High Voltage Ride-Through - Wind

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High Voltage Ride-Through of DFIG-based Wind Turbines
C. Feltes, Student Member, IEEE , S. Engelhardt, Member ,IEEE , J. Kretschmann, J. Fortmann, Member, IEEE, F. Koch, I. Erlich, Senior Member, IEEE
decoupled from the grid, the machine is directly affected by grid disturbances, which can lead to difficult operating conditions. Situations with overvoltages may arise due to load shedding or unbalanced faults. The resulting overvoltages may have different magnitudes and durations, depending on the disturbance scenario. Therefore, the international grid code requirements concerning high voltage ride-through (HVRT) slightly differ. In Australia, grid codes [4] stipulate wind turbines to withstand even an overvoltage of 1.3 p.u. for 60 ms (Fig. 1).
HVRT Requirement Australia 35.0% 30.0% Voltage in (%) 25.0% 20.0% 15.0% 10.0% 5.0% 0.0% 0.01 0.1 1 10 time in (s) 100 1000
Abstract-- With the rapid increase of large offshore wind farms in Europe, a new problem associated with the response of wind turbines to temporary overvoltages has arisen. This problem has not been a focus of discussion up to now. The majority of wind turbines use voltage source converters with a DC-link. When the grid voltage exceeds a certain limit the current flow through the line-side converter may reverse, resulting in a rapidly increasing DC voltage. To handle such situations, special countermeasures are required. This paper identifies and outlines the problem and recommends possible measures to ride through the overvoltage safely. Additionally, active voltage control structures to limit the overvoltages are proposed.
Index Terms—Wind power, control system, doubly-fed induction generator, HVRT, voltage control.
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I. INTRODUCTION
n Germany, many offshore wind farms are currently in various planning stages [1]. Since their ratings range up to several hundreds MW, they will have considerable impact on the grid. Many publications in the past discussed the reactions of wind turbines on voltage drops such as those that may appear during short circuits [2],[3]. Problems arising from situations of overvoltages were addressed by some papers, but have not yet been adequately discussed. Many wind turbine manufacturers use generators based on the concept of the Doubly-Fed Induction Machine (DFIM). These machines basically consist of a slip-ring induction generator whose rotor is connected to the grid through a back-to-back converter. The major advantage of this design is the fact that the converter does not have to be rated for the machine's full power, but only for about a third of it. However, since it is not fully
C. Feltes is with the University Duisburg-Essen, 47057 Duisburg, Germany, (email: christian.feltes@uni-duisburg-essen.de). S. Engelhardt is with Woodward SEG GmbH & Co. KG, 47906 Kempen, Germany, (e-mail: stephan.engelhardt@https://www.docsj.com/doc/46409188.html,). J. Kretschmann is with Woodward SEG GmbH & Co. KG, 47906 Kempen, Germany, (e-mail: joerg.kretschmann@https://www.docsj.com/doc/46409188.html,). J. Fortmann is with REpower Systems AG, 22768 Rendsburg, Germany, (email: j.fortmann@repower.de). F. Koch is with REpower Systems AG, 22768 Rendsburg, Germany, (e-mail: friedrich.koch@repower.de). I. Erlich is with the University Duisburg-Essen, 47057 Duisburg, Germany, (email: istvan.erlich@uni-duisburg-essen.de).
Fig. 1. HVRT Requirements in the Australian Grid Code
Overvoltages may lead to the reversal of the power flow in the line-side converter, meaning that under these conditions, current may flow from the grid into the DC-link. As a result, the DC-voltage will rise. To protect the converters, the DCvoltage has to be reduced to its rated value again. Beyond this, the current through the converter has to be limited, since IGBT’s are highly sensitive to overcurrents. Possible protection measures to ensure both limitations will be presented and discussed in the paper, followed by simulation results for illustration purposes. II. GRID CODE REQUIREMENTS Grid Code requirements on overvoltages need to take into account overvoltages resulting from the operation of a power producer or consumer as well as overvoltages originating from the grid. Obviously the grid needs to be protected from overvoltages which may arise as a result of abnormal system operating condition. Therefore it is common to set limits that
?2008 IEEE.

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enforce the disconnection of a wind turbine in case the voltage exceeds a certain limit. On the other hand, an interruption of power production resulting from transient overvoltages is not desirable. This is especially an issue of concern for transmission system operators (TSO), as the stability of the grid relies on a stable power generation. As a result, voltage control capability also of wind turbines is required by some grid operators (see Fig. 2) in order to support the voltage profile (stability). As a result the probability of disconnection of consumers and power producers in the grid can be reduced.
Additional reactive current ?IQ/IN Voltage limitation (under-excited mode)
Fig. 3. System configuration of DFIG
Within dead band, e.g. const. power factor control Activation of voltage control by exceeding dead band Continuation of voltage control after return into dead zone at least about 500 ms
Dead band around reference voltage
-50% Voltage support (over-excited mode)
-10%
10%
20%
Voltage Control characteristics
?U/UN
B. LSC control Fig. 4 shows the circuit diagram of the LSC. In a DFIG system the function of the LSC is to maintain the DC voltage and provide reactive current support for optimization of the reactive power sharing of MSC and LSC. During grid faults additional short-time reactive power can be fed to support the grid. Especially when the machine rotor is short circuited through the crowbar resistors, the generator consumes reactive power. This reactive power has to be compensated by the LSC.
Reactive_current/voltage gain: k=?IQ/?U 2.0 p.u.
≥
Rise time < 20 ms -100% Maximum available reactive current IQ_max = IN
Fig. 2. Reactive power requirements of E.ON Netz [5] for HVRT.
III. WIND TURBINES A. Hardware System The most commonly used generator type in modern wind turbines is the DFIG. A typical layout of a DFIG system is shown in Fig. 3. The back-to-back frequency converter in combination with pitch control of the rotor blades enable variable speed operation, leading to higher energy yields compared to fixed speed wind turbines. Since the IGBTconverter is located in the rotor circuit, it only has to be rated to a small portion of the total generator power (typically 2030%, depending on the desired speed range). A rotor crowbar is used to protect the rotor side converter against overcurrents and the DC capacitors against over-voltages during grid faults. But a crowbar ignition means the loss of the generator controllability through the machine side converter (MSC), since the machine rotor is short-circuited through the crowbar resistors and the MSC is blocked. During this time slot the generator acts as a common induction generator and consumes reactive power, which is not desirable for LVRT. During HVRT a crowbar ignition would lead to a high generator torque and uncontrolled active and reactive power output. To avoid a crowbar ignition for most fault scenarios, a DC chopper is used to limit the DC voltage by short-circuiting the DC circuit through the chopper resistors. A line inductor and an AC filter are used at the grid side converter to improve the power quality.
Fig. 4. LSC circuit
The control structure of the LSC is shown in Fig. 5 and Fig. 6. The outer loop of the LSC control features dc-link voltage control and reactive power control by controlling active and reactive current of the LSC [6]. The performance of the voltage controller can be enhanced by a feed-forward control of the active current of the MSC, which can be calculated via the MSC active power and the line voltage. The magnitude of the current set value is limited according to the converter rating with a priority for the active current to ensure correct dc-link voltage control. With the voltage drop across the grid reactor considered, the resulting converter voltage is: d i ∠ug ug ∠ug ug (1) u∠ ? l LSC ? jω0l ? i ∠ LSC = u G LSC dt ∠ug , In a voltage oriented reference frame ( u G ,q = 0
∠ug ∠ug ) the dq-components of the LSC voltages are: uG ,d = u G,d ∠ug ∠ug u LSC , d = u G ,d ? l ∠ug diLSC ,d ∠ ug + ω0l ? iLSC ,q
dt
(2)
∠ug (3) ? ω0l ? iLSC ,d dt From eq. (2) and (3) the inner current control loop in Fig. 6. can be easily derived. The cross-coupling terms of the voltage across the grid reactor and the grid voltage are fed forward so
∠ug u LSC , q = ?l
∠ug diLSC ,q

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that the PI-controllers only have to provide a fast transition of the current to the respective set-values.
u DC _ ref
? ?1 + KP? ?
pWT _ ref
1 pTI
? ? ? ?
∠ug iLSCd _ ref
1 1 + pT1
pLSC
pS _ ref
xS xh
uS
÷
∠u S i Rd _ ref
u DC
pR
uG
÷
-
magnitude limitation with active current priority
∠ug iLSCq _ ref
qWT _ ref
qS _ ref
magnitude limiter
1 1 + pT2
qLSC
xS xh
uS
÷
1 xh
uS
∠u S i Rq _ ref
u AC _ ref
u AC
-
reactive current characteristic
∠ug iLSCq _ ref *
Fast local voltage controller
u
1 1 + pT1
u
-
KVC
Fig. 5. DC voltage and reactive power control at LSC
uGd
∠ug iLSCd _ ref
∠ug iLSCd
? KP ? ?1 + ?
Fig. 7. Generator active and reactive power
-
1 pTI
? ? ? ?
-
u
∠ug LSCd _ ref
∠u S i Rd _ ref
∠u S iRd
? KI ? ?1 + ?
1 pTI
? ? ? ?
∠u S u Rd
ωL ωL
-
∠ug iLSCq
∠ug iLSCq _ ref
? ?
magnitude limitation with active power priority
s s
∠u S u S iRq
∠u S s i Rd σ xR
KP? ?1 +
1 pTI
? ? ? ?
-
-
u
∠ug LSCq _ ref
s
uGq
Fig. 6. LSC current control
? ? ? ?
? xh ∠u S u S ? i Rq σ xR ? ? xS ?
r e it m li e d u it n g a M
u
x a m _ R
∠u S i Rq _ ref
C. MSC control The MSC controls active and reactive power of the DFIG and follows a tracking characteristic to adjust the generator speed for optimal power generation depending on wind speed. Optionally a fast local voltage controller can be implemented. The cascaded control structure of the MSC is shown in Fig. 7 and Fig. 8 [7]. The outer power control loop of the MSC adjusts the rotor current set values of the inner rotor current loop. The fundamental system of equations for the DFIG in the synchronous reference frame linked to the stator voltage is given by the following equations: Voltage equations: dψ S (4) u S = rS i S + + jω S ψ S
u R = rR i R +
dt dψ R
? KI ? ?1 + ?
1 pTI
? ? ? ?
∠u S u Rq
Fig. 8. MSC current control
The equations for the feed-forward current control can be derived considering steady state operation and neglecting the stator resistance: dψ S dψ R (9) = =0
dt rS = 0 dt
(10)
After some algebraic manipulations one obtains the complex state equation for the steady state rotor voltage:
uR = s xh ? u S ? jsσx R i R xS
dt
+ j (ω S ? ω R )ψ R
(5) (6) (7) (8)
Flux equations: ψ S = l S i S + lh i R
ψ R = lh i S + l R i R
(11) By forwarding this voltage the parallel PI current controllers only have to put into effect the transition of the rotor currents to the set values and compensation for the stator resistance. The corresponding current control loops are shown in Fig. 8. The equations for the power are: (12) pWT = p S + p LSC
qWT = q S + q LSC
Equation of motion: 1 dω R = (ψ i ?ψ SqiSd + tm ) dt θ m Sd Sq
pS = Re u i qS
Taking into account eq. (4),(6),(9) and (10) we receive with (16) i R = iRd + jiRq
{ } = Im{ u i }
* s S * s S
(13) (14) (15)

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xh u S iRd xS x 1 2 qS = u S + h u S iRq xS xS pS = ?
(17) (18)
From eq. (17) and (18) the feed-forward terms of the outer power control loop shown in Fig. 7 can be derived. IV. HIGH VOLTAGE RIDE-THROUGH To guarantee a safe operation of the WT during HVRT it has to be ensured that the converters always work in their permissible voltage range. The maximum available converter voltage, which can be modulated from the DC voltage, is: 3 ? U DC (19) uconv,max = mmax 2 2 ?U LSCn During HVRT different problems may arise from the increased voltages at LSC and MSC. These problems require adequate solutions in the converter control and will be discussed separately for LSC and MSC in the following.
A. HVRT with LSC Fig. 4 can be used to elucidate the effect of an overvoltage in the grid on the LSC. During HVRT the grid voltage may exceed the maximum converter voltage. To avoid over modulation the converter voltages have to be limited: 2 2 (20) u LSC = u LSC ,d + u LSC ,q ≤ uconv , max It has to be guaranteed that the active current can always be controlled to maintain the DC voltage. Thus, the limitation of converter output voltage has to consider a priority for active current i ∠ug that, however, is proportional to the qcomponent of the LSC voltage as can be seen from Fig. 9. Therefore only the d-component of the LSC voltage has to be limited while keeping the q-component unchanged:
∠ug 2 2 ∠ug u LSC uconv , d ,lim = , max ? u LSC , q
LSCd
With the derived converter voltage limitation the LSC control enables secure HVRT up to a voltage level, which mainly depends on the maximum converter current and the critical current of the grid reactor that may lead to saturation. But the LSC voltage limitation derived so far can only provide good results for symmetrical HVRT, because un-symmetrical voltage components have not been considered. To extend the LSC control for unsymmetrical overvoltages, another term representing the magnitude of the negative sequence part of the grid voltage has to be considered in the converter output voltage limitation: 2 2 ∠ug ∠ug (23) u LSC u conv , d ,lim = , max ? u LSC , q ? u G , 2 This modification ensures that the negative sequence component in the measured grid voltage, which is included as feed-forward term in the LSC current control, is not shaved by the output limitation. This way the negative sequence component in the LSC currents is minimized to reduce the DC voltage ripple during unsymmetrical operation [8]. This term can be obtained from the measured grid voltage by sequence separation through coordinate transformation into a reference system rotating with the negative sequence system and filtering out the positive sequence components with a lowpass filter. It also has to be considered in the reactive current setpoint of the LSC. B. HVRT with MSC The requirements for the MSC are similar to those derived for the LSC. But since the MSC is not directly connected to the grid but to the rotor circuits of the generator, the voltage magnitude and frequency at the MSC during HVRT strongly depend on the operating point of the machine. To evaluate the effect of overvoltages to the MSC, the machine equations (section III. C. ) have to be considered. From eqn. (11) it is apparent, that the impact of a HVRT to the MSC not only depends on the stator voltage magnitude, but also on the machine slip. I.e., in the normal speed range of the generator the induced rotor voltage is smaller than the maximum converter voltage, even during HVRT. HVRT may only become critical for the MSC, when the generator is operated close to the speed limits. During normal voltage operation the MSC control works with active current priority to guarantee that the generator can track the active power set points provided by the supervisory control. Usually, in this mode the voltage limitation of the MSC is not active. During fault (LVRT or HVRT) the priority is switched to the reactive current to ensure that the WT can fulfill the voltage support requirements stipulated by the grid codes. In case of HVRT this means that the generator moves to the underexcited mode. The minimum requirement in the German grid codes for the voltage controller is a proportional gain of 2.0 p.u., but for a better voltage reduction higher gains are recommended. When the induced rotor voltage becomes bigger than the maximum converter output voltage, theMSC voltage is limited by a magnitude limiter. In case of unsymmetrical voltages the MSC can also be used to suppress the negative sequence component in the machine currents. But the negative sequence voltage components
(21)
∠ug xiLSCq
u LSC i LSC
∠ug iLSCd ∠ug
∠ug
jxi LSC
∠ug jiLSCq
∠ug
∠ug jxiLSCd
uG
∠ug
uconv,max
Fig. 9. Phasor diagram of LSC voltages and currents for HVRT
To avoid undesired actions of the LSC current controllers, the current due to the limitation 1 ∠ug ∠ug (22) i LSCq (u ∠ug ? uG _ ref * = ,d ) ωL LSC ,d ,lim is fed back and used as new setpoint for the q-axis current controller (Fig. 5). Additionally the controller state variables are held, when the voltage limitation is active.

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induced through the machine are amplified from the stator to the rotor side with negative sequence slip: ω + ωR (24) sneg = 0 ω0 Additionally, the turns ratio of the generator also amplifies voltages from stator to rotor side. As a result, the negative sequence control of the MSC is strongly limited. In any case, since the MSC does not participate in DC voltage control, the only reason to implement a negative sequence control at the MSC would be to reduce oscillating torques on the drive train. But this control would adapt the negative sequence component of the stator voltage to the grid voltage, meaning that the voltage imbalance is accepted without countermeasures. Without this control the negative sequence is short circuited in the generator like in the damper winding of a synchronous generator. From grid point of view this is desirable, since the resulting negative sequence currents contribute to balancing stator voltages [9]. V. SIMULATION All simulation studies presented in this paper have been done with MATLAB/ Simulink with use of the SimPowerSystems Toolbox. The generators are represented by a fourth-order model of the electrical circuit and the mechanical part is neglected due to the small speed deviation during the time period considered. Therefore, the simulations were carried out with constant rotor speed. The IGBT converters are modeled as ideal switches with anti-parallel diodes. Distributed parameter models are used for lines and the transformer models consider saturation effects, but no hysteresis. Circuit breaker models are ideal and open exactly at the first current zero crossing after the open command. For the simulation scenarios a 200 MW wind farm is modeled by two equivalent wind turbines in scenario A and by one equivalent wind turbine in scenario B. In scenario A two wind turbine equivalents are used, because one is tripped after a three-phase fault while the behaviour of the other is studied during voltage recovery. The wind turbines are connected at 36kV level to a step-up transformer, whose primary side is connected to the 150 kV sea cable with a cross section of 1200 mm2 and a length of 100 km. Shunt reactors are installed at both sides of the cable. The transmission system is connected to the extra-high voltage grid through a 150/380 kV transformer. Fig. 10 shows the observed test system.
HV Grid 400 kV 19.75 GVA X/R=8 Transformer 380/150 kV 270 MVA uk=16% 150 kV Sea Cable 100 km R’=0.0208 ?/km X’=0.1012 ?/km C’=0,229 μF/km Transformer 150/36 kV 270 MVA uk=14% Wind Farm Equivalent 200 MW
A. Symmetrical HVRT In the symmetrical HVRT scenario the wind farm is operating at nominal power at a generator speed of 1.25 p.u. All generators are working in underexcited mode, when a severe three-phase fault of 200 ms duration occurs in the wind farm grid. After switching off the faulty line the voltage recovers (Fig. 11). But since 75% of the wind turbines have been tripped the voltage does not return to its pre-fault value but to a steady-state value of approx. 115% with HVRT control and to approx. 120% without HVRT control. The overshoot after fault clearing brings along a transient peak voltage of approx. 130% for both cases. From Fig. 11 it can be seen that the wind turbines support the grid voltage during and after fault through the provision of reactive power. When the fault occurs, the wind turbines change from underexcited to overexcited mode for LVRT voltage support and after voltage recovery they are operating in underexcited mode again to reduce the grid voltage in HVRT mode. The reactive power support is shared between stator and LSC to limit the LSC output voltage according to section IV. A. . During transient voltage recovery the active power at the LSC is reversed, leading to an increased DC voltage. This can be handled by a well-designed DC chopper, which limits the DC voltage to approx. 1.05 p.u. B. Unsymmetrical HVRT One situation which can lead to unsymmetrical overvoltage is a single-phase short-term interruption (STI). In the simulated case the wind farm is operating at nominal load, when a single phase short circuit occurs in the HV grid, which lasts for 100 ms and is followed by a STI at the PCC. After 200 ms the line is switched on again. Normally a STI cycle is longer, but a shorter period has been chosen here for observation. Fig. 12 shows the simulation results. The positive sequence component of the grid voltage drops to approx. 75% during fault and recovers during STI with a dampened oscillation with a large overshoot of approx. 133%. The negative sequence voltages during STI are slightly bigger than during fault and show the same oscillations as the positive sequence components. In comparison with the negative sequence voltage at MV grid and generator stator it becomes obvious, that the generator has a balancing effect on the stator voltage. The impact of the fault and STI on the WT active power is rather small compared to symmetrical fault and the oscillations are well dampened. The oscillations in positive sequence reactive power correlate with the voltage oscillations and are small in scope. The main oscillations are in the distribution between stator and LSC reactive power. The negative sequence active and reactive power diagrams show the generator acting as a resistive inductive load for the negative sequence, which reflects the balancing effect of the generator to the stator voltages.
Shunt Reactors 150 kV 2 x 60 MVA Fig. 10. Test grid

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1.5
MV grid voltages (p.u.)
without voltage control with voltage control
1.0
voltage range. When the phase with the STI is switched on again, there is a peak in the stator power and respectively in the rotor power, which leads to a small overshoot in the DC voltage, which is handled by the DC chopper.
0.5
1,5
Positive sequence voltages (p.u.)
0.0
2.0 1.0 0.0 -1.0 -2.0 -3.0 -4.0 2.0 1.0 0.0
Active and reactive power at MV grid (p.u.)
Q
1,0
U1_MV U1_stator U1_LSC
P
0,5 0,4 0,3 Negative sequence voltages (p.u.)
U2_MV U2_stator U2_LSC
Stator active and reactive power (p.u.)
Q
0,2 0,1
P
-1.0 -2.0 -3.0
1.0 LSC active and reactive power (p.u.)
0,0 1,0 Positive sequence active power (p.u.)
0,0
-1,0
0.5
Q
-2,0
1.0 Positive sequence reactive power (p.u.)
P1_MV P1_stator P1_LSC
0.0
-0.5
1.1 DC voltage (p.u.)
P
0.5 0.0 -0.5
Q1_MV Q1_stator Q1_LSC
1.0
-1.0
0.3 0.4 0.5 0.6 0.7 0.8 0.9
time (s)
time (s)
1
0.9 0.3 0.5 0.7 0.9 1.1
Fig. 11. Simulation results for symmetrical HVRT
1.3
In addition to positive and negative sequence components the active and reactive power also contain components oscillating with 100 Hz, which result from the interaction of positive and negative sequence components [10]. As a result of these power oscillations at MSC and LSC, there is also a 100 Hz ripple in the DC voltage. This ripple is in the allowable

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0,2
Negative sequence active power (p.u.)
0,1
P2_MV P2_stator P2_LSC
0,0
-0,1
0,5 0,4 0,3 0,2 0,1 0,0 -0,1 1,1
Negative sequence reactive power (p.u.)
countermeasures in the MSC control. It reduces the negative sequence components in the stator and grid voltages by shortcircuiting the negative sequence. The torque oscillations, which occur during unsymmetrical HVRT are acceptable, since the time period of the voltage disturbance is short. The enhanced LSC control for HVRT reduces the LSC negative sequence currents to reduce the 100 Hz ripple in the DC voltage and to avoid undesired chopper actions. From those facts it can be concluded, that the proposed control provides a good and secure solution for HVRT from both generator and grid point of view.
Q2_MV Q2_stator Q2_LSC
VII. REFERENCES
Bundesverband Windenergie e.V., [online], Available: http://www.windenergie.de [2] I. Erlich, H. Wrede, C. Feltes, ?Dynamic Behavior of DFIG-Based Wind Turbines during Grid Faults”, Power Conversion Conference, IEEE 2007. PCC Nagoya '07 [3] A. Geniusz, S. Engelhardt, “Riding through Grid Faults with Modified Multiscalar Control of Doubly Fed Asynchronous Generators for Wind Power Systems”, Records of the PCIM Conference, Nürnberg, 2006 [4] AEMC, “National Electricity Rules Version 13”, march 2007, online: https://www.docsj.com/doc/46409188.html,.au [5] Eon Netz GmbH, “Grid Code High and Extra high voltage”, online: https://www.docsj.com/doc/46409188.html,/, Bayreuth, 2006 [6] R. Pena, J. C. Clare, G. M. Asher, “Doubly fed induction generator using back-to-back PWM converters and its application to variable-speed windenergy generation”, in Proc. 1996 IEE Electric Power Applications [7] I. Erlich, J. Kretschmann, J. Fortmann, et al., “Modeling of Wind Turbines based on Doubly-Fed Induction Generators for Power System Stability Studies”, presented at Power Systems Conference and Exhibition, Atlanta 2006 [8] Müller-Engelhardt, S.;Wrede, H.; Kretschmann, J.: ?Leistungsregelung von Windkraftanlagen mit doppeltgespeister Asynchronmaschine bei Netzunsymmetrie.“ S. 489–500, VDI-Fachberichte 1963 Elektrischmechanische Antriebssysteme, VDIVerlag, 2006 (ISBN 3-18-091963-9) [9] Engelhardt, S.: Regelung von Frequenzumrichtern für Windenergieanlagen mit doppelt gespeistem Asynchrongenerator, S.92110, ISET Tagungsband Zw?lftes Kasseler Symposium EnergieSystemtechnik, Regelungstechnik für dezentrale Energiesysteme, 22.23.11.2007 [10] Hong-Seok Song, Kwanghee Nam, ?Dual Current Control Scheme for PWM Converter Under Unbalanced Input Voltage Conditions“, IEEE Transactions on Industrial Electronics, Vol. 46, October, 1999 [1]
DC voltage (p.u.)
1,0
0,9 0,3 0,4 0,5 0,6 0,7 0,8 0,9
Fig. 12. Simulation results for unsymmetrical HVRT
time (s)
1
VI. CONCLUSION In this paper the problems, which may occur during HVRT were discussed and suitable solutions for the converter control were presented. During HVRT with the standard control the power flow at the LSC may reverse, which would lead to a fast increase of the DC voltage in the converter. With the proposed enhanced HVRT control for the LSC the power flow into the DC circuit can be reduced. This is done by a converter output voltage limitation considering active current priority, which causes the LSC to operate in underexcited mode during HVRT. With this solution the activity of the DC chopper can be reduced. The simulation results for symmetrical HVRT show that the voltage control of the DFIG drives the generator into underexcited operation mode, leading to a reduction of the grid overvoltage. A comparison with the same scenario without the voltage control confirms this statement and shows differences in the MV voltage of approx. 5%. The voltage control presented here only acts when the fault effects a change of more than 10% of the nominal voltage. A continuous voltage control, like the one stated in the E.ON grid code, should be considered in future studies, since small voltage disturbances will also be covered. The unsymmetrical scenario shows that the generator has a balancing effect on the stator voltages without any special

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Jens Fortmann (1966) received his Dipl.-Ing. degree in electrical engineering from the Technical University Berlin, Germany, in 1996. From 1995 to 2002 he worked on the simulation of the electrical system and the control design of variable speed wind turbines at the German wind turbine manufacturers Suedwind and Nordex Energy. Since 2002 he is with REpower Systems AG, Germany as project manager for the simulation and implementation of new technologies for improved grid compatibility of wind turbines like voltage control and ridethrough of grid faults. He is member of IEEE. Friedrich W. Koch (1969) received his Dipl.-Ing. degree in electrical engineering from the University of Siegen, Germany in 1998. From 1998 to 2000 and 2005 to 2006 he worked as engineer, project manager and finally as head of group in the field of industrial and power plants for the SAG GmbH. In between from 2000 to 2005 he worked on his PhD in the Department of Electrical Power Systems at the University of Duisburg Essen, Germany. Since 2006 he is with REpower Systems AG, Germany as head of the group "Grid Integration / Simulation". Istvan Erlich (1953) received his Dipl.-Ing. degree in electrical engineering from the University of Dresden/Germany in 1976. After his studies, he worked in Hungary in the field of electrical distribution networks. From 1979 to 1991, he joined the Department of Electrical Power Systems of the University of Dresden again, where he received his PhD degree in 1983. In the period of 1991 to 1998, he worked with the consulting company EAB in Berlin and the Fraunhofer Institute IITB Dresden respectively. During this time, he also had a teaching assignment at the University of Dresden. Since 1998, he is Professor and head of the Institute of Electrical Power Systems at the University of DuisburgEssen/Germany. His major scientific interest is focused on power system stability and control, modelling and simulation of power system dynamics including intelligent system applications. He is a member of VDE and senior member of IEEE.
VIII. BIOGRAPHIES
Christian Feltes (1979) received his Dipl.-Ing. degree in electrical engineering from University of DuisburgEssen/Germany in 2005. Since January 2006 he is doing his Ph.D. studies in the Department of Electrical Power Systems at the same University. His research interests are focused on wind energy generation, control, integration and dynamic interaction with electrical grid. He is student member of IEEE. Stephan Müller-Engelhardt (1967) received his Dipl.Ing. degree in electrical engineering from the University Hannover, Germany, in 1997. Since 1997 he is with SEG GmbH & Co. KG, Kempen/Germany, presently manager of the group Innovation / Converter Technology and responsible for system designs and simulations, control strategies and patents. He is a member of IEEE.
J?rg Kretschmann (1958) received his Dipl.-Ing. degree in electrical engineering from the Technical University Berlin, Germany, in 1986. In the period of 1986 to 1988 he worked for engineering department of AEG-Kanis in Essen, manufacturing of synchronous generators up to 200 MVA. Since 1988 he is with SEG GmbH & Co. KG, Kempen/Germany, as a designing engineer for speedvariable applications: uninterruptible power supply, shaft alternators, DFIG for wind turbines. His main field is simulation of power converter systems, design of power components, passive grid-filter.

财务报表指标计算公式

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财务指标计算公式(超全)

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财务指标的计算公式

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常用财务指标计算公式

常用财务指标计算公式、分析和解释 一、偿债能力指标分析 （一）短期偿债能力分析 企业短期偿债能力的衡量指标主要有流动比率、速动比率和现金流动负债比率。 1.流动比率 流动比率=流动资产/流动负债 意义：体现企业的偿还短期债务的能力。流动比率越高，说明企业短期偿债能力越强。国际上通常认为，流动比率的下限为100%，流动比率等于200%时较为适当。 分析提示：低于正常值，企业的短期偿债风险较大。一般情况下，营业周期、流动资产中的应收账款数额和存货的周转速度是影响流动比率的主要因素。 2.速动比率 速动比率=速动资产/流动负债 意义：速动比率越高，表明企业偿还流动负债的能力越强。因为流动资产中，尚包括变现速度较慢且可能已贬值的存货，因此将流动资产扣除存货再与流动负债对比，以衡量企业的短期偿债能力。通常认为，速动比率等于100%时 较为适当。 分析提示：低于1的速动比率通常被认为是短期偿债能力偏低。影响速动比率的可信性的重要因素是应收账款的变现能力，账面上的应收账款不一定都能变现，也不一定非常可靠。 3.现金流动负债比率 现金流动负债比率=年经营现金净流量/年末流动负债 意义：该指标越大，表明企业经营活动产生的现金净流量越多，越能保障企业按期偿还到期债务。 短期偿债能力分析总提示： （1）增加变现能力的因素：可以动用的银行贷款指标；准备很快变现的长期资产；偿债能力的声誉。 （2）减弱变现能力的因素：未作记录的或有负债；担保责任引起的或有负债。 （二）长期偿债能力分析 企业长期偿债能力的衡量指标主要有资产负债率、产权比率

1.资产负债率 资产负债率=负债总额/资产总额 意义：反映债权人提供的资本占全部资本的比例。该指标也被称为举债经营比率。资产负债率越小，表明企业长期偿债能力越强。 分析提示：负债比率越大，企业面临的财务风险越大，获取利润的能力也越强。如果企业资金不足，依靠欠债维持，导致资产负债率特别高，偿债风险就应该特别注意了。资产负债率在55％—65％，比较合理、稳健；达到80％及以上时，应视为发出预警信号，企业应提起足够的注意。 2.产权比率 产权比率=负债总额/所有者权益总额 意义：反映债权人与股东提供的资本的相对比例。反映企业的资本结构是否合理、稳定。同时也表明债权人投入资本受到股东权益的保障程度。 分析提示：一般说来，产权比率高是高风险、高报酬的财务结构，产权比率低，是低风险、低报酬的财务结构。从股东来说，在通货膨胀时期，企业举债，可以将损失和风险转移给债权人；在经济繁荣时期，举债经营可以获得额外的利润；在经济萎缩时期，少借债可以减少利息负担和财务风险。 二、营运能力指标分析 生产资料营运能力分析 生产资料的营运能力实际上就是企业的总资产及其各个组成要素的营运能力。资产营运能力的强弱关键取决于资产的周转速度，通常用周转率和周转期来表示。周转率是企业在一定时期内资产的周转额与平均余额的比率，它反映企业资产在一定时期的周转次数。周转期是周转次数的倒数与计算期天数的乘积，反映资产周转一次所需要的天数。其计算公式为： 周转率（周转次数）=周转额÷资产平均余额 周转期（周转天数）=计算期天数÷周转次数 =资产平均余额×计算期天数÷周转额 具体地说，生产资料营运能力分析可以从以下几个方面进行分析。 1.应收账款周转率 应收账款周转率（周转次数）=主营业务收入净额/平均应收账款余额 主营业务收入净额=主营业务收入-销售折扣与折让 平均应收账款余额=（应收账款余额年初数+应收账款余额年末数）÷2 意义：应收账款周转率越高越好。应收账款周转率高，表明收账迅速，账龄较短；资产流动性强，短期偿债能力强；可以减少收账费用和坏账损失。 分析提示：应收账款周转率，要与企业的经营方式结合考虑。以下几种情况使用该指标不能反映实际情况：第一，季节性经营的企业；第二，大量使用分期收款结算方式；第三，大量使用现金结算的销售；第四，年末大量销售或年末销售大幅度下降。

财务经济指标计算公式

财务经济指标计算公式 1、流动比率=流动资产合计/流动负债合计*100% 2、速动比率=速动资产/流动负债。速动资产是指流动资产扣除存货之后的余额, 3、现金流动负债比率=年经营现金净流量/年末流动负债×100% 4、资产负债率=（负债总额/资产总额）*100％。 5、产权比率也称资本负债率=负债总额/所有者权益总额*100% 6、或有负债比率=或有负债余额/所有者权益总额*100% 或有负债余额=已贴现商业承兑+对外担保+未决诉讼、未决仲裁（除贴现与担保引起的诉讼与仲裁）+其他或有负债。 7、已获利息倍数=息税前利润总额/利息支出。 其中：息税前利润总额=利润总额+利息支出。利息支出，实际支出的借款利息、债券利息等。 8、带息负债比率=（短期借款+一年内到期的长期负债+长期借款+应付债券+应付利息+）/负债总额*100%。 9、劳动效率=营业收入或净产值/平均值工人数 10、生产资料运营能力： 周转率=周转额÷资产平均余额； 周转期=计算期天数÷周转次数。=资产平均余额*计算期天数/周转额 11、应收账款周转率（次）=销售收入÷平均应收账款 周转数（周转天数）=计算期天数/周转次数=资产平均余额*计算期天数/周转额12、①存货周转率(次)＝销售成本÷存货平均余额②存货周转天数=计算期天数/存货周转次数

13、流动资产周转率（次）=主营业务收入净额/平均流动资产总额X100% 14、固定资产周转率（次数）=营业收入÷平均固定资产净值 固定资产周转期（天数）=平均固定资产净值×360/营业收入。 15、总资产周转率（次）=营业收入÷平均资产总额。 16、不良资产比率=（资产减值准备余额+应提未提和应摊未摊的潜亏挂账+未处理资产损失）÷（资产总额+资产减值准备余额）。 17、资产现金回收率=经营现金净流量/平均资产总额。 18、营业利润率=营业利润/营业收入(商品销售额)×100% 19、销售净利率=净利润÷销售收入*100%。 20、销售毛利率=（销售收入-销售成本）÷销售收入*100% 21、成本费用利润率=利润总额/成本费用总额×100% 式中的利润总额和成本费用用总额来自企业的损益表。成本费用一般指主营业务成本和三项期间费用 营业税金及附加。 22、盈余现金保障倍数＝经营现金净流量／净利润 23、总资产报酬率=（利润总额+利息支出）/平均资产总额X100%， 息税前利润总额=利润总额+利息支出 24、加权平均净资产收益率＝报告期净利润÷平均净资产×100% 25、资本收益率又称资本利润率 资本收益率= 税后净利润/平均所有者权益 26、基本每股收益率=归属于普通股东的当期净利润/当期发行在外普通股的加权平均数；

财务报表计算公式大全

计算公式部分第一章： 1.变动百分比=分析项目金额—分析基准金额 分析基准金额 ×100% P19 2.构成比率=某项指标值 总体值 ×100% P23 3.定比动态比率= 分析期数额 固定基期数额 ×100% P28 4.环比动态比率=分析期数额 前期数额 ×100% P28 第二章： 5.营运资本=流动资产—流动负债。 P127 6.流动比率=流动资产 流动负债 P129 7.流动比率=（流动资产—流动负债）+流动负债 流动负债 P129 8.流动比率=营运资金+流动负债 流动负债 P129 9.流动比率=1+ 营运资金 流动负债 P129 注：（6—9流动比率的计算公式）中流动资产包括：货币资金、短期投资、应收票据、应收账款、其他应收款、存货等。流动负债包括：短期借款、应付票据、应付账款、其他应付款、应付利息、应付股利、应付税费、应付职工薪酬等。其中，流动资产通常指流动资产净额。 10.速动比率=速动资产 流动负债 P133

11.速动资产=货币资金+短期投资+应收票据+应收账款+其他应收款 P134 第五章： 12.现金比率=现金+短期有价证券 流动负债 P137 13.资产负债率=负债总额 资产总额 P144 14.股权比率=所有者权益总额 资产总额 P147 15.资产负债率+股权比率=负债总额+所有者权益总额 资产总额 ×100% P147 16.资产负债率+股权比率=负债总额 资产总额 ×100% + 所有者权益总额 资产总额 ×100% P147 17.资产负债率+股权比率=100% P147 18.股权比率=1—资产负债率。 P148 19.产权比率= 负债总额 所有者权益总额 ×100% P149 20.产权比率= 负债总额/资产总额 所有者权益总额/资产总额 == 资产负债率 股权比率 P149 21.产权比率=资产总额—所有者权益总额 所有者权益总额 = 1 股权比率 —1 P149 22.权益乘数= 资产总额 所有者权益总额 P150 23.权益乘数=负债总额+所有者权益总额 所有者权益总额 P150 24.权益乘数=1+产权比率 P150 25.权益乘数= 资产总额 所有者权益总额 = 1 股权比率 P151

主要财务指标计算公式

主要财务指标计算公式 （一）偿债能力指标 偿债能力是指企业清偿短期、长期债务的能力。 1、资产负债率 资产负债比率=负债总额 /资产总额 一般认为，该比率维护在40-60%之间较为合适，负债比率过高是不利的，应引起重视。 2、流动比率 流动比率=流动资产总额/流动负债总额 它反映企业短期负债的清偿能力，即每1元流动负债额中有多少流动资产额作保证。一般认为2:1的流动比率较好。若该比率过低，说明企业偿还能力较差，若该比率过高，说明企业的部分资金闲置。 3、速动比率 速动比率=流动资产总额-存货 /流动负债总额 因为存货不能马上形成支付能力，所以速动比率比流动比率更能准确反映企业的偿债能力。一般认为，该比率为1:1较好。 4、现金比率 反映企业即时偿还流动负债的能力，指标计算公式如下： 现金比率=（货币资金+三个月到期的短期投资和应收票据）/流动负债 现金比率越高，说明公司的短期偿债能力越强。 5、利息保障倍数 衡量企业偿还借款利息的能力，指标计算公式如下（如不能得到利息费用的详细资料，可用“财务费用”代替“利息费用”）： 利息保障倍数=（利润总额+利息费用）/利息费用 利息保障倍数指标反映出企业的经营所得保障支付负债利息的能力，它的倍数一般情况下应大于1，同时应选择5年中最低的比率作为最基本的偿付利息能力指标，否则就难以偿还债务及利息。但从短期看，由于折旧费、摊销费及折耗费等短期内不需要支付资金，所以利息保障倍数小于1时，企业通常也能偿还其利息债务。 6、应收账款损失率 应收账款损失率=坏账损失/应收账款总额 一般讲该指标越小越好，比率高应引起重视，必须到企业对应收帐款进行调查，找出原因。 7、经营活动产生的现金流量 反映企业以经营活动现金流入偿还债务的能力。（1）将销售商品、提供劳务收到的现金与购进商品、接受劳务付出的现金进行比较。在企业经营正常、购销平衡的情况下，二者比较的比率大，说明企业的销售利润大，销售回款良好，创现能力强。（2）将销售商品、提供劳务收到的现金与经营活动流入的现金总额进行比较，可大致说明企业产品销售现款占经营活动流入的现金的比重。比重大，说明企业主营业务突出，营销状况良好。（3）将本期经营活动现金净流量与上期进行比较，增长率越高，说明企业成长性越好。 （二）营运能力指标 1、应收账款周转率 反映了应收账款周转速度，及时收回应收账款，不仅能增强企业的短期偿债能力，也能反映出企业管理应收账款方面的效率。用时间表示的周转速度是应收账款周转天数，也叫平均应收账款回收期或平均收现期，其计算公式为：

英文财务指标及计算公式汇总

Ratios Profitability ratios Profitability ratios measure the firm's use of its assets and con trol of its expe nses to gen erate an acceptable rate of return. Gross margin. Gross profit margin or Gross Profit Rate Gross Profit Net Sales OR S吐s - GOGS Net. Sales Operat ing margin, Operat ing In come Margin, Operat ing profit margin or Retur n on sales (ROS) Operating Income Net Sales Note: Operati ng in come is the differe nee betwee n operati ng reve nues and operat ing expe nses, but it is also sometimes used as a synonym for EBIT and operating profit. [10] This is true if the firm has no non-operati ng in come. (Ear nings before in terest and taxes / Sales) Profit margin, net margin or net profit margin Ntit Income Net Sales Return on equity (ROE) Net Income Average SharcholdeTS Equity Retur n on in vestme nt (ROI ratio or Du Pont ratio) Net Income Average Owmeis Equity Retur n on assets (ROA) Net Income Tot EL I Assets Return on assets Du Pont (ROA Du Pont) (Net Income f Net Sales \ \

财务指标计算公式

财务指标计算公式 一、常用财务指标一般分类及计算 一、偿债能力指标 （一）短期偿债能力指标 1.流动比率=流动资产÷流动负债 2.速动比率=速动资产÷流动负债 3.现金流动负债比率=年经营现金净流量÷年末流动负债×100% （二）长期偿债能力指标 1.资产负债率=负债总额÷资产总额 2.产权比率=负债总额÷所有者权益 二.营运能力指标 (一)人力资源营运能力指标 劳动效率=主营业务收入净额或净产值÷平均职工人数 (二)生产资料营运能力指标 1.流动资产周转情况指标 (1)应收账款周转率(次)=主营业务收入净额÷平均应收账款余额 应收账款周转天数=平均应收账款×360÷主营业务收入净额 (2)存货周转率(次数)=主营业务成本÷平均存货 存货周转天数=平均存货×360÷主营业务成本 (3)流动资产周转率(次数)=主营业务收入净额÷平均流动资产总额 流动资产周转期(天数)=平均流动资产总额×360÷主营业务收入净额 2.固定资产周转率=主营业务收入净额÷固定资产平均净值 3.总资产周转率=主营业务收入净额÷平均资产总额 三.盈利能力指标 (一)企业盈利能力的一般指标 1.主营业务利润率=利润÷主营业务收入净额 2.成本费用利润率=利润÷成本费用 3.净资产收益率=净利润÷平均净资产×100% 4.资本保值增值率=扣除客观因素后的年末所有者权益÷年初所百者权益×100% (二)社会贡献能力的指标 1.社会贡献率=企业社会贡献总额÷平均资产总额 2.社会积累率=上交国家财政总额÷企业社会贡献总额 四.发展能力指标 1.销售(营业)增长率=本年销售(营业)增长额÷上年销售(营业)收入总额×100% 2.资本积累率=本年所有者权益增长额÷年初所有者权益×100% 3.总资产增长率=本年总资产增长额÷年初资产总额×100% 4.固定资产成新率=平均固定资产净值÷平均固定资产原值×100% 二、常用财务指标具体运用分析 1、变现能力比率 变现能力是企业产生现金的能力，它取决于可以在近期转变为现金的流动资产的多少。 （1）流动比率 公式：流动比率=流动资产合计/ 流动负债合计 意义：体现企业的偿还短期债务的能力。流动资产越多，短期债务越少，则流动比率越大，企业的短期偿债能力越强。

公司财务指标计算公式

（一）偿债能力指标 偿债能力是指企业清偿短期、长期债务的能力。 1、资产负债率 资产负债比率=负债总额 /资产总额 一般认为，该比率维护在40-60%之间较为合适，负债比率过高是不利的，应引起重视。 2、流动比率 流动比率=流动资产总额/流动负债总额 它反映企业短期负债的清偿能力，即每1元流动负债额中有多少流动资产额作保证。一般认为2:1的流动比率较好。若该比率过低，说明企业偿还能力较差，若该比率过高，说明企业的部分资金闲置。 3、速动比率 速动比率=流动资产总额-存货 /流动负债总额 因为存货不能马上形成支付能力，所以速动比率比流动比率更能准确反映企业的偿债能力。一般认为，该比率为1:1较好。 4、现金比率 反映企业即时偿还流动负债的能力，指标计算公式如下： 现金比率=（货币资金+三个月到期的短期投资和应收票据）/流动负债 现金比率越高，说明公司的短期偿债能力越强。 5、利息保障倍数 衡量企业偿还借款利息的能力，指标计算公式如下（如不能得到利息费用的详细资料，可用“财务费用”代替“利息费用”）： 利息保障倍数=（利润总额+利息费用）/利息费用 利息保障倍数指标反映出企业的经营所得保障支付负债利息的能力，它的倍数一般情况下应大于1，同时应选择5年中最低的比率作为最基本的偿付利息能力指标，否则就难以偿还债务及利息。但从短期看，由于折旧费、摊销费及折耗费等短期内不需要支付资金，所以利息保障倍数小于1时，企业通常也能偿还其利息债务。 6、应收账款损失率 应收账款损失率=坏账损失/应收账款总额 一般讲该指标越小越好，比率高应引起重视，必须到企业对应收帐款进行调查，找出原因。 7、经营活动产生的现金流量 反映企业以经营活动现金流入偿还债务的能力。（1）将销售商品、提供劳务收到的现金与购进商品、接受劳务付出的现金进行比较。在企业经营正常、购销平衡的情况下，二者比较的比率大，说明企业的销售利润大，销售回款良好，创现能力强。（2）将销售商品、提供劳务收到的现金与经营活动流入的现金总额进行比较，可大致说明企业产品销售现款占经营活动流入的现金的比重。比重大，说明企业主营业务突出，营销状况良好。（3）将本期经营活动现金净流量与上期进行比较，增长率越高，说明企业成长性越好。 （二）营运能力指标 1、应收账款周转率 反映了应收账款周转速度，及时收回应收账款，不仅能增强企业的短期偿债能力，也能反映出企业管理应收账款方面的效率。用时间表示的周转速度是应收账款周转天数，也叫平均应收账款回收期或平均收现期，其计算公式为： 应收账款周转率=销售收入÷平均应收账款

财务指标计算公式

一、新会计准则下财务指标的计算 1、流动比率＝流动资产/流动负债 流动资产取资产负债表中“流动资产合计”的期末余额 流动负债取资产负债表中“流动负债合计”的期末余额 2、速动比率＝（流动资产－存货）/流动负债 流动资产取资产负债表中“流动资产合计”的期末余额 存货取资产资产负债表中“存货”的期末余额 流动负债取资产负债表中“流动负债合计”的期末余额 3、存货周转率＝营业成本/平均存货 平均存货＝（存货年初数＋存货年末数）/2 营业成本取利润表中“营业成本”的本期金额 存货年初数取资产负债表中“存货”的年初余额 存货年末数取资产负债表中“存货”的期末余额 4、应收帐款周转率＝营业收入/平均应收账款 平均应收账款＝（应收账款年初数＋应收账款年末数）/2 营业收入取利润表中“营业收入”的本期金额 应收账款年初数取资产负债表中“应收账款”的年初余额 应收账款年末数取资产负债表中“应收账款”的期末余额

5、流动资产周转率＝营业收入/平均流动资产 平均流动资产＝（流动资产年初数＋流动资产年末数）/2 营业收入取利润表中“营业收入”的本期金额 流动资产年初数取资产负债表中“流动资产合计”的年初金额 流动资产年末数取资产负债表中“流动资产合计”的期末余额 6、经营活动现金流入量/销售收入＝经营活动现金流入量/营业收入 经营活动现金流入量取现金流量表中的“经营活动现金流入小计”的本期金额 营业收入取利润表中“营业收入”的本期金额 7、经营活动现金净流量与债务总额比＝经营活动现金净流量/负债总额 经营活动现金净流量取现金流量表中“经营活动产生的现金流量净额”的本期金额 负债总额取资产负债表中“负债合计”的期末余额 8、销售收入增长率＝本年营业收入增长额/上年营业收入 本年营业收入增长额＝本年营业收入－上年营业收入 本年营业收入取利润表中“营业收入”的本期金额 上年营业收入取利润表中“营业收入”的上期金额

主要财务指标计算公式

主要财务指标计算公式 （一）偿债能力指标偿债能力是指企业清偿短期、长期债务的能力。 1、资产负债率资产负债比率=负债总额/资产总额 分析提示：负债比率越大，企业面临的财务风险越大，获取利润的能力也越强。如果企业资金不足，依靠欠债维持，导致资产负债率特别高，偿债风险就应该特别注意了。资产负债率在55%—65%，比较合理、稳健;达到80%及以上时，应视为发出预警信号，企业应提起足够的注意。一般认为，该比率维护在40-60%之间较为合适，负债比率过高是不利的，应引起重视。 2、流动比率流动比率=流动资产总额/流动负债总额 意义：体现企业的偿还短期债务的能力。流动比率越高，说明企业短期偿债能力越强。国际上通常认为，流动比率的下限为100%，流动比率等于200%时较为适当。反映企业短期负债清偿能力，即每1元流动负债额中有多少流动资产额作保证。一般认为2:1的流动比率较好。若该比率过低，说明企业偿还能力较差，若该比率过高，说明企业的部分资金闲置。 3、速动比率速动比率=流动资产总额-存货/流动负债总额 意义：速动比率越高，表明企业偿还流动负债的能力越强。因为流动资产中，尚包括变现速度较慢且可能已贬值的存货，因此将流动资产扣除存货再与流动负债对比，以衡量企业的短期偿债能力。通常认为，速动比率等于100%时较为适当。 分析提示：低于1的速动比率通常被认为是短期偿债能力偏低。影响速动比率的可信性的重要因素是应收账款的变现能力，账面上的应收账款不一定都能变现，也不一定非常可靠。 因为存货不能马上形成支付能力，所以速动比率比流动比率更能准确反映企业的偿债能力。一般认为，该比率为1:1较好。 4、现金比率反映企业即时偿还流动负债的能力，指标计算公式如下： 现金比率=（货币资金+三个月到期的短期投资和应收票据）/流动负债 现金比率越高，说明公司的短期偿债能力越强。 5、利息保障倍数衡量企业偿还借款利息的能力，指标计算公式如下（如不能得到利息费用的详细资料，可用“财务费用”代替“利息费用”）： 利息保障倍数=（利润总额+利息费用）/利息费用 利息保障倍数指标反映出企业的经营所得保障支付负债利息的能力，它的倍数一般情况下应大于1，同时应选择5年中最低的比率作为最基本的偿付利息能力指标，否则就难以偿还债务及利息。但从短期看，由于折旧费、摊销费及折耗费等短期内不需要支付资金，所以利息保障倍数小于1时，企业通常也能偿还其利息债务。 6、应收账款损失率 应收账款损失率=坏账损失/应收账款总额 一般讲该指标越小越好，比率高应引起重视，必须到企业对应收帐款进行调查，找出原因。 7、经营活动产生的现金流量反映企业以经营活动现金流入偿还债务的能力。 （1）将销售商品、提供劳务收到的现金与购进商品、接受劳务付出的现金进行比较。在企业经营正常、购销平衡的情况下，二者比较的比率大，说明企业的销售利润大，销售回款良好，创现能力强。 （2）将销售商品、提供劳务收到的现金与经营活动流入的现金总额进行比较，可大致说明企业产品销售现款占经营活动流入的现金的比重。比重大，说明企业主营业务突出，营销状况良好。 （3）将本期经营活动现金净流量与上期进行比较，增长率越高，说明企业成长性越好。 （二）营运能力指标 1、应收账款周转率 反映了应收账款周转速度，及时收回应收账款，不仅能增强企业的短期偿债能力，也能反映出企业管理应收账款方面的效率。用时间表示的周转速度是应收账款周转天数，也叫平均应收账款回收期或平均收现期，其计算

财务指标计算公式

相关指标计算公式 （一）长短期偿债能力指标 1、资产负债率=负债总额/资产总额×100％ 2、利息保障倍数＝（利润总额＋利息费用）/利息费用 3、流动比例＝流动资产/流动负债×100％ 4、速动比例＝速动资产/流动负债×100％ 速动资产＝流动资产-存货-预付账款-待摊费用。 5、或有负债比率＝或有负债余额/所有者权益总额 或有负债余额＝已贴现商业承兑汇票金额＋对外担保金额＋未决诉讼、未决仲裁金额（除贴现与担保引起的诉讼或仲裁）＋其他或有负债金额（二）营运能力指标 6、应收账款周转率（次数）＝主营业务收入净额/应收账款平均余额 应收账款周转天数＝应收账款平均余额/（主营业务收入净额/计算期天数）＝计算期天数/应收账款周转率 计算期天数＝会计报表月份数×30天 7、存货周转率（次数）＝主营业务成本/存货平均余额 存货周转天数＝存货平均余额/（主营业务成本/计算期天数）＝计算期天数/存货周转率 （三）盈利能力指标 8、销售利润率（毛利率）＝销售利润/销售收入净额×100％ 销售利润=销售收入-销售成本-销售税金及附加。 9、总资产报酬率=（利润总额+利息费用）/平均资产总额X100% 平均资产=（资产总额年初数+资产总额年末数）/2。 10、净资产收益率=净利润/平均净资产×100% 平均净资产=（年初净资产+年末净资产）/2，该公式的分母是“平均净资产”（也可以使用“年末净资产”）。 （四）发展能力指标 11、销售收入增长率＝(本期销售收入－上期销售收入)/上期销售收入×100% 12、净利润增长率=(本期净利润额－上期净利润额)/上期净利润额×100%。 13、净资产增长率=(本期净资产总额－上期净资产总额)/ 上期净资产总额×100%。 另外： 盈利能力指标还有： 资产利润率＝利润总额/平均资产总额×100％ 发展能力指标还有： 1利润增长率＝（本年利润总额/上年利润总额－1）×100％ 2、总资产增长率＝（本年资产总额/上年资产总额－1）×100％ 3、资本积累率＝（本年所有者权益/上年所有者权益－1）×100％

财务指标测算公式及分析

财务指标测算及分析 1、变现能力比率 变现能力是企业产生现金的能力，它取决于可以在近期转变为现金的流动资产的多少。 （1）流动比率 公式：流动比率=流动资产合计/流动负债合计 企业设置的标准值：2 意义：体现企业的偿还短期债务的能力。流动资产越多，短期债务越少，则流动比率越大，企业的短期偿债能力越强。 分析提示：低于正常值，企业的短期偿债风险较大。一般情况下，营业周期、流动资产中的应收账款数额和存货的周转速度是影响流动比率的主要因素。 （2）速动比率 公式：速动比率=（流动资产合计-存货）/流动负债合计 保守速动比率=0.8（货币资金+短期投资+应收票据+应收账款净额）/流动负债 企业设置的标准值：1 意义：比流动比率更能体现企业的偿还短期债务的能力。因为流动资产中，尚包括变现速度较慢且可能已贬值的存货，因此将流动资产扣除存货再与流动负债对比，以衡量企业的短期偿债能力。

分析提示：低于1的速动比率通常被认为是短期偿债能力偏低。影响速动比率的可信性的重要因素是应收账款的变现能力，账面上的应收账款不一定都能变现，也不一定非常可靠。 变现能力分析总提示： （1）增加变现能力的因素：可以动用的银行贷款指标；准备很快变现的长期资产；偿债能力的声誉。 （2）减弱变现能力的因素：未作记录的或有负债；担保责任引起的或有负债。 2、资产管理比率 （1）存货周转率 公式：存货周转率=产品销售成本/[（期初存货+期末存货）/2] 企业设置的标准值：3 意义：存货的周转率是存货周转速度的主要指标。提高存货周转率，缩短营业周期，可以提高企业的变现能力。 分析提示：存货周转速度反映存货管理水平，存货周转率越高，存货的占用水平越低，流动性越强，存货转换为现金或应收账款的速度越快。它不仅影响企业的短期偿债能力，也是整个企业管理的重要内容。 （2）存货周转天数 公式：存货周转天数=360/存货周转率=[360*（期初存货+期末存货）/2]/产品销售成本 企业设置的标准值：120

主要财务指标计算公式

一、盈利能力分析 1.销售净利率=(净利润÷销售收入)×100%;该比率越大，企业的盈利能力越强。 2.资产净利率=(净利润÷总资产)×100%;该比率越大，企业的盈利能力越强。 3.权益净利率=(净利润÷股东权益)×100%;该比率越大，企业的盈利能力越强。 4.总资产报酬率=(利润总额+利息支出)/平均资产总额×100%;该比率越大，企业的盈利能力越强。 5.营业利润率=(营业利润÷营业收入)×100%;该比率越大，企业的盈利能力越强。 6.成本费用利润率=(利润总额÷成本费用总额)×100%;该比率越大，企业的经营效益越高。 二、盈利质量分析 1.资产现金回收率=(经营活动现金净流量÷平均资产总额)×100%;与行业平均水平相比进行分析。 2.盈利现金比率=(经营现金净流量÷净利润)×100%;该比率越大，企业盈利质量越强，其值一般应大于1。 3.销售收现比率=(销售商品或提供劳务收到的现金÷主营业务收入净额)×100%;数值越大表明销售 收现能力越强，销售质量越高。 三、偿债能力分析 1.净运营资本=流动资产-流动负债=长期资本-长期资产;对比企业连续多期的值，进行比较分析。 2.流动比率=流动资产÷流动负债;与行业平均水平相比进行分析。 3.速动比率=速动资产÷流动负债;与行业平均水平相比进行分析。 4.现金比率=(货币资金+交易性金融资产)÷流动负债;与行业平均水平相比进行分析。 5.现金流量比率=经营活动现金流量÷流动负债;与行业平均水平相比进行分析。 6.资产负债率=(总负债÷总资产)×100%;该比值越低，企业偿债越有保证，贷款越安全。 7.产权比率与权益乘数：产权比率=总负债÷股东权益，权益乘数=总资产÷股东权益;产权比率越低，企业偿债越有保证，贷款越安全。

各项财务指标计算公式

各项财务指标计算公式 1、资本利润率（净资产收益率）=净利润÷所有者权益平均余额×100% 所有者权益平均余额=（期初所有者权益余额+期末所有者权益余额）÷2 2、资产利润率（总资产报酬率）=利润总额÷资产总额平均余额×100% 资产平均余额=（期初资产总额+期末资产总额）÷2 3、收入利润率=营业利润÷营业收入×100% 4、支出利润率=营业利润÷营业支出×100% 5、成本收入比=业务及管理费÷营业收入×100% 6、利息回收率=本期实际收回利息÷ 本期应收回利息× 100% 7、负债成本率=（负债成本支出+筹资相关应摊费用）÷负 债平均余额×100% 8、不良贷款率=（次级类贷款+可疑类贷款+损失类贷款） ÷各项贷款×100% 9、资本充足率=（资本—扣除项）÷（风险加权资产+12.5 倍的市场风险资本）×100% 10、核心资本充足率=（核心资本—核心资本扣除项）÷（风 险加权资产+12.5倍的市场风险资本）×100%、拨备覆盖率=贷款损失准备÷（不良贷款余额）×100%

11、资产负债率=期末负债总额÷资产总额×100% 12、贷款损失准备充足率=贷款实际计提准备÷贷款应提准 备×100% 13、备付金比例=备付金÷各项存款×100% 14、流动性比例=流动性资产÷流动性负债×100% 15、存贷比=各项贷款÷各项存款×100% 备注：1—7项为盈利能力指标；8、9项为资产质量指标；10—15项为偿付能力指标。 16、经营利润=利润总额+贷款减值损失—应收利息（期末— 期初） 17、净资产比率=股东权益总额÷总资产（正常指示50%或更低） 18、固定资产净值率=固定资产净值÷固定资产原值（正常75%） 19、资本化比率=长期负债÷（长期负债+股东股益） 20%以下 20、速度比率=（流动资产-存货-预付费用-待摊费用）÷流动负债 备注：14少百分数、20反应的是安全性和偿债能力 17-19是反应财务结构是否合理的指标