CN104701842B - A kind of independent micro-grid electric power system and Reliability Estimation Method thereof - Google Patents

Abstract

The invention provides a kind of independent micro-grid electric power system and Reliability Estimation Method thereof.Independent micro-grid electric power system is divided into different feeder zone, the power-supply device operational factor of renewable energy power generation unit, non-renewable energy resources generating set and energy storage device and fault parameter in reading system, not only allow for the capacity unbalance impact on power supply reliability, also contemplate the impact on power supply reliability of equipment fault and grid structure, independent micro-grid electric power system power supply reliability can be assessed more accurately, various energy resources be can more effectively realize complementary, energy utilization rate and the power supply reliability of whole system improved.

Description

A kind of independent micro-grid electric power system and Reliability Estimation Method thereof

Technical field

The present invention relates to a kind of independent micro-grid electric power system and Reliability Estimation Method thereof, particularly relate to A kind of Reliability Estimation Method being applicable to balance based on trend.

Background technology

Along with the continuous growth of energy demand, greenhouse effect is further obvious, and utilize wind energy, solar energy etc. can Renewable source of energy generation technology rapidly becomes the current reply energy and the important means of environmental crisis.Independent micro-grid supplies Polytype distributed generation unit can be combined by electricity system, effectively realizes various energy resources complementary, Improve energy utilization rate and the power supply reliability of whole system.In remote and Island, independent micro-grid is powered System is one of effective means solving its powerup issue.

Regenerative resource often has randomness, intermittent feature.Set in the planning of independent micro-grid electric power system In meter, while making full use of regenerative resource, how to ensure that the power supply reliability of system is to need to pay close attention to One of key issue.Existing planing method is generally only capacity unbalance degree is referred to as the reliability of system Mark.For considering equipment fault impact further, need to add reliability assessment link in planning and designing, adopt The reliability level of system is evaluated with suitable reliability estimation method.

But, the reliability estimation method of current independent micro-grid electric power system is basic only around in autonomous system Generating-load capacity balance carries out reliability assessment, it is impossible to meet the planning and designing demand of independent micro-grid.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of Reliability Evaluation independent micro-grid more accurately and supplies Electricity system and Reliability Estimation Method thereof.

Along with the increase of independent micro-grid electric power system scale, it should also be taken into account that grid structure in reliability assessment Impact, in existing independent micro-grid electric power system Reliability Evaluation, do not consider that equipment fault brings Impact, owing to grid structure is complicated, load bus is more, middle pressure independent micro-grid electric power system is structurally Closer to the distribution system containing distributed power source.Currently exist some for the distribution containing distributed power source Systematic research, on the basis of considering system network shelf structure, analyzes distributed power source and connects with energy storage device Enter the impact on distribution Power System Reliability.But except for the difference that, the distribution system containing distributed power source is the most grid-connected Run, and independent micro-grid electric power system is in off-network state all the time, needs the power supply fully relying in microgrid Realize power balance.This feature determines the voltage problem of middle pressure independent micro-grid electric power system and compares distribution system The most prominent, due to higher resistive in distribution line, therefore voltage is simultaneously by active balance and reactive balance Double influence.And in this, existing method the most only considers intrasystem active balance, have ignored and be The interior reactive balance of system and the voltage problem brought thereof.

The technical solution used in the present invention is as follows:

A kind of independent micro-grid electric power system, it is characterised in that: independent micro-grid electric power system is divided into different Feeder zone；Master control power supply uses concentrates access way, is connected from different feeder zone through transformator；Also Including renewable energy power generation unit and or energy storage device, be arranged on high voltage side of transformer be connected bus on or It is arranged on inside feeder zone.

Also include automatic safety device, be arranged on high voltage side of transformer and feeder zone entrance, when fault Automatically cut off the connection of fault zone and other region of electric power system.

Also include Manual isolation switch, be arranged in the branch of electric power system grid structure, for respective negative The excision operation of lotus point.

A kind of Reliability Estimation Method based on above-mentioned independent micro-grid electric power system, including capacity unbalance Reliability Evaluation, it is characterised in that: also include equipment fault Reliability Evaluation；Concrete grammar walks Suddenly it is:

One, independent micro-grid electric power system is divided into different feeder zone, regenerative resource in reading system The power-supply device operational factor of generating set, non-renewable energy resources generating set and energy storage device and fault ginseng Number, and the basic Power Flow Information of feeder zone and fault message；

Two, according to all power-supply devices and the fault parameter of feeder zone, to described power-supply device and feeder line district Territory carries out moment state sampling, obtains the state change cyclic sequence of described power-supply device and feeder zone；

Three, described state change cyclic sequence is combined with the topological structure of system, obtain system each imitative Normal connected region under true step-length；

Four, according to the schedulable power type in the normal connected region of described system, coordinated operation strategy is selected The preliminary active balance judging system, and record the unlatching number of units of non-renewable energy resources generating set, energy storage dress The charge-discharge electric power put and the active power dispatch information of the excess power of renewable energy power generation unit；

Five, according to described active power dispatch information, Load flow calculation is utilized to obtain active power vacancy and the nothing of system Merit power shortage；

Six, according to described system active power vacancy and reactive power vacancy, to non-renewable energy resources electromotor The dispatch command of group and energy-storage battery is modified, and calls the load reduction table of interruptible load, is Whole load point power-off conditions under each simulation step length in system；

Seven, according to described load point power-off condition under each simulation step length, each load point is added up in each week Power failure frequency, power off time and power failure amount in phase, and according to described load point region, add up each feedback Power off time within each cycle of line region and whole system and power failure amount, and then obtain load point, feeder line Region and three grades of reliability indexs of system.

In described step 2, sequential Monte Carlo simulation method is utilized to carry out described moment state sampling.

In described step 7, according to each load point power down mode under each simulation step length and power failure amount, system Count each load point power failure frequency within each cycle, power off time and power failure amount to refer to as load point reliability Mark.

In described step 7, according to power down mode, power failure amount and the affiliated feeder zone thereof of described load point, Obtain each feeder zone power down mode under each simulation step length and power failure amount, and add up each feeder zone often Average power off time in the individual cycle and average power failure amount are as feeder zone reliability index.

In described step 7, according to power down mode, the power failure amount of described feeder zone, obtain described system and exist Power down mode under each simulation step length and power failure amount, and add up the average power failure within each cycle of the described system Time and average power failure amount are as Reliability Index.

The described cycle is 1 year, and described simulation step length is 1 hour.

One compared with prior art, the invention has the beneficial effects as follows: not only allows for capacity unbalance to power supply The impact of reliability, it is also contemplated that equipment fault and the grid structure impact on power supply reliability, it is possible to more smart True assessment independent micro-grid electric power system power supply reliability, can more effectively realize various energy resources complementary, improve whole The energy utilization rate of individual system and power supply reliability.

Accompanying drawing explanation

Fig. 1 is the system structure schematic diagram of a present invention wherein embodiment.

Fig. 2 is the schematic flow sheet of a Reliability Estimation Method of the present invention wherein embodiment.

Fig. 3 is the hard charging strategy schematic flow sheet of a present invention wherein embodiment.

Fig. 4 be a present invention wherein embodiment accomplish strategic process schematic diagram.

Detailed description of the invention

In order to make the purpose of the present invention, technical scheme and advantage clearer, below in conjunction with accompanying drawing and reality Execute example, the present invention is further elaborated.Only should be appreciated that specific embodiment described herein In order to explain the present invention, it is not intended to limit the present invention.

Any feature disclosed in this specification (including any accessory claim, summary and accompanying drawing), removes Non-specifically describes, all can be by other equivalences or have the alternative features of similar purpose and replaced.That is, remove Non-specifically describes, and each feature is an example in a series of equivalence or similar characteristics.

As it is shown in figure 1, a kind of independent micro-grid electric power system, independent micro-grid electric power system is divided into different Feeder zone；In this specific embodiment, renewable energy power generation machine is wind-driven generator, non-renewable energy resources Electromotor is diesel-driven generator；Diesel-driven generator as system master power supply uses concentration access way, warp Transformator is connected from different feeder zone；Wind-driven generator WT and energy storage device EA is (concrete real at this Execute in example as batteries to store energy device) it is arranged on the bus that high voltage side of transformer is connected or is arranged on feeder line district Territory is internal (being arranged on inside feeder zone in this specific embodiment).

In this specific embodiment, it is contemplated that the line fault in transformer fault and feeder zone, transformator High-pressure side and porch, feeder zone are respectively arranged with automatic safety device.When an error occurs, automatic safety device Intrasystem irregular operating state can be detected in time, by trip operation rapid disengagement failure region be Unite the connection in other region, thus realize the isolation of fault zone.

In this specific embodiment, it is inside each feeder zone at tree network, root node and area entry Automatic safety device is connected, and load point is dispersed in the Heavenly Stems and Earthly Branches and the branch of network.Some branch of tree network It is provided with Manual isolation switch, it would be preferable to support the excision operation of corresponding load point, but does not contains inside each feeder line district Automatic safety device.

As in figure 2 it is shown, Reliability Estimation Method based on above-mentioned independent micro-grid electric power system, including holding The uneven Reliability Evaluation of amount, also includes equipment fault Reliability Evaluation；At this specific embodiment In, with 1 year as cycle, within 1 hour, carrying out reliability assessment for step-length, concrete grammar step is:

One, independent micro-grid electric power system is divided into different feeder zone, regenerative resource in reading system The power-supply device operational factors such as generating set, non-renewable energy resources generating set and energy storage device and fault ginseng Number, and the basic Power Flow Information of feeder zone and fault message；

In the system shown in figure 1, high voltage side of transformer and porch, each feeder zone are equipped with and automatically protect dress Put.Under this structure, all elements in feeder zone are all at the protection domain of its porch automatic safety device In, when any element failure in region, rapid action is made whole feeder line by corresponding automatic safety device Zone isolation, thus all loads in causing this region have a power failure.When certain region is isolated, in this region The power supply of all renewable energy power generation equipment and energy storage device is all by cut-out.In sum, in system arbitrarily The fault of circuit all can be equivalent to the fault in respective feed connection region, thus can be using feeder zone as an entirety It is modeled, effectively to reduce the time of fault sampling.With the independent micro-grid electric power system shown in Fig. 1 it is Example, whole system can be divided into 4 regions according to the position of automatic safety device.Region 0 is diesel-driven generator With the master control power supply area of transformator composition, region 1～3 is different load area.

Two, according to all power-supply devices and the fault parameter of feeder zone, to described power-supply device and feeder line district Territory carries out moment state sampling, obtains the state change cyclic sequence of described power-supply device and feeder zone；

In this specific embodiment, based on sequential Monte Carlo simulation method, element each in system is carried out state Sampling, produces the running status sequence of each element.

Three, described state change cyclic sequence is combined with the topological structure of system, obtain system each imitative Normal connected region under true step-length；

In sampling generation system after the running status sequence of each power supply and feeder zone, it becomes possible to according to system Topological structure obtains the system connected region in each moment and (is not i.e. automatically protected the district of device isolation Territory).As a example by Fig. 1 system, when in system, fault-free occurs, connected region is that whole middle pressure is independent micro- Net electric power system.When fault occurs in region 0 (transformer fault), all diesel-driven generators all move back Going out to run, connected region is region 1,2,3, and energy storage device is by the master control power supply temporarily as system.When When fault occurs in zone 1, separation generator and energy storage device are the most out of service, and connected region is region 0、2、3.When fault occurs in region 2 (or region 3), connected region be 0,1,3 (or 0,1, 2), diesel-driven generator will cooperate with wind-driven generator, energy storage device, to fault-free block supply.

Four, according to the schedulable power type in the normal connected region of described system, coordinated operation strategy is selected The preliminary active balance judging system, and record the unlatching number of units of non-renewable energy resources generating set, battery The active power dispatch information of the excess power of charge-discharge electric power and renewable energy power generation unit；

The Real-time Power Flow poised state of system is judged based on system running policy.This specific embodiment is based on having On the coordinated operation policy grounds of merit balance, it is further proposed that correction strategy based on trend balance is in terms of simultaneously And active balance and the reactive balance impact on system reliability.

In the independent micro-grid electric power system being originally embodied as exist two kinds of schedulable power supplys: diesel-driven generator and Batteries to store energy device.According to the selection of schedulable power supply, the coordinated operation strategy of independent micro-grid electric power system Three classes can be divided into: energy storage scheduling strategy, diesel-driven generator scheduling strategy, the association of energy storage and diesel-driven generator Adjust scheduling strategy.In view of power failure and the impact of area fault, this specific embodiment is in coordinated operation plan Count above-mentioned three class situations in slightly simultaneously:

Floating charge strategy: if diesel-driven generator region is isolated by protection device action, system will be with accumulator Energy storage is as master control power supply, and coordinates wind-driven generator to exert oneself to meet workload demand.Floating charge strategy is used to make For the operation reserve under energy storage scheduling method, its dispatching principle is: if regenerative resource is exerted oneself and is higher than in system Workload demand, dump power is energy storage charging, when energy storage maximum charge power can not dissolve dump power, Surplus power is recorded as regenerative resource and abandons power EP (t)；Otherwise, if regenerative resource is exerted oneself low in system In workload demand, insufficient section is supplemented by energy storage electric discharge.

Strategy without energy storage: if batteries to store energy region is isolated by protection device action, system runs on bavin Under oily hair motor scheduling strategy.The diesel-driven generator scheduling strategy used is: preferentially utilize development of renewable energy Electricity is powered to load, and insufficient section is provided by diesel-driven generator.Under this strategy, clean according to this step-length of system Load condition selects diesel-driven generator to open number of units: if net load is less than 0, one diesel generation of enforced opening Machine ensures system stable operation, and records regenerative resource and abandon power EP (t)；If net load is more than 0, root Suitable diesel-driven generator is selected to open number of units according to net load value size, if available diesel-driven generator all puts into Run and still can not meet net load demand, make diesel-driven generator open number of units and send out number of units equal to available bavin.

Hard charging strategy: when in independent micro-grid all the most normally devote oneself to work containing power supply area time, system is in fortune Need during row to coordinate the relation between diesel-driven generator, renewable energy power generation and energy storage.In order to as far as possible Reduce the fuel consumption of diesel-driven generator, more fully utilize intrasystem regenerative resource, select firmly to fill Electricity strategy is as the coordinated operation strategy under this pattern.Under this strategy, diesel-driven generator and batteries to store energy can Alternate play main power source meets net load demand (system total load and the difference of generated output of renewable energy source), its Flow process is as shown in Figure 3.

In Fig. 3, P1-P6 represents system net load respectively, counts the net load of system reserve capacity, electric power storage Pond maximum charge power, accumulator maximum discharge power, diesel generating set EIAJ, diesel-driven generator Group minimum load (more than 0).This strategy is according to the system net load in this step-length and spare capacity, Yi Jishang Diesel-driven generator in one step-length is opened number of units and is calculated with energy storage charge-discharge electric power and should open bavin in this step-length and send out Number of units n_t, and then according to system net carry calculation accumulator cell charging and discharging power P_batT (), system abandon ENERGY E P (t) Etc. index, the correction strategy link for next step provides essential information.It should be noted that in coordinated operation Strategy do not calculates the scarce delivery of system, but consider in follow-up correction strategy system generating capacity with Equilibrium relation between workload demand.

Five, according to described merit schedule information, Load flow calculation is utilized to obtain the active power vacancy of system and idle Power shortage；

Six, according to described system active power vacancy and reactive power vacancy, utilize correction strategy to can not be again The dispatch command of raw energy generator group and energy-storage battery is modified, and calls the reduction plan of interruptible load Slightly, whole load point power-off conditions under each simulation step length in system are obtained；

On above-mentioned coordinated operation policy grounds based on active balance, present invention further proposes based on tide The correction strategy of mobile equilibrium.Correction strategy flow process is as shown in Figure 4:

For calculating system load flow, needing the given node of system, branch road and electromotor information, the present invention selects Above-mentioned information is stored, in order to trend input information is recombinated with feeder zone for ultimate unit.Need It is emphasized that two way convertor in energy-storage system of accumulator can run at four quadrants, i.e. it can be In Converter Capacity limits, absorb according to system requirements or release active power and reactive power.Therefore for The independent micro-grid electric power system that reactive capability is limited, must count and the nothing of batteries to store energy in its operation reserve Function power.In addition, it is contemplated that the node voltage brought when renewable energy power generation power is higher than workload demand is lifted The problem of liter, abandons power in the reduction that meter of the present invention and regenerative resource are exerted oneself, i.e. coordinated operation Policy Result EP (t) counts in Load flow calculation not as the effective output of wind-driven generator.

In correction strategy, gain merit real-time with system of the instruction that each power supply is issued by independent micro-grid electric power system Vacancy P_lack(t) and no-power vacancy Q_lackT () is relevant, its calculation is as follows:

P_lack(t)=max (0, P_s.re(t)-P_s.max(t)) (1)

Q_lack(t)=max (0, Q_s.re(t)-Q_s.max(t)) (2)

In formula, P_s.re(t)、Q_s.reT () meritorious, idle is exerted oneself for balance in power flow solutions that node should provide； P_s.max(t)、Q_s.maxT () is that the maximum that can be provided by of main power source is meritorious, reactive power, when diesel-driven generator or storage When energy system is as main power source, it calculates as follows:

$\left\{\begin{array}{c}{P}_{s.\max }\left(t\right)=P_{dg.\max }\left(t\right)=n_t{S}_{dg}\\ Q_{s.\max }\left(t\right)=Q_{dg.\max }\left(t\right)=\sqrt{{\left(n_t{S}_{dg}\right)}^2-{\left(n_t{P}_{dg}\right(t\left)\right)}^2}\end{array}\right.---\left(3\right)$

$\left\{\begin{array}{c}{P}_{s.max}\left(t\right)=P_{bat.max}\left(t\right)=P_{dis.max}\left(t\right)\\ Q_{s.max}\left(t\right)=Q_{bat.max}\left(t\right)=\sqrt{S_{con}^2-P_{bat}^2\left(t\right)}\end{array}\right.---\left(4\right)$

In formula, P_dis.maxT () is the maximum discharge power of energy-storage system；S_dgFor diesel oil Rated motor capacity；S_con For energy storage two way convertor rated capacity；P_bat(t) and P_dgT () is respectively energy storage device, diesel-driven generator is gained merit Exerting oneself, their initial value is given by coordinated operation strategy, and constantly updates in correction strategy.

With meritorious vacancy P_lack(t), no-power vacancy Q_lackT () is foundation, the correction strategy principle that the present invention proposes As follows: when energy-storage system is as main power source, if there is power shortage, open the diesel oil of an armed state Electromotor makes up this vacancy；When diesel-driven generator is as main power source, if there is power shortage, preferentially adjust This vacancy is made up with meritorious, the reactive energy of energy-storage system, when energy-storage system is sufficient to compensate for vacancy, Reselection is opened the diesel-driven generator of an armed state and is made up this vacancy；If all power supplys are the most in system It is in full hair-like state, but still suffers from power shortage, now need to call load and cut down strategy.

Described load cuts down strategy: determine the interruptible load in independent micro-grid electric power system, and according to having Workload amount from small to large and or is cut down according to significance level sequential build load from lightweight to heavyweight Table.

Described load is cut down strategy and is also included, when carrying out load and cutting down, with described load reduction table for depending on According to, the most meritorious and load or burden without work of excision interruptible load point, to currently after excision each time Whether meritorious total load and the idle total load of system are updated, rejudge master control source nominal capacity and can Meet the system total load after updating, then can cut down termination, system resumes power by load, record and can interrupt The excision total amount of load, otherwise continue executing with load cut down strategy, until meet described judgement or all can in Till disconnected load is the most cut.

Described load is cut down strategy and is also included, if still can not meet described judgement after excising all interruptible loads Foundation, in system, all load point all have a power failure.

In view of the impact of grid structure, all in each feeder zone it is connected with main line through Manual isolation switch Load point is regarded as interruptible load, can be cut when generation capacity deficiency in load cuts down strategy Remove.Under trend equilibrium condition, the meritorious of interruptible load point and reactive power should be paid close attention to simultaneously.This is concrete Embodiment only considers single load type, and such as all load is resident load, and therefore load is cut down suitable Sequence is only relevant with loading.For improving analog rate, heuristic load is taked to cut down strategy herein: first false Fixed all load point are not cut down, and call coordinated operation strategy and correction strategy and carry out the operation shape of analog systems State.When there is the situation of system generation capacity deficiency, the interruptible load of load total amount minimum is preferentially cut Removing, repeating this process until meeting following formula:

$P_{s.re}^2\left(t\right)+Q_{s.re}^2\left(t\right)\≤S_{mp}^2\left(t\right)---\left(5\right)$

In formula, S_mpT () is the rated capacity of current system main power source.If this formula meets, show that system can be passed through Load is cut down strategy and is restored electricity, and now system blackout time LT (t) is recorded as 0, power failure amount UL (t) record Total amount L is cut down for interruptible load_cut(t)。

It should be noted that due to interruptible load Limited Number in system, take load to cut down strategy not Necessarily it is able to ensure that system reaches power balance.If interruptible load is still unsatisfactory for formula (5) after all cutting down Requirement, whole system will have a power failure less than workload demand completely because of generating capacity.The now system blackout time LT (t) is recorded as 1 hour, and power failure amount UL (t) is recorded as Real-time Load L (t) of whole system.

Seven, according to described load point power-off condition under each simulation step length, each load point is added up in each week Power failure frequency, power off time and power failure amount in phase, and according to described load point region, add up each feedback Power off time within each cycle of line region and whole system and power failure amount, and then obtain load point, feeder line Region and three grades of reliability indexs of system.

Obtain each load point within a cycle after the power-off condition of each step-length, respective feed connection region real-time State is just determined.Cut down the effect of strategy in view of load, judge in each step-length according to following method The state of feeder zone: to any feeder zone, if the power supply of the most all load point is all interrupted, this feeder line Region is in malfunction, and power off time is recorded as a step-length, and it is total that power failure amount is recorded as region internal loading Amount；If wherein only having the power failure of interruptible load point, this feeder zone is in risk status, does not remember and stops The electricity time, power failure amount is recorded as interruptible load and cuts down total amount；If all load point normal power supply, this feeder lines It is all 0 that region is in normal condition, power off time and power failure amount.

Real-time status based on feeder zone, the real-time status of system can also determine uniquely: if in system All load area runs on normal condition, then system also runs on normal condition；If having any negative in system Lotus region is in malfunction, then system is also at malfunction.On this basis, carried reliability assessment Method can not only obtain power off time and power failure frequency, the power off time phase of each load area of each load point Hope (LOLE), expected energy not supplied (LOEE) index, additionally it is possible to obtain whole system LOLE, The indexs such as LOEE, System average interruption frequency (SAIFI), average power off time (SAIDI):

${\mathrm{UL}}_i\left(t\right)=\underset{j\∈Z_i}{\Σ}{E}_j\left(t\right)---\left(7\right)$

${\mathrm{LOLE}}_i=\frac{8760}{T}\underset{t=1}{\overset{T}{\Σ}}{\mathrm{LT}}_i\left(t\right)---\left(8\right)$

${\mathrm{LOEE}}_i=\frac{8760}{T}\underset{t=1}{\overset{T}{\Σ}}{\mathrm{UL}}_i\left(t\right)---\left(9\right)$

LT_sys(t)=max (LT_i(t)) (10)

${\mathrm{UL}}_{sys}\left(t\right)=\underset{i}{\Σ}{\mathrm{UL}}_i\left(t\right)---\left(11\right)$

${\mathrm{LOLE}}_{sys}=\frac{8760}{T}\underset{t=1}{\overset{T}{\Σ}}{\mathrm{LT}}_{sys}\left(t\right)---\left(12\right)$

${\mathrm{LOEE}}_{sys}=\frac{8760}{T}\underset{t=1}{\overset{T}{\Σ}}{\mathrm{UL}}_{sys}\left(t\right)---\left(13\right)$

$SAIFI=\frac{\underset{j\∈S}{\Σ}{\mathrm{\λ}}_j{N}_j}{N_j}---\left(14\right)$

$SAIDI=\frac{\underset{j\∈S}{\Σ}{U}_j{N}_j}{N_j}---\left(15\right)$

In formula, subscript i is expressed as the correlative of feeder zone i；Subscript sys is expressed as the correlative of system； LT (t), UL (t) represent power off time and power failure amount in t step-length respectively；U_j(t)、E_jT () represents t step-length respectively in The power off time of load point j and power failure amount；λ_j、U_jAnd N_jRepresent the power failure frequency that load point j is annual respectively Rate, power off time and number of users；T represents the periodicity (i.e. year number) that reliability assessment experiences；Z_iRepresent Load point set in the i of feeder zone；S represents the load point set in whole system.

In the present invention, the capacity unbalance impact on power supply reliability is not only allowed for, it is also contemplated that equipment fault With the grid structure impact on power supply reliability, it is possible to power can for assessment independent micro-grid electric power system more accurately By property, can more effectively realize various energy resources complementary, the energy utilization rate and the power supply that improve whole system are reliable Property.

Claims (8)

1. a reliability estimation method for the power supply of independent micro-grid electric power system,

In independent micro-grid electric power system, independent micro-grid electric power system is divided into different feeder zone；Master control power supply uses concentrates access way, is connected from different feeder zone through transformator；Also include renewable energy power generation unit and energy storage device, be arranged on the bus that high voltage side of transformer is connected or be arranged on inside feeder zone；

In concrete appraisal procedure, including capacity unbalance Reliability Evaluation, also include equipment fault Reliability Evaluation；Concrete grammar step is:

One, independent micro-grid electric power system is divided into different feeder zone, the power-supply device operational factor of renewable energy power generation unit, non-renewable energy resources generating set and energy storage device and fault parameter in reading system, and the basic Power Flow Information of feeder zone and fault message；

Two, according to all power-supply devices and the fault parameter of feeder zone, described power-supply device and feeder zone are carried out moment state sampling, obtain the state change cyclic sequence of described power-supply device and feeder zone；

Three, described state change cyclic sequence is combined with the topological structure of system, obtain the system normal connected region under each simulation step length；

Four, according to the schedulable power type in the normal connected region of described system, select coordinated operation strategy tentatively to judge the active balance of system, and record the active power dispatch information of the excess power of the unlatching number of units of non-renewable energy resources generating set, the charge-discharge electric power of energy storage device and renewable energy power generation unit；

Five, according to described active power dispatch information, Load flow calculation is utilized to obtain active power vacancy and the reactive power vacancy of system；

Six, according to described system active power vacancy and reactive power vacancy, the dispatch command of non-renewable energy resources generating set and energy storage device is modified, and call the load reduction table of interruptible load, obtain whole load point power-off conditions under each simulation step length in system；

Seven, according to described load point power-off condition under each simulation step length, add up each load point power failure frequency within each cycle, power off time and power failure amount, and according to described load point region, add up each feeder zone and the whole system power off time within each cycle and power failure amount, and then obtain load point, feeder zone and three grades of reliability indexs of system.

Reliability Estimation Method the most according to claim 1, in described step 2, utilizes sequential Monte Carlo simulation method to carry out described moment state sampling.

Reliability Estimation Method the most according to claim 1 and 2, in described step 7, according to each load point power down mode under each simulation step length and power failure amount, add up each load point power failure frequency within each cycle, power off time and power failure amount as load point reliability index.

Reliability Estimation Method the most according to claim 1, in described step 7, power down mode, power failure amount and affiliated feeder zone thereof according to described load point, obtain each feeder zone power down mode under each simulation step length and power failure amount, and add up each feeder zone average power off time within each cycle and average power failure amount as feeder zone reliability index.

Reliability Estimation Method the most according to claim 1, in described step 7, power down mode according to described feeder zone, power failure amount, obtain described system power down mode under each simulation step length and power failure amount, and add up the described system average power off time within each cycle and average power failure amount as Reliability Index.

Reliability Estimation Method the most according to claim 1, the described cycle is 1 year, and described simulation step length is 1 hour.

Reliability Estimation Method the most according to claim 1, described electric power system also includes automatic safety device, is arranged on high voltage side of transformer and feeder zone entrance, automatically cuts off the connection of fault zone and other region of electric power system when fault.

8. according to the Reliability Estimation Method described in claim 1 or 7, described electric power system also includes Manual isolation switch, is arranged in the branch of electric power system grid structure, for operating the excision of corresponding load point.