CN103107550B - Method for choosing current converting variational joint control mode based on converter loss - Google Patents

Abstract

A method for choosing a current converting variational joint control mode based on converter loss comprises the following steps: calculating converter losses under typical working conditions according to international electrotechnical commission (IEC) standard definition; and then combining a trigger angle, a converter transformer valve side winding wire voltage effective value, direct current voltage and direct current on two ends of a converter transformer valve, fitting a direct mathematic relationship of the converter losses and operation condition parameters under a current converting variational joint constant angle control mode and a constant voltage control mode; real-time calculating the converter losses under the current converting variational joint constant angle control mode and the constant voltage control mode according to actual direct current transmission system operation conditions, and choosing the current converting variational joint control mode which is small in loss by comparing the converter losses under the current converting variational joint constant angle control mode and the constant voltage control mode according to actual direct current transmission system operation conditions. Therefore, an operation mode of a direct current system can be arranged in an optimized manner, and high losses caused by a certain operation mode can be reduced.

Description

A kind of method selecting change of current variation joint control model based on converter loss

Technical field

The invention belongs to high-voltage dc transmission electrical domain, particularly a kind of method selecting change of current variation joint control model based on converter loss.

Background technology

In HVDC (High Voltage Direct Current) transmission system, the control of change of current variation joint plays an important role for the operation of HVDC (High Voltage Direct Current) transmission system, according to the difference of controlled variable, change of current variation joint control model is divided into invariable-angle control and determines voltage control, the former refers to keep Trigger Angle α or extinguish angle γ to be the reference value of requirement, and the latter refers to keep U _di0(unloaded direct voltage) reference value for requiring.

Determine Angle ambiguity pattern, the converter Trigger Angle of actual measurement and the reference value of setting compare by change of current variation joint controller, obtain differential seat angle.Prescribe a time limit when differential seat angle exceedes on operating dead zone, send the order of falling tap; Under differential seat angle exceedes operating dead zone in limited time, the order rising tap is sent.There is certain time delay when performing change of current variation joint lifting instruction, be elevated when the disturbance of AC and DC voltage to avoid tap.

Determine voltage mode control, change of current variation joint controller becomes tap position according to the change of current of reality and the change of current becomes AC voltage calculating converter transformer valve side floating voltage.The reference value of the converter transformer valve side floating voltage calculated and setting is compared, obtains voltage error.The change of current becomes tapped control and produces according to the voltage error obtained the order that the lifting/lowering change of current becomes tap.Prescribe a time limit when voltage error exceedes on operating dead zone, send the order of falling tap; Under voltage error exceedes operating dead zone in limited time, the order rising tap is sent.There is certain time delay when performing tap lifting instruction, be elevated when the disturbance of AC and DC voltage to avoid tap.

The different control models of change of current variation joint can affect converter loss, and the waveform be in operation due to converter is complicated, goes back the method for the good direct measuring loss of neither one at present.The method of usual employing is each loss component calculating thyristor valve respectively, is finally added the loss obtaining converter.Do not have at present and carry out computational analysis for converter loss specially, thus the operation and maintenance of DC transmission system is optimized.

Summary of the invention

The object of the invention is: be to propose a kind of method selecting change of current variation joint control model based on converter loss, according to DC transmission system operating condition, the loss of converter can be calculated in real time, select the change of current variation joint control model that loss is little.

In order to reach above-mentioned purpose, solution of the present invention is:

Select a method for change of current variation joint control model based on converter loss, comprise the following steps:

(1) according to the loss of converter under IEC61803 standard definition calculating typical condition;

(2) according to the loss that step (1) calculates, in conjunction with trigger angle, valve winding in converter transformer line voltage effective value, valve two ends direct voltage and direct current, simulate change of current variation joint invariable-angle control pattern and the direct relationship under determining voltage control control model between converter loss and operating condition parameter;

P _α＝f _α(α，U _l,U _dc,I _dc) （1）

P _U＝f _U(α，U _l,U _dc,I _dc) （2）

P _αand P _ube respectively change of current variation joint and determine Angle ambiguity pattern and the loss determined under voltage control control model, unit kW; α is trigger angle, unit degree; U _lfor valve winding in converter transformer line voltage effective value, unit kV; U _dcfor valve two ends direct voltage, unit kV; I _dcfor direct current, unit A.

(3) according to the DC transmission system operating condition of reality, according to the direct relationship that step (2) obtains, real-time calculating change of current variation joint is determined Angle ambiguity control model and is determined the loss of converter under voltage control control model, compared by both, select the change of current variation joint control model that loss is little.

Above-mentioned typical condition specifically refers to, direct current is respectively specified I _dcand 0.8I _dc, 0.6I _dc, 0.4I _dc, 0.2I _dcvarious operating conditions.

After above-mentioned formula (1) matching, form is as follows:

$P_{\mathrm{\α}}=U_l^2[k_1\mathrm{\α}+{\mathrm{\α}}^2(k_2{U}_{\mathrm{dc}}^2-k_3-k_4\frac{U_{\mathrm{dc}}}{\mathrm{\α}})+{\mathrm{\α}}^4(k_5+k_6{U}_{\mathrm{dc}}^4)]+U_{\mathrm{dc}}(k_7-k_8{U}_{\mathrm{dc}}-\frac{k_9}{U_{\mathrm{dc}}})$

$+I_{\mathrm{dc}}(k_{10}+k_{11}{U}_l{I}_{\mathrm{dc}}+k_{12}{U}_l^2{I}_{\mathrm{dc}})$

Wherein, k ₁k ₂k ₁₂for fitting coefficient.

After above-mentioned formula (2) matching, form is as follows:

$P_U=U_{\mathrm{dc}}^2[K_1\frac{U_{\mathrm{dc}}}{\mathrm{\α}}-K_2+K_3\frac{U_l^2}{U_{\mathrm{dc}}}\mathrm{\α}+{\mathrm{\α}}^2(K_4{U}_l^2{U}_{\mathrm{dc}}^2{\mathrm{\α}}^2-K_5{U}_l^2)]$

$+U_l^2(K_6{\mathrm{\α}}^2-K_7\mathrm{\α}-K_8{\mathrm{\α}}^4)+I_{\mathrm{dc}}^2(\frac{K_9}{I_{\mathrm{dc}}}+K_{10}{U}_{l}I+K_{11}{U}_l^2)-K_{12}$

Wherein, K ₁k ₂k ₁₂for fitting coefficient.

Beneficial effect of the present invention is, adopt such scheme, the direct mathematical relationship between converter loss and operating condition parameter is given by calculating and matching, can according to the loss of DC transmission system real time execution condition calculating converter, thus the change of current variation joint control model selecting loss less, can the operational mode of Optimum direct current system, reduce the high loss that certain operational mode is brought, have higher using value.

Embodiment

Below in conjunction with specific embodiment, technical scheme of the present invention is described in detail.

The invention provides a kind of method selecting change of current variation joint control model based on converter loss, comprise the steps:

(1) according to the loss of converter under IEC61803 standard definition calculating typical condition; The desirable direct current of typical condition is respectively specified I _dcand 0.8I _dc, 0.6I _dc, 0.4I _dc, 0.2I _dcvarious operating conditions.

(2) according to the loss that step (1) calculates, in conjunction with trigger angle, valve winding in converter transformer line voltage effective value, valve two ends direct voltage and direct current, simulate change of current variation joint invariable-angle control pattern and the direct relationship under determining voltage control control model between converter loss and operating condition parameter; After matching, form is as follows:

$P_{\mathrm{\α}}=U_l^2[k_1\mathrm{\α}+{\mathrm{\α}}^2(k_2{U}_{\mathrm{dc}}^2-k_3-k_4\frac{U_{\mathrm{dc}}}{\mathrm{\α}})+{\mathrm{\α}}^4(k_5+k_6{U}_{\mathrm{dc}}^4)]+U_{\mathrm{dc}}(k_7-k_8{U}_{\mathrm{dc}}-\frac{k_9}{U_{\mathrm{dc}}})$

$+I_{\mathrm{dc}}(k_{10}+k_{11}{U}_l{I}_{\mathrm{dc}}+k_{12}{U}_l^2{I}_{\mathrm{dc}})$

$P_U=U_{\mathrm{dc}}^2[K_1\frac{U_{\mathrm{dc}}}{\mathrm{\α}}-K_2+K_3\frac{U_l^2}{U_{\mathrm{dc}}}\mathrm{\α}+{\mathrm{\α}}^2(K_4{U}_l^2{U}_{\mathrm{dc}}^2{\mathrm{\α}}^2-K_5{U}_l^2)]$

$+U_l^2(K_6{\mathrm{\α}}^2-K_7\mathrm{\α}-K_8{\mathrm{\α}}^4)+I_{\mathrm{dc}}^2(\frac{K_9}{I_{\mathrm{dc}}}+K_{10}{U}_{l}I+K_{11}{U}_l^2)-K_{12}$

Wherein, k ₁k ₂k ₁₂for fitting coefficient, K ₁k ₂k ₁₂for fitting coefficient.

P _αand P _ube respectively change of current variation joint and determine Angle ambiguity pattern and the loss determined under voltage control control model, unit kW; α is trigger angle, unit degree; U _lfor valve winding in converter transformer line voltage effective value, unit kV; U _dcfor valve two ends DC voltage value, unit kV; I _dcfor valve two ends DC current values, unit A.

(3) according to the DC transmission system operating condition of reality, according to the direct relationship that step (2) obtains, real-time calculating change of current variation joint is determined Angle ambiguity control model and is determined the loss of converter under voltage control control model, compared by both, select the change of current variation joint control model that loss is little.

For actual DC power transmission engineering, the loss of typical condition converter as shown in Table 1 and Table 2:

Table 1 determines typical condition attrition table under Angle ambiguity pattern for change of current variation joint

Table 2 determines typical condition attrition table under voltage mode control for change of current variation joint

After change of current variation joint invariable-angle control pattern and the direct relationship matching under determining voltage control control model between converter loss and operating condition parameter, form is as follows:

$P_{\mathrm{\α}}=U_L^2\{\frac{61}{7399}\mathrm{\α}+{\mathrm{\α}}^2(\frac{1009}{2524}\·{10}^{-9}{U}_{\mathrm{dc}}^2-\frac{9}{89077}-\frac{133}{856}\·{10}^{-4}\frac{U_{\mathrm{dc}}}{\mathrm{\α}})+{\mathrm{\α}}^4(\frac{1727}{1913}\·{10}^{-8}+\frac{575}{678}\·{10}^{-18}{U}_{\mathrm{dc}}^4)\}$

$+U_{\mathrm{dc}}(\frac{2007}{106}-\frac{312}{21275}{U}_{\mathrm{dc}}-\frac{87706}{19\·U_{\mathrm{dc}}})+I_{\mathrm{dc}}(\frac{563}{560}+\frac{825}{256}\·{10}^{-8}{U}_L{I}_{\mathrm{dc}}+\frac{1291}{1217}\·{10}^{-9}{U}_L^2{I}_{\mathrm{dc}});$

$P_U=U_{\mathrm{dc}}^2\{\frac{2362}{177\·U_{\mathrm{dc}}}-\frac{95}{4272}+\frac{1894}{995}\·{10}^{-5}\frac{U_L^2}{U_{\mathrm{dc}}}\mathrm{\α}+{\mathrm{\α}}^2(\frac{982}{837}\·{10}^{-19}{U}_L^2{U}_{\mathrm{dc}}^2{\mathrm{\α}}^2-\frac{1265}{249}\·{10}^{-10}{U}_L^2)\}$

$+U_L^2(\frac{5}{36946}{\mathrm{\α}}^2-\frac{241}{28942}\mathrm{\α}-\frac{1751}{276}{\mathrm{\α}}^4)+I_{\mathrm{dc}}^2(\frac{993}{1135\·I_{\mathrm{dc}}}+\frac{2693}{1378}\·{10}^{-8}{U}_L+\frac{908}{493}\·{10}^{-9}{U}_L^2)$

$-\frac{10482}{41}$

The less a kind of change of current variation joint control model of loss in both selections

Finally should be noted that: only illustrate that technical scheme of the present invention is not intended to limit in conjunction with above-described embodiment.Those of ordinary skill in the field are to be understood that: those skilled in the art can modify to the specific embodiment of the present invention or equivalent replacement, but these amendments or change are all being applied within the patent requirements protection range awaited the reply.

Claims (2)

1. select a method for change of current variation joint control model based on converter loss, it is characterized in that comprising the steps:

(1) according to the loss value of converter under IEC61803 standard definition calculating typical condition;

(2) according to the loss value that step (1) calculates, in conjunction with trigger angle, valve winding in converter transformer line voltage effective value, valve two ends DC voltage value and DC current values, simulate change of current variation joint and determine Angle ambiguity pattern and the direct relationship under determining voltage mode control between converter loss and operating condition parameter; Direct relationship form between described converter loss and operating condition parameter is as follows:

P _α=f _α(α, U _l, U _dc, I _dc) formula (1)

P _u=f _u(α, U _l, U _dc, I _dc) formula (2)

P _αand P _ube respectively change of current variation joint and determine Angle ambiguity pattern and the loss determined under voltage mode control, unit kW;

α is trigger angle, unit degree;

U _lfor valve winding in converter transformer line voltage effective value, unit kV;

U _dcfor valve two ends direct voltage, unit kV;

I _dcfor direct current, unit A;

Described formula (1) is as follows:

$\begin{array}{c}{P}_{\mathrm{\α}}=U_1^2[k_1\mathrm{\α}+{\mathrm{\α}}^2(k_2{U}_{\mathrm{dc}}^2-k_3-k_4\frac{U_{\mathrm{dc}}}{\mathrm{\α}})+{\mathrm{\α}}^4(k_5+k_6{U}_{\mathrm{dc}}^4)]+U_{\mathrm{dc}}(k_7-k_8{U}_{\mathrm{dc}}-\frac{k_9}{U_{\mathrm{dc}}})\\ +I_{\mathrm{dc}}(k_{10}+k_{11}{U}_l{I}_{\mathrm{dc}}+k_{12}{U}_l^2{I}_{\mathrm{dc}})\end{array}$

Wherein, k ₁k ₂k ₁₂for fitting coefficient;

Described formula (2) is as follows:

$\begin{array}{c}{P}_U=U_{\mathrm{dc}}^2[K_1\frac{U_{\mathrm{dc}}}{\mathrm{\α}}-K_2+K_3\frac{U_l^2}{U_{\mathrm{dc}}}\mathrm{\α}+{\mathrm{\α}}^2(K_4{U}_l^2{U}_{\mathrm{dc}}^2{\mathrm{\α}}^2-K_5{U}_l^2)]\\ +U_l^2(K_6{\mathrm{\α}}^2-K_7\mathrm{\α}-K_8{\mathrm{\α}}^4)+I_{\mathrm{dc}}^2(\frac{K_9}{I_{\mathrm{dc}}}+K_{10}{U}_l+K_{11}{U}_l^2)-K_{12}\end{array}$

Wherein, K ₁k ₂k ₁₂for fitting coefficient;

(3) according to the DC transmission system operating condition of reality, according to the direct relationship that step (2) obtains, real-time calculating change of current variation joint is determined Angle ambiguity pattern and is determined the loss of converter under voltage mode control, compared by both, select the change of current variation joint control model that loss is little.

2. a kind of method selecting change of current variation joint control model based on converter loss as claimed in claim 1, it is characterized in that, described typical condition comprises: direct current is respectively specified I _dc, 0.8I _dc, 0.6I _dc, 0.4I _dcand 0.2I _dcunder various operating conditions.