CN104376209A - Theoretical line loss computation method for high-voltage transmission long line provided with shunt reactors - Google Patents

Abstract

The invention provides a theoretical line loss computation method for a high-voltage transmission long line provided with shunt reactors. The method comprises the steps that a theoretical line loss computation equivalent double-II model of the high-voltage transmission long line to be measured is established; a theoretical line loss computation time period of the line to be measured is divided into a plurality of load actual measurement sections; measurement data of each of the load actual measurement sections at the two ends of the line to be measured are obtained from EMS; a phase current effective value of each load actual measurement section which a parallel branch reactive current is compensated for is computed; the active power loss of a resistor, at each load actual measurement section, of the line to be measured is computed; the active power loss of the shunt reactor, at each load actual measurement section, of the line to be measured is computed; the total active power loss of the line to be measured at all the load actual measurement sections is computed; integral computation is conducted to obtain the theoretical line loss of the line to be measured within the whole computation time period. By the adoption of the method, the accuracy of theoretical line loss computation of the high-voltage long line provided with the shunt reactors is greatly improved, and a reliable basis is provided for further economic operation analysis of high-voltage grids.

Description

A kind of high voltage power transmission long-line theory line loss calculation method with shunt reactor

Technical field

The present invention relates to technical field of power systems, specifically a kind of high voltage power transmission long-line theory line loss calculation method with shunt reactor.

Background technology

Line loss theoretical calculation is the important technical of analysis and research high-voltage fence economical operation characteristic, remote high pressure (comprising UHV (ultra-high voltage), extra-high voltage) transmission line of electricity is as region mains network important component part, often carry electrical network contact, carry the important task of a large amount of electric power, corresponding line loss theoretical calculation result is significant to the performance driving economy analyzing whole electrical network.

Traditional transmission line of electricity theoretical line loss caluclation method, all based on circuit R-L model, namely the impact of line distribution capacitance electric current is ignored, only utilize EMS (Energy Management System) to survey the active loss of circuit head end power current and known line resistance parameter integral computing electric power line, this algorithm is for mesolow and the shorter circuit of distance has higher computational accuracy.

But, actual high-voltage and even UHV (ultra-high voltage), extra-high voltage long-distance transmission line, not only capacitance current is very large, and in order to limit power-frequency overvoltage, often in circuit two ends installing parallel high voltage reactor.Traditional theoretical line loss caluclation method ignoring line distribution capacitance electric current and the impact of parallel high voltage reactor will cause result of calculation distortion, and further impact to voltage economy operation of power grid analysis result.

Summary of the invention

The object of the invention is to overcome the drawback that traditional transmission line of electricity theoretical line loss caluclation method ignores line distribution capacitance electric current and the impact of parallel high voltage reactor, a kind of high voltage power transmission long-line theory line loss calculation method with shunt reactor is provided, long for high voltage power transmission line parallel branch road reactive current impact is taken into account, only utilize the conventional EMS metric data in transmission line of electricity two ends, extract phasor without the need to high-speed sampling and filtering, accurately can calculate the theoretical loss of the long line of high voltage power transmission of band shunt reactor.

Technical scheme of the present invention is:

With a high voltage power transmission long-line theory line loss calculation method for shunt reactor, comprise the following steps:

(1) according to circuit power frequency impedance to be measured, distributed capacitance parameter and circuit two ends to be measured shunt reactor parameter, the two Π model of line theory line loss calculation to be measured equivalence is set up;

(2) be several load measurement sections by line theory line loss calculation Time segments division to be measured;

(3) from EMS, obtain the metric data of circuit two ends to be measured at each load measurement section, comprise active power, reactive power, line voltage effective value and phase current effective value;

(4) according to the two Π models of line theory line loss calculation to be measured equivalence and circuit two ends to be measured at the metric data of each load measurement section, calculate the phase current effective value of circuit two ends to be measured after each load measurement section compensates this side parallel branch reactive current:

(5) the phase current effective value after each load measurement section compensates this side parallel branch reactive current according to circuit power frequency resistance parameter to be measured and circuit two ends to be measured, calculates the resistance active power loss of circuit to be measured at each load measurement section;

(6) according to the nominal loss of circuit two ends to be measured shunt reactor and rated voltage parameter and circuit two ends to be measured at the line voltage effective value of each load measurement section, calculate the shunt reactor active power loss of circuit to be measured at each load measurement section;

(7) circuit to be measured is added up at the resistance active power loss of each load measurement section and shunt reactor active power loss, obtain the total active power loss of circuit to be measured at each load measurement section;

(8) circuit to be measured is carried out integral and calculating at total active power loss of each load measurement section, obtain the theory wire loss of circuit to be measured at whole calculation interval.

The high voltage power transmission long-line theory line loss calculation method of described band shunt reactor, in step (4), the phase current effective value of described circuit two ends to be measured after each load measurement section compensates this side parallel branch reactive current, is obtained by following formulae discovery:

$I_{\mathrm{act}}^{\′}=\frac{U_{\mathrm{at}}}{\sqrt{3}}(\frac{\mathrm{C\ω}}{4}-\frac{1}{X_a})$

$I_{\mathrm{bct}}^{\′}=\frac{U_{\mathrm{bt}}}{\sqrt{3}}(\frac{\mathrm{C\ω}}{4}-\frac{1}{X_b})$

Wherein, I ' _at, I ' _btrepresent the phase current effective value of circuit two ends to be measured after load measurement section t compensates this side parallel branch reactive current respectively, I ' _act, I ' _bctrepresent the equivalent parallel branch road reactive current of circuit two ends to be measured at load measurement section t respectively, I _at, I _btrepresent the phase current effective value of circuit two ends to be measured at load measurement section t respectively, represent the transmission power factor angle of circuit two ends to be measured at load measurement section t respectively, U _at, U _btrepresent the line voltage effective value of circuit two ends to be measured at load measurement section t respectively, C represents line distribution capacitance parameter to be measured, and ω represents angular frequency, X _a, X _brepresent circuit two ends to be measured shunt reactor equivalent reactance respectively, Q _at, Q _btrepresent the reactive power of circuit two ends to be measured at load measurement section t respectively, P _at, P _btrepresent the active power of circuit two ends to be measured at load measurement section t respectively;

In step (5), described circuit to be measured, at the resistance active power loss of each load measurement section, is obtained by following formulae discovery:

$\mathrm{\Δ}{P}_{\mathrm{Rt}}^{\′}=\frac{3R(I_{\mathrm{at}}^{\′2}+I_{\mathrm{bt}}^{\′2})}{2}$

Wherein, Δ P ' _rtrepresent the resistance active power loss of circuit to be measured at load measurement section t, R represents circuit power frequency resistance parameter to be measured;

In step (6), described circuit to be measured, at the shunt reactor active power loss of each load measurement section, is obtained by following formulae discovery:

${\mathrm{\ΔP}}_{\mathrm{Lt}}^{\′}=P_{a0}^{\′}\frac{U_{\mathrm{at}}^2}{U_{\mathrm{aN}}^2}+P_{b0}^{\′}\frac{U_{\mathrm{bt}}^2}{U_{\mathrm{bN}}^2}$

Wherein, Δ P ' _ltrepresent the shunt reactor active power loss of circuit to be measured at load measurement section t, P ' _a0, P ' _b0represent the nominal loss of circuit two ends to be measured shunt reactor respectively, U _aN, U _bNrepresent the rated voltage of circuit two ends to be measured shunt reactor respectively;

In step (7), described circuit to be measured, at total active power loss of each load measurement section, is obtained by following formulae discovery:

ΔP′t＝ΔP′ _Rt+ΔP′ _Lt

Wherein, Δ P ' _trepresent the total active power loss of circuit to be measured at load measurement section t;

In step (8), described circuit to be measured, at the theory wire loss of whole calculation interval, is obtained by following formulae discovery:

ΔW′＝∫ΔP′ _tdt

Wherein, Δ W ' represents the theory wire loss of circuit to be measured at whole calculation interval.

As shown from the above technical solution, the present invention is according to the two Π model of high pressure long line equivalence, take into full account the impact of line distribution capacitance electric current and lines in parallel high voltage reactor, utilize the conventional EMS metric data in circuit both sides, extract phasor without the need to high-speed sampling or filtering and get final product calculation compensation lines in parallel branch current, the active loss of accurate calculating transmission line of electricity to be measured, the little accuracy that but significantly improve band shunt reactor high pressure long-line theory line loss calculation of calculated amount, for further high-voltage fence economic operation analysis provides reliable basis.

Accompanying drawing explanation

Fig. 1 is method flow diagram of the present invention;

Fig. 2 is the two Π model of high voltage power transmission long-line theory line loss calculation of band shunt reactor;

Fig. 3 is the high voltage power transmission long line one-terminal current phasor analysis figure of band shunt reactor.

Embodiment

Below, the present invention is further illustrated with specific embodiment by reference to the accompanying drawings.

As shown in Figure 1, a kind of high voltage power transmission long-line theory line loss calculation method with shunt reactor, comprises the following steps:

S1, utilize power frequency impedance, distributed capacitance parameter and circuit two ends to be measured shunt reactor parameter that circuit to be measured is known, set up the two Π model of equivalence needed for high voltage power transmission long-line theory line loss calculation to be measured;

As shown in Figure 2, Z represents line impedance to be measured, R=r*l, X=x*l, C=c*l, and wherein, l represents line length to be measured, and r represents circuit resistance per unit length to be measured, and x represents circuit unit length to be measured reactance, and c represents circuit capacitance per unit length to be measured, X _a, X _brepresent circuit two ends to be measured shunt reactor equivalent reactance respectively; P _a, Q _a, U _a, I _aand P _b, Q _b, U _b, I _brepresent circuit two ends to be measured and bus A side, the active power of bus B side, reactive power, line voltage effective value, phase current effective value respectively, usually the telemetry (being interposed between a minute level between general data, such as every 5 minutes 1 telemetries) of EMS is derived from.

As shown in Figure 3, look up and down for circuit A to be measured and survey, carry out electric current phasor analysis, can obtain:

$I_{\mathrm{ac}}^{\′}=\frac{U_a}{\sqrt{3}}(\frac{\mathrm{C\ω}}{4}-\frac{1}{X_a})$

Wherein, I ' _arepresent the phase current effective value after this side parallel branch reactive current of circuit A end compensating to be measured, I ' _acrepresent that circuit A to be measured holds equivalent parallel branch road reactive current, represent the transmission power factor angle that circuit A to be measured holds, C represents line distribution capacitance parameter to be measured, and ω represents angular frequency, and value is 314, X _arepresent that circuit A to be measured holds shunt reactor equivalent reactance.

In like manner, look up and down for circuit B to be measured and survey, carry out electric current phasor analysis, can obtain:

$I_{\mathrm{bc}}^{\′}=\frac{U_b}{\sqrt{3}}(\frac{\mathrm{C\ω}}{4}-\frac{1}{X_b})$

Wherein, I ' _brepresent the phase current effective value after this side parallel branch reactive current of circuit B end compensating to be measured, I ' _bcrepresent that circuit B to be measured holds equivalent parallel branch road reactive current, represent the transmission power factor angle that circuit B to be measured holds, C represents line distribution capacitance parameter to be measured, and ω represents angular frequency, and value is 314, X _brepresent that circuit B to be measured holds shunt reactor equivalent reactance.

S2, be that (" section " that relate to herein refers to the concept of time dimension to some sections by high voltage power transmission long-line theory line loss calculation Time segments division to be measured, guarantee that each group metric data corresponds to synchronization), and carry out corresponding load measurement, the measured data of circuit two ends to be measured at each section is obtained from EMS, specifically comprise active power, reactive power, line voltage effective value, phase current effective value, respective electric measures and is designated as P respectively _at, Q _at, U _at, I _atand P _bt, Q _bt, U _bt, I _bt.

S3, the bus A side of certain load measurement section is utilized electrically to measure P _at, Q _at, U _at, I _at, circuit A to be measured can be calculated and hold at the transmission power factor angle of this section

Shunt reactor equivalent reactance X is held again in conjunction with line distribution capacitance parameter C to be measured and circuit A to be measured _a, the equivalent parallel branch road reactive current I ' of circuit A to be measured end at this section can be calculated _act:

$I_{\mathrm{act}}^{\′}=\frac{U_{\mathrm{at}}}{\sqrt{3}}(\frac{\mathrm{C\ω}}{4}-\frac{1}{X_a})$

Based on the two Π model of line equivalent to be measured that step S1 sets up, circuit A to be measured can be calculated and hold the phase current effective value I ' after this section compensates this side parallel branch reactive current _at:

In like manner, the bus B side of this load measurement section is utilized electrically to measure P _bt, Q _bt, U _bt, I _bt, circuit B to be measured can be calculated and hold the phase current effective value I ' after this section compensates this side parallel branch reactive current _bt:

S4, based on line equivalent industrial frequency electric resistance parameter R to be measured, utilize the circuit two ends to be measured that calculated at this load measurement section with the resistance active power loss of circuit to be measured at this section can be obtained:

$\mathrm{\Δ}{P}_{\mathrm{Rt}}^{\′}=\mathrm{\Δ}{P}_{\mathrm{at}}^{\′}+{\mathrm{\ΔP}}_{\mathrm{bt}}^{\′}=\frac{3R(I_{\mathrm{at}}^{\′2}+I_{\mathrm{bt}}^{\′2})}{2}$

S5, based on shunt reactor parameter, the shunt reactor active power loss of circuit to be measured at this section can be calculated:

${\mathrm{\ΔP}}_{\mathrm{Lt}}^{\′}={\mathrm{\ΔP}}_{\mathrm{aLt}}^{\′}+{\mathrm{\ΔP}}_{\mathrm{bLt}}^{\′}=P_{a0}^{\′}\frac{U_{\mathrm{at}}^2}{U_{\mathrm{aN}}^2}+P_{b0}^{\′}\frac{U_{\mathrm{bt}}^2}{U_{\mathrm{bN}}^2}$

Wherein, P ' _a0represent that circuit A to be measured holds the nominal loss of shunt reactor, P ' _b0represent that circuit B to be measured holds the nominal loss of shunt reactor, U _aNrepresent that circuit A to be measured holds the rated voltage of shunt reactor, U _bNrepresent that circuit B to be measured holds the rated voltage of shunt reactor.

S6, according to the total active power loss of circuit to be measured at each load measurement section, integrable calculates the long line of high voltage power transmission of band shunt reactor at the theory wire loss of calculation interval, and concrete formula is:

ΔW′＝∫ΔP′ _tdt＝∫(ΔP′ _at+ΔP′ _bt+ΔP′ _Lt)dt

The above embodiment is only be described the preferred embodiment of the present invention; not scope of the present invention is limited; under not departing from the present invention and designing the prerequisite of spirit; the various distortion that those of ordinary skill in the art make technical scheme of the present invention and improvement, all should fall in protection domain that claims of the present invention determine.

Claims (2)

1. the high voltage power transmission long-line theory line loss calculation method with shunt reactor, is characterized in that, comprise the following steps:

(1) according to circuit power frequency impedance to be measured, distributed capacitance parameter and circuit two ends to be measured shunt reactor parameter, the two Π model of line theory line loss calculation to be measured equivalence is set up;

(2) be several load measurement sections by line theory line loss calculation Time segments division to be measured;

(3) from EMS, obtain the metric data of circuit two ends to be measured at each load measurement section, comprise active power, reactive power, line voltage effective value and phase current effective value;

(4) according to the two Π models of line theory line loss calculation to be measured equivalence and circuit two ends to be measured at the metric data of each load measurement section, calculate the phase current effective value of circuit two ends to be measured after each load measurement section compensates this side parallel branch reactive current:

(5) the phase current effective value after each load measurement section compensates this side parallel branch reactive current according to circuit power frequency resistance parameter to be measured and circuit two ends to be measured, calculates the resistance active power loss of circuit to be measured at each load measurement section;

(6) according to the nominal loss of circuit two ends to be measured shunt reactor and rated voltage parameter and circuit two ends to be measured at the line voltage effective value of each load measurement section, calculate the shunt reactor active power loss of circuit to be measured at each load measurement section;

(7) circuit to be measured is added up at the resistance active power loss of each load measurement section and shunt reactor active power loss, obtain the total active power loss of circuit to be measured at each load measurement section;

(8) circuit to be measured is carried out integral and calculating at total active power loss of each load measurement section, obtain the theory wire loss of circuit to be measured at whole calculation interval.

2. the high voltage power transmission long-line theory line loss calculation method of band shunt reactor according to claim 1, is characterized in that:

In step (4), the phase current effective value of described circuit two ends to be measured after each load measurement section compensates this side parallel branch reactive current, is obtained by following formulae discovery:

$I_{\mathrm{act}}^{\′}=\frac{U_{\mathrm{at}}}{\sqrt{3}}(\frac{\mathrm{C\ω}}{4}-\frac{1}{X_a})$

$I_{\mathrm{bct}}^{\′}=\frac{U_{\mathrm{bt}}}{\sqrt{3}}(\frac{\mathrm{C\ω}}{4}-\frac{1}{X_b})$

Wherein, I ' _at, I ' _btrepresent the phase current effective value of circuit two ends to be measured after load measurement section t compensates this side parallel branch reactive current respectively, I ' _act, I ' _bctrepresent the equivalent parallel branch road reactive current of circuit two ends to be measured at load measurement section t respectively, I _at, I _btrepresent the phase current effective value of circuit two ends to be measured at load measurement section t respectively, represent the transmission power factor angle of circuit two ends to be measured at load measurement section t respectively, U _at, U _btrepresent the line voltage effective value of circuit two ends to be measured at load measurement section t respectively, C represents line distribution capacitance parameter to be measured, and ω represents angular frequency, X _a, X _brepresent circuit two ends to be measured shunt reactor equivalent reactance respectively, Q _at, Q _btrepresent the reactive power of circuit two ends to be measured at load measurement section t respectively, P _at, P _btrepresent the active power of circuit two ends to be measured at load measurement section t respectively;

In step (5), described circuit to be measured, at the resistance active power loss of each load measurement section, is obtained by following formulae discovery:

${\mathrm{\ΔP}}_{\mathrm{Rt}}^{\′}=\frac{3R(I_{\mathrm{at}}^{\′2}+I_{\mathrm{bt}}^{\′2})}{2}$

Wherein, Δ P ' _rtrepresent the resistance active power loss of circuit to be measured at load measurement section t, R represents circuit power frequency resistance parameter to be measured;

In step (6), described circuit to be measured, at the shunt reactor active power loss of each load measurement section, is obtained by following formulae discovery:

${\mathrm{\ΔP}}_{\mathrm{Lt}}^{\′}=P_{a0}^{\′}\frac{U_{\mathrm{at}}^2}{U_{\mathrm{aN}}^2}+P_{b0}^{\′}\frac{U_{\mathrm{bt}}^2}{U_{\mathrm{bN}}^2}$

Wherein, Δ P ' _ltrepresent the shunt reactor active power loss of circuit to be measured at load measurement section t, P ' _a0, P ' _b0represent the nominal loss of circuit two ends to be measured shunt reactor respectively, U _aN, U _bNrepresent the rated voltage of circuit two ends to be measured shunt reactor respectively;

In step (7), described circuit to be measured, at total active power loss of each load measurement section, is obtained by following formulae discovery:

ΔP′ _t＝ΔP′ _Rt+ΔP′ _Lt

Wherein, Ε P ' _trepresent the total active power loss of circuit to be measured at load measurement section t;

In step (8), described circuit to be measured, at the theory wire loss of whole calculation interval, is obtained by following formulae discovery:

ΔW′＝∫ΔP′ _tdt

Wherein, Δ W ' represents the theory wire loss of circuit to be measured at whole calculation interval