CN102969721A - Parallel perceptual reactive compensation method for inhibiting steady over-voltages of power distribution networks containing small hydropower - Google Patents
Parallel perceptual reactive compensation method for inhibiting steady over-voltages of power distribution networks containing small hydropower Download PDFInfo
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Abstract
The invention relates to a parallel perceptual reactive compensation method for inhibiting steady over-voltages of power distribution networks containing small hydropower. The method comprises S1, selecting volumes of perceptual reactive compensation reactors: adopting 30% to 40% of rated capacities of small hydropower generators; S2, connecting and installing parallel perceptual reactive compensation reactors on low-voltage sides of boosting transformers of small hydropower stations; S3, determining grouping situations of low-voltage parallel reactors according to the volumes of the reactors, wherein, the reactors of 150 kvar and below 150 kvar are recommended to be not grouped, the reactors in a range of 150 kvar to 300 kvar are divided into two groups, and the reactors of more than 300 kvar are divided into three groups; and S4, using low-voltage levels consistent with low-voltage side levels of the boosting transformers in the small hydropower stations. According to the parallel perceptual reactive compensation method for inhibiting steady over-voltages of power distribution networks containing small hydropower, the parallel reactors are configured on low-voltage sides of the boosting transformers of the small hydropower stations, the control capacity to line voltages is enhanced apparently, and good practicability and operability are provided.
Description
Technical field
The present invention relates to a kind of method that suppresses the power distribution network steady-state overvoltage, especially relate to and a kind ofly adopt inductive reactive power compensation reactor in parallel effectively to solve small power supply to cause the high method of distribution network voltage.
Background technology
In the area of hydroelectric resources than horn of plenty, the Devoting Major Efforts To Developing of small power station has effectively been alleviated the phenomenon of rural power grids power supply shortages, but because small power station is distributed in mostly from the mountain area of load center away from, transmission distance is far away and wire diameter is little, and small power station mostly is radial-flow type, lack regulating power, power distribution network is meritorious, reactive power distribution is obvious seasonal variety, causes the system voltage fluctuation serious.Water power is sent out greatly season 10kV distribution line terminal voltage and is reached 12kV even higher, not only user's side electric equipment is worked the mischief, and also causes the safety that the small hydropower station set end voltage is high, jeopardize generating set, has also had a strong impact on the safety and economic operation of power distribution network.The distribution circuit electric voltage that contains small power station often surmounts the upper limit and forms steady-state overvoltage, has become in recent years the most problem of headache of China's distribution network voltage reactive management aspect, and is in the urgent need to address.
A kind of reactive power compensation collocation method that comparatively approaches with the application is exactly low pressure centralized compensation mode, namely carry out centralized compensation in distribution transformer 380V side, usually adopt micro-processor controlled low voltage parallel capacitor cabinet, capacity kilovar does not wait to hundreds of tens, drops into the capacitor of respective numbers according to the fluctuation of customer charge level and follows the tracks of compensation.Main purpose is to improve the special-purpose user's of change power factor, realizes idle in-situ balancing, and the damage of falling that power distribution network and distribution are become has certain effect, also helps to guarantee this user's voltage levvl.
But above-mentioned Reactive Compensation Mode mainly is to adopt shunt capacitor to compensate the reactive requirement of low-voltage customer and the reactive loss of distribution line and transformer, is intended to improve load line voltage distribution problem on the low side when heavier.But cause the distribution line terminal voltage to get over the situation of the steady-state overvoltage of the upper limit for containing small power station, the capacitive compensation device is helpless.The present invention emphasizes is to adopt inductive reactive power compensation (low pressure shunt reactor) to offset or suppress to send because of small power station the problem of the power distribution network steady-state overvoltage that power causes, and selects by way of compensation point of small hydropower station side.
Except the installation reactive power compensator improves quality of voltage and reduces the wastage, can also be by changing distribution line lead (increase wire diameter) and adjusting two kinds of methods of small power station's Generation in Leading Phase Operation.But from actual, replacing distribution line quantities is large, cost is higher, and consider that steady-state overvoltage is owing to small power station's access causes, so at first should consider to bear corresponding responsibility by small power station, so the method for restringing should still just be considered to adopt after inductive reactive power compensation is done by small power station whenever necessary.On the other hand, be limited to appointed condition and Personnel Skill Levels, small power station's machine leading phase operation difficulty is very large, is used hardly in actual conditions.
Summary of the invention
Technical problem to be solved by this invention, just provide a kind of method that adopts inductive reactive power compensation reactor in parallel to reduce distribution network voltage, its quantities is little, cost is lower, easy to implement, can effectively solve small power supply and cause the regular too high problem of distribution network voltage.
Solve the problems of the technologies described above, the technical solution used in the present invention is as follows:
A kind of inductive reactive power compensation in parallel suppresses to contain the method for small power station's power distribution network steady-state overvoltage, may further comprise the steps:
The selection of S1 inductive reactive power compensation reactor capacity: get 30% ~ 40% of small power station's generator rated capacity;
Give and power factor is that the reactive power that sent in 0.90 ~ 0.95 o'clock is all sponged by reactor by expiring of small power station's rated output, 0.90 the time Q/P=0.4359, and 0.95 o'clock Q/P=0.3123, for this reason, the compensation total capacity of reactor can be taken as 30% ~ 40% of generator rated capacity and require configuration.If small power station is with power factor 1.0 operation, then after small hydropower station disposes the low pressure shunt reactor of this value range, the power factor of step-up transformer still is unlikely to affect small power station and carries specified active power about leading about 0.95; In addition, the reactor capacity is crossed the ability to bear that senior general surpasses the small hydropower station owner, and the too small steady-state overvoltage scarce capacity that then suppresses is so recommend the compensation total capacity to be taken as 30% ~ 40% of generator rated capacity.
The selection of S2 shunt reactor compensated position: install in the access of small hydropower station step-up transformer low voltage side;
Installation site (electric pressure) difference of shunt reactor in the small hydropower station, the effect of bringing be difference to some extent also.Suppose that the step-up transformer no-load voltage ratio in the small hydropower station is 0.38/11.When small power station sends on a small quantity when idle, this moment, the direction of P and Q was consistent; By the π type equivalent circuit of transformer as can be known, if when shunt reactor was installed the 10kV side, the power that small power station sends flow through equiva lent impedance 1/kZ
TCan produce a pressure drop Δ V
1And when shunt reactor is installed in the 380V side of the change of boosting, flow through 1/kZ
TPower then can reduce the pressure drop Δ V that causes
2Inevitable less than Δ V
1, so distribution line terminal voltage value is low when being bound to be contained in the high-pressure side than reactor; When small power station's leading phase operation, P and Q opposite direction when reactor is installed in the 380V side, flow through 1/kZ
TReactive power many must be installed in the 10kV side than reactor the time, by dV=(PR-QX)/V as can be known, Q is larger, then dV is less, corresponding distribution line terminal voltage is also just lower; As seen, see technically that inductive reactive power compensation adopts low pressure grade better effects if, and equipment investment is lower.Select small hydropower station to also have two aspects as the reason of inductive reactive power compensation point: one is that small hydropower station has the on duty and equipment of people to enclose the theftproof performance height; Since the two is the steady-state overvoltage of power distribution network is that the small hydropower station access causes, just should require it to bear corresponding responsibility.
It is fixed that the grouping situation of S3 low pressure shunt reactor is come according to the reactor amount of capacity;
Recommend 150kvar and following reactor not to divide into groups, 150 ~ 300kvar divides two groups, and what 300kvar was above divides three groups, selects input group number according to local voltage levvl, makes every effort to drop into enough reactors and avoids voltage to surpass 1.1 times of load voltage values.
Determining of S4 inductive reactive power compensation reactor voltage grade: adopt the low pressure grade consistent with step-up transformer low voltage side grade in the small hydropower station, such as 0.38kV.
The principle of the invention:
Small power station's access causes the out-of-limit Analysis on Mechanism of distribution circuit electric voltage;
For electric network element, its voltage loss is Δ V=(PR+QX)/V, when the distribution line end exists power supply and generate output above the workload demand on the distribution line, flowing backwards will appear in active-power P and reactive power Q on the circuit, then by following formula as can be known line end will than transformer station end exceed one on the occasion of voltage difference delta V, in the certain situation of substation bus bar voltage V, P or Q are larger, and Δ V is larger.In general, distribution line terminal wire diameter in mountain area is all smaller, so R is larger, and circuit is longer, and R is also larger.Therefore the generating of small power station's distributed more, send that power is larger, circuit is longer, wire is thinner, Δ V is just larger, terminal voltage is just higher.The access of Here it is small power station causes under some operational mode distribution network voltage to get over the essential reason of the upper limit.
The checking of above-mentioned principle:
End is with the modeling and simulation of the out-of-limit situation of distribution circuit electric voltage of small power station.
Set up an end with the distribution line model of small power station, establishing wire type is LGJ-95, every section long 9km of circuit.The varying capacity 1000kVA that boosts of small power station, the burden with power that no-load voltage ratio is 0.38/10,1,2, No. 3 node is respectively 50kW, 30kW and 20kW; Meritorious the exerting oneself of line end small power station is set to 800kW, and idle exerting oneself is made as 200kvar.By being calculated, the trend of this typical case's underloading power distribution network can verify above-mentioned mechanism.
Generally speaking, under the heavier large mode of load, small power station generally is required the power factor generating at 0.85-0.90; And in little mode, then require 0.90-0.95 even reach 1.0 to generate electricity.Large mode namely 1 year internal loading relatively heavier period, the whole network voltage compared with normal level is on the low side; Little mode is namely loaded relatively light, and the whole network voltage compared with normal level is higher.One of perception compensation comparatively rational target for this reason, therefore small power station also sends the idle burden that increases the weight of power distribution network when avoiding exactly little mode distribution network voltage higher, gives by expiring of small power station's rated output and power factor is that the reactive power that sent in 0.90 ~ 0.95 o'clock is all sponged by reactor.0.90 the time Q/P=0.4359, and 0.95 o'clock Q/P=0.3123 considers that small power station's distribution transforming of boosting also can sponge a part of reactive power, for this reason, the compensation total capacity of reactor can be taken as 30% ~ 40% of generator capacity and require configuration.Because the capacity that distribution becomes is apparent power and generator capacity is active power, both have certain difference, and the former is often than the large 20%-30% of the latter, so generator capacity also is equivalent to about 20% ~ 35% of the distribution varying capacity that boosts.And the ratio of this configuration is suitable at the configuration capacity of distribution low pressure side with the capacitive reactive power compensation, is accepted than the user who is easier to as comprising the owner of small power station.
The needs of pressure regulation when adapting to voltage fluctuation, the low pressure shunt reactor should suitably carry out switching.
Determining of the electric pressure of inductive reactive power compensation
Installation site (electric pressure) difference of shunt reactor in the small hydropower station, the effect of bringing be difference to some extent also.Suppose that the step-up transformer no-load voltage ratio in the small hydropower station is 0.38/11.When small power station sends on a small quantity when idle, this moment, the direction of P and Q was consistent.By the π type equivalent circuit of transformer as can be known, if when shunt reactor was installed the 10kV side, the power that small power station sends flow through equiva lent impedance 1/kZ
TCan produce a pressure drop Δ V
1And when shunt reactor is installed in the 380V side of the change of boosting, flow through 1/kZ
TPower then can reduce the pressure drop Δ V that causes
2Inevitable less than Δ V
1, so distribution line terminal voltage value is low when being bound to be contained in the high-pressure side than reactor.When small power station's leading phase operation, P and Q opposite direction when reactor is installed in the 380V side, flow through 1/kZ
TReactive power many must be installed in the 10kV side than reactor the time, by dV=(PR-QX)/V as can be known, Q is larger, then dV is less, corresponding distribution line terminal voltage is also just lower.As seen, see technically that inductive reactive power compensation adopts low pressure grade better effects if, and equipment investment is lower.
Beneficial effect: the present invention reaches the situation of predetermined strength corresponding to criterion for small power station's voltage out-of-limit, by the low pressure side configuration shunt reactor that boosts at small hydropower station, control ability to line voltage distribution significantly strengthens, and has good practical value and operability.
Description of drawings
Fig. 1 boosts in the small hydropower station to become π type Equivalent Model;
Fig. 2 is the distribution line simulation model;
Fig. 3 is the white stone line winding diagram of station, stone 35kV Huangpu, application example Shaoguan power grid level ground 10kV F20;
Fig. 4 is each node voltage amplitude before the shunt reactor configuration;
Fig. 5 is each node voltage amplitude after the shunt reactor configuration.
Embodiment
Below in conjunction with simulation model and application example this patent is described further.
Simulation model
Consult Fig. 1 ~ 2, Figure 1 shows that the π type equivalent circuit of step-up transformer in the small hydropower station, Figure 2 shows that the simulation model of inductive reactive power compensation method of the present invention.Concrete implementation step is as follows:
1, little mode small power station oestruses greatly and carries out initial trend simulation calculation under the condition, and it is as shown in table 1 to obtain each point voltage of circuit:
Initial each node voltage of table 1
As seen from the above table, when distribution line did not carry out reactive power compensation under the rich little mode, the whole piece line voltage distribution was generally higher, and terminal voltage even up to 11.321kV has exceeded the upper voltage limit of regulation.
2, the inductive reactive power compensation method that proposes according to this patent is chosen in respectively the shunt reactor that the 380V of small power station side and 10kV side are installed one group of 200kvar, re-start trend and calculate, and the each point voltage condition compares as shown in table 2 in the table 1;
Node voltage contrast before and after table 2 compensation
As can be seen from Table 2, small power station boost shunt reactor become to be installed after, each node voltage be improved significantly.Comparatively speaking, when when the change 10kV side of boosting is installed shunt reactor, the distribution line terminal voltage is 10.73kV, still is higher than upper voltage limit; And when the 380V side compensated, the whole piece line voltage distribution all was positioned at the normal voltage scope, and line end voltage is 10.587kV.Therefore, install additional in the low pressure side of boosting and to compare the 10kV side to install the reactor hypotensive effect additional remarkable, and investment still less, overall economic efficiency is high.
Application example
Figure 3 shows that the white stone line physical cabling of stone 35kV Huangpu, Shaoguan power grid level ground station 10kV F20 figure, this circuit comprises 7 hydroelectric stations totally 12 step-up transformers, and small power station's total installation of generating capacity is 3830kVA.
Each node voltage of circuit as shown in Figure 4 under the little mode of wet season.As can be seen from Figure, each point voltage of circuit all is not in higher level when compensating, and according to statistics, whole piece circuit voltage out-of-limit rate is up to 63.63%, and ceiling voltage is 11.00kV.
At small power station's step-up transformer low voltage side configuration inductive reactive power compensation, method may further comprise the steps according to this patent method:
The selection of S1 inductive reactive power compensation reactor capacity: get 30% ~ 40% of small power station's generator rated capacity; This routine value sees Table 3.
The selection of S2 shunt reactor compensated position: install in the access of small hydropower station step-up transformer low voltage side;
It is fixed that the grouping situation of S3 low pressure shunt reactor is come according to the reactor amount of capacity, 150kvar and following not dividing into groups, and 150 ~ 300kvar divides two groups, and what 300kvar was above divides three groups; Low and power station, Huifeng is low except rich 5 stations is divided into that all the other do not divide into groups two groups for this example.
Determining of S4 shunt reactor electric pressure: adopt the low pressure grade consistent with step-up transformer low voltage side grade in the small hydropower station.This example adopts the 380V electric pressure.
The compensation configuring condition is as shown in table 3.
Table 3 compensation configuring condition
Circuit each node voltage effect such as Fig. 5 after the compensation all are positioned at zone of reasonableness.
Can be found out by above-mentioned application example, adopt reactive power compensation collocation method proposed by the invention to choose configuration capacity and compensation place, can effectively improve the regulating and controlling voltage ability of power distribution network under rich little mode, improve quality of voltage, and have concurrently antitheft and be easy to the characteristics such as management.Under actual conditions, for so that the shunt reactor voltage regulation result can adapt to the needs of voltage fluctuation, should consider to divide into groups to carry out inductive reactive power compensation according to fluctuating range, shunt reactor must increase automatic control switch for this reason.
Claims (2)
1. an inductive reactive power compensation in parallel suppresses to contain the method for small power station's power distribution network steady-state overvoltage, may further comprise the steps:
The selection of S1 inductive reactive power compensation reactor capacity: get 30% ~ 40% of small power station's generator rated capacity;
The selection of S2 shunt reactor compensated position: install in the access of small hydropower station step-up transformer low voltage side;
It is fixed that the grouping situation of S3 low pressure shunt reactor is come according to the reactor amount of capacity, 150kvar and following not dividing into groups, and 150 ~ 300kvar divides two groups, and what 300kvar was above divides three groups;
Determining of S4 shunt reactor electric pressure: adopt the low pressure grade consistent with step-up transformer low voltage side grade in the small hydropower station.
2. inductive reactive power compensation in parallel according to claim 1 suppresses to contain the method for small power station's power distribution network steady-state overvoltage, and it is characterized in that: described inductive reactive power compensation in parallel is reactor.
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Cited By (2)
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| CN104009480A (en) * | 2014-05-26 | 2014-08-27 | 广东电网公司电力科学研究院 | Reactive voltage control method and system based on reactive voltage control device |
| CN106208093A (en) * | 2016-09-20 | 2016-12-07 | 广东电网有限责任公司河源供电局 | Power station reactor collocation method and system |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104009480A (en) * | 2014-05-26 | 2014-08-27 | 广东电网公司电力科学研究院 | Reactive voltage control method and system based on reactive voltage control device |
| CN104009480B (en) * | 2014-05-26 | 2016-08-24 | 广东电网公司电力科学研究院 | Voltage powerless control method based on voltage and reactive power control system and system |
| CN106208093A (en) * | 2016-09-20 | 2016-12-07 | 广东电网有限责任公司河源供电局 | Power station reactor collocation method and system |
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Application publication date: 20130313 |