ice melting pattern, are the part of thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR under the reactive power compensation pattern; Under the DC ice melting pattern; Converter R AC side links to each other with special-purpose converter transformer T through reactor L1a, L1b, L1c; Converter R DC side links to each other with disconnecting link S1, S2, S3, S4 through reactor L2a, L2b, L2c, and special-purpose converter transformer T is connected with AC system with circuit breaker Q F through isolation switch K; Under the reactive power compensation pattern; Be under thyristor-controlled reactor TCR or the thuristor throw-in and throw-off reactor TSR pattern; Valve V1 among the converter R, V4 inverse parallel connection afterwards and after reactor L2a, L1c connect are connected on special-purpose converter transformer T low-pressure side b, c is alternate; Valve V5 among the converter R, V2 inverse parallel connection afterwards and after reactor L1a, L2b connect are connected on special-purpose converter transformer T low-pressure side a, c is alternate; Valve V3 among the converter R, V6 inverse parallel connection afterwards and after reactor L2c, L1b connect are connected on special-purpose converter transformer T low-pressure side a, b is alternate, and special-purpose converter transformer T is connected with AC system with circuit breaker Q F through isolation switch K; Filter F is connected on converter transformer T mains side through isolation switch K1 and circuit breaker Q F1; The position signalling of disconnecting link S1, S2, S3, K, K1 and circuit breaker Q F, QF1 and the change of current become the monitor signal access control protection system CP of current on valve side signal Iva, Ivb, Ivc and current on line side Ia, Ib, Ic and DC side current signal Idp, Idn, Idgnd and dc voltage signal Udp, Udn and converter R; Control protection system CP sends the control and the trigger command of deciliter ordering and send converter R of disconnecting link and circuit breaker;

The DC ice melting that it is characterized in that having the special-purpose converter transformer of band of the static reactive function Design of device method of holding concurrently comprises the steps:

1) confirms that DC de-icing device covers line range;

2) each lead ice melting current of preliminary election;

3) confirm each lead maximum permissible current;

4) calculate direct current pressure drop and the direct current power of each circuit when the preliminary election ice melting current;

5) confirm the DC de-icing device nominal parameter;

6) calculate converter ideal no-load direct voltage under specified trigger angle;

7) calculate the specified alternating voltage of commutating reactor valve side;

8) calculate the specified alternating voltage of special-purpose converter transformer commutating reactor side;

9) calculate converter AC side rated current;

10) calculate the commutating reactor inductance value;

11) calculate special-purpose converter transformer rated capacity;

12) calculate special-purpose converter transformer induction reactance;

13) confirm thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR branch road rated current and rated capacity;

14) confirm thyristor-controlled reactor TCR or the total induction reactance value of thuristor throw-in and throw-off reactor TSR branch road;

15) confirm that thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR branch road increase the inductance value of reactor except that commutating reactor;

16) confirm loop inductance under the DC de-icing device zero energy pattern;

17) confirm minimum acceptable current under the DC de-icing device zero energy pattern;

18) design alternating current filter.

2. the method for designing of the special-purpose converter transformer DC de-icing device of band according to claim 1 is characterized in that above-mentioned steps 1) confirm that the method for DC de-icing device covering line range is following:

Confirm the circuit that needs utilize this device to carry out ice-melt according to the DC de-icing device place to use, comprising in particular cases possibly be connected in series through transformer station carries out the individual line of ice-melt; Can obtain the dc resistance of each lead of circuit 20 ℃ the time according to each line conductor model;

Above-mentioned steps 2) method of each lead ice melting current of preliminary election is following:

Calculate the minimum ice melting current of each circuit under typical icing condition according to boolean Gus Dao Erfu formula, 1.1 times that get calculated value are each lead preliminary election ice melting current, promptly

I _dpr＝1.1I _de·min (1)

In the formula, I _Dpr-each lead preliminary election ice melting current, kA; I _DeminThe minimum ice melting current of-circuit, kA.

3. the method for designing of the special-purpose converter transformer DC de-icing device of band according to claim 1 is characterized in that above-mentioned steps 4) method of calculating direct current pressure drop and the direct current power of each circuit when the preliminary election ice melting current is following:

According to two phase conductor series systems, i.e. " one goes one time " mode, or " 1-1 " mode of title is calculated direct current pressure drop and the direct current power of each circuit when the preliminary election ice melting current, i.e. following formula

$\left\{\begin{array}{c}{U}_{\mathrm{dpr}}=2I_{\mathrm{dpr}}\mathrm{RL}\\ P_{\mathrm{dc}}=2I_{\mathrm{dN}}^2\mathrm{RL}\end{array}\right.---\left(2\right)$

In the formula, U _DprDirect current pressure drop during-each lead " goes a time " mode ice-melt, kV; 20 ℃ of D.C. resistances of R-DC ice-melting, Ω/km; The L-line length, km; P _DeDirect current power during-each lead " goes a time " mode ice-melt, MW.

4. the method for designing of the special-purpose converter transformer DC de-icing device of band according to claim 1 is characterized in that above-mentioned steps 5) confirm that the method for DC de-icing device rated current parameter is following:

The maximum that calculates with formula (1) and (2) is specified direct current power, direct current and the direct voltage that DC de-icing device is confirmed on the basis; The maximum that specified direct current power, rated direct current and the rated direct voltage of DC de-icing device calculates more than or equal to formula (1) and (2), and rated direct current is less than lead maximum permissible current I _MaxIn maximum, promptly

$\left\{\begin{array}{c}{U}_{\mathrm{dN}}\&GreaterEqual;\max \left\{U_{\mathrm{dpr}\&CenterDot;i}\right\}\\ \max \left\{I_{\mathrm{dpr}\&CenterDot;i}\right\}\&le;I_{\mathrm{dN}}\&le;\max \left\{I_{\max \&CenterDot;i}\right\}\\ P_{\mathrm{dN}}\&GreaterEqual;\max \left\{P_{\mathrm{dpr}\&CenterDot;i}\right\}\end{array}\right.---\left(3\right)$

In the formula, U _DN-DC de-icing device rated direct voltage, kV; I _DN-DC de-icing device rated direct current, kA; P _DNThe specified direct current power of-DC de-icing device, MW; I-utilizes this DC de-icing device to carry out the DC ice-melting sequence number.

5. the method for designing of the special-purpose converter transformer DC de-icing device of band according to claim 1 is characterized in that above-mentioned steps 6) method of calculating converter ideal no-load direct voltage under specified trigger angle is following:

The ideal no-load direct voltage of converter under specified trigger angle adopts computes, promptly

$U_{\mathrm{dioN}}=\frac{\frac{U_{\mathrm{dN}}}{n}+V_T}{\cos {\mathrm{\&alpha;}}_N-d_{\mathrm{xn}}-d_{\mathrm{rn}}}---\left(4\right)$

In the formula, U _DioNIdeal no-load direct voltage under the-specified trigger angle, kV; α _N-specified triggering trigger angle, the trigger angle of correspondence when rated direct voltage and direct current power operating mode, °, get 5 °-20 °; N-six pulse conversion device numbers, six pulse conversion devices get 1, and the 12 pulse conversion devices that the doube bridge series connection forms get 2; d _Xn-direct current perception pressure drop perunit value, U _K% is the system impedance voltage U _S%, change of current impedance voltage U _T% and commutating reactor impedance voltage U _CRThe % sum can be ignored system impedance voltage in the design; d _RnThe resistive pressure drop perunit value of-direct current gets 0; V _T-converter forward conduction voltage drop gets 0.

6. the method for designing of the special-purpose converter transformer DC de-icing device of band according to claim 1 is characterized in that above-mentioned steps 7) method of calculating the specified alternating voltage of commutating reactor valve side is following:

The specified alternating voltage of commutating reactor valve side is calculated as follows, promptly

$U_{\mathrm{VN}}=\frac{U_{\mathrm{di}0N}}{1.35}---\left(5\right)$

In the formula, U _VNBe commutating reactor valve top-cross stream voltage, kV.

7. the method for designing of the special-purpose converter transformer DC de-icing device of band according to claim 1 is characterized in that above-mentioned steps 8) method of calculating the specified alternating voltage of special-purpose converter transformer commutating reactor side is following:

The specified alternating voltage of special-purpose converter transformer commutating reactor side is according to computes, promptly

$U_{2N}=\frac{U_{\mathrm{VN}}}{1-U_{\mathrm{CR}}\%}---\left(6\right)$

In the formula, U _2NBe special-purpose converter transformer commutating reactor top-cross stream voltage, kV; U _CR% is the commutating reactor impedance voltage, gets 0-0.06, is taken as at 0 o'clock and does not promptly use commutating reactor, and converter directly is connected on special-purpose converter transformer outlet side.

8. the method for designing of the special-purpose converter transformer DC de-icing device of band according to claim 1 is characterized in that above-mentioned steps 9) method of calculating converter AC side rated current is following:

Converter AC side rated current electric current adopts computes, promptly

$I_{\mathrm{VN}}=\sqrt{\frac{2}{3}}{I}_{\mathrm{dN}}=0.816I_{\mathrm{dN}}---\left(7\right)$

In the formula, I _VN-converter rated current on valve side, kA.

9. the method for designing of the special-purpose converter transformer DC de-icing device of band according to claim 1 is characterized in that above-mentioned steps 10) method of calculating the commutating reactor inductance value is following:

The commutating reactor inductance value adopts computes

$L_{\mathrm{CR}}=\frac{U_{2N}\&times;U_{\mathrm{CR}}\%}{2\mathrm{\&pi;f}\&times;I_{\mathrm{VN}}}---\left(8\right)$

In the formula, L _CR-commutating reactor inductance value, H; U _CR%-commutating reactor impedance voltage;

Above-mentioned steps 11) method of the special-purpose converter transformer rated capacity of calculating is following:

For six pulse conversion devices, special-purpose converter transformer adopts a three-phase transformer, and for 12 pulse conversion devices, special-purpose converter transformer adopts two three-phase transformers, and the separate unit rated capacity adopts computes, promptly

$S_N=\sqrt{3}{U}_{2N}{I}_{\mathrm{VN}}(1+K)---\left(9\right)$

In the formula, S _N-special-purpose converter transformer rated capacity, MVA; K-harmonic power multiple is got 0.08-0.12;

Above-mentioned steps 12) method of the special-purpose converter transformer induction reactance of calculating is following:

Special-purpose converter transformer induction reactance adopts computes

$X_T=\frac{U_{2N}^2}{S_N}\&times;U_T\%---\left(10\right)$

In the formula, X _T-special-purpose converter transformer impedance, Ω; U _TThe special-purpose converter transformer impedance voltage of %-is got 0.08-0.12, gets big value during no commutating reactor, gets the small value when commutating reactor is arranged;

Above-mentioned steps 13) confirm that the method for thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR branch road capacity and rated current is following:

When DC de-icing device converted thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR operation into, thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR branch road capacity were decided by special-purpose converter transformer capacity, so

$\left\{\begin{array}{c}{Q}_{\mathrm{SVCN}}=S_N\\ I_{\mathrm{SVCN}}=\frac{Q_{\mathrm{SVCN}}}{\sqrt{3}{U}_{\mathrm{an}}}\end{array}\right.---\left(11\right)$

In the formula, Q _SVCN-thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR rated capacity, MVAr; I _SVCN-thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR branch road rated current, kA;

Above-mentioned steps 14) confirm that the method for thyristor-controlled reactor TCR or the total induction reactance value of thuristor throw-in and throw-off reactor TSR branch road is following:

The total induction reactance value of thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR branch road adopts computes, promptly

$X_{\mathrm{SVC}\&CenterDot;Y}=\frac{U_{2N}^2}{9Q_N}---\left(12\right)$

In the formula, X _SVCY-thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR branch road reactance value, Ω;

Above-mentioned steps 15) it is following to confirm that thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR branch road increase the method for inductance value of reactor except that commutating reactor:

For thyristor-controlled reactor TCR or thuristor throw-in and throw-off reactor TSR branch road, the inductance value that needs to increase reactor is calculated as follows, promptly

In the formula, L _{The TCR Δ}-thyristor-controlled reactor TCR branch road increases the inductance value of reactor, H; α _NDelay trigger angle during-thyristor-controlled reactor TCR nominal capacity, °, get 95-104 °; L _{The TSR Δ}-thuristor throw-in and throw-off reactor TSR branch road increases the inductance value of reactor, H.

10. the method for designing of the special-purpose converter transformer DC de-icing device of band according to claim 1 is characterized in that above-mentioned steps 16) confirm that the method for loop inductance under the DC de-icing device zero energy pattern is following:

For 12 pulsation, adopt the parallel three phase that increases in thyristor-controlled reactor TCR or the thuristor throw-in and throw-off reactor TSR branch road in the reactor as smoothing reactor, whole loop inductance is according to computes, promptly under the DC de-icing device zero energy pattern

For six pulsation, adopting increases by one in the reactor as smoothing reactor in thyristor-controlled reactor TCR or the thuristor throw-in and throw-off reactor TSR branch road, and whole loop inductance is according to computes, promptly under the DC de-icing device zero energy pattern

$\left\{\begin{array}{c}{L}_{\mathrm{dcs}}=1.5(\frac{X_T}{2\mathrm{\&pi;f}}+L_{\mathrm{CR}})+L_{\mathrm{TCR}\&CenterDot;\mathrm{\&Delta;}}\\ L_{\mathrm{dcs}}=1.5(\frac{X_T}{2\mathrm{\&pi;f}}+L_{\mathrm{CR}})+L_{\mathrm{TSR}\&CenterDot;\mathrm{\&Delta;}}\end{array}\right.---\left(15\right)$

In the formula, L _DcsLoop inductance value under the-DC de-icing device zero energy pattern, H;

Above-mentioned steps 17) confirm that the method for minimum acceptable current under the DC de-icing device zero energy pattern is following:

For 12 pulsating direct current deicing devices, minimum acceptable current is according to computes, promptly under the zero energy pattern

$I_{\mathrm{al}\min }=K_{\mathrm{sr}}\frac{0.023\&times;2\&times;U_{\mathrm{dioN}}}{\mathrm{\&omega;}{L}_{\mathrm{dcs}}}---\left(16\right)$

For six pulsating direct current deicing devices, minimum acceptable current is according to computes, promptly under the zero energy pattern

$I_{\mathrm{al}\min }=K_{\mathrm{sr}}\frac{0.0931U_{\mathrm{dioN}}}{\mathrm{\&omega;}{L}_{\mathrm{dcs}}}---\left(17\right)$

In the formula, I _Almin-DC ice melting loop minimum acceptable current, kA; K _Sr-not interrupted the safety factor of electric current when guaranteeing the zero energy test is got 1.2-2.0;

Above-mentioned steps 18) method of design alternating current filter is following:

Harmonic wave when running on the zero energy pattern according to DC de-icing device with rated current and idle characteristic are accomplished the alternating current filter design.

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